| Age | Commit message (Collapse) | Author |
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The proactive compaction[1] gets triggered for every 500msec and run
compaction on the node for COMPACTION_HPAGE_ORDER (usually order-9) pages
based on the value set to sysctl.compaction_proactiveness. Triggering the
compaction for every 500msec in search of COMPACTION_HPAGE_ORDER pages is
not needed for all applications, especially on the embedded system
usecases which may have few MB's of RAM. Enabling the proactive
compaction in its state will endup in running almost always on such
systems.
Other side, proactive compaction can still be very much useful for getting
a set of higher order pages in some controllable manner(controlled by
using the sysctl.compaction_proactiveness). So, on systems where enabling
the proactive compaction always may proove not required, can trigger the
same from user space on write to its sysctl interface. As an example, say
app launcher decide to launch the memory heavy application which can be
launched fast if it gets more higher order pages thus launcher can prepare
the system in advance by triggering the proactive compaction from
userspace.
This triggering of proactive compaction is done on a write to
sysctl.compaction_proactiveness by user.
[1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=facdaa917c4d5a376d09d25865f5a863f906234a
[akpm@linux-foundation.org: tweak vm.rst, per Mike]
Link: https://lkml.kernel.org/r/1627653207-12317-1-git-send-email-charante@codeaurora.org
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Rafael Aquini <aquini@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Nitin Gupta <nigupta@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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A program may create multiple interval timers using timer_create(). For
each timer the kernel preallocates a "queued real-time signal",
Consequently, the number of timers is limited by the RLIMIT_SIGPENDING
resource limit. The allocated object is quite small, ~250 bytes, but even
the default signal limits allow to consume up to 100 megabytes per user.
It makes sense to account for them to limit the host's memory consumption
from inside the memcg-limited container.
Link: https://lkml.kernel.org/r/57795560-025c-267c-6b1a-dea852d95530@virtuozzo.com
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Yutian Yang <nglaive@gmail.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When a user send a signal to any another processes it forces the kernel to
allocate memory for 'struct sigqueue' objects. The number of signals is
limited by RLIMIT_SIGPENDING resource limit, but even the default settings
allow each user to consume up to several megabytes of memory.
It makes sense to account for these allocations to restrict the host's
memory consumption from inside the memcg-limited container.
Link: https://lkml.kernel.org/r/e34e958c-e785-712e-a62a-2c7b66c646c7@virtuozzo.com
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Yutian Yang <nglaive@gmail.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Container admin can create new namespaces and force kernel to allocate up
to several pages of memory for the namespaces and its associated
structures.
Net and uts namespaces have enabled accounting for such allocations. It
makes sense to account for rest ones to restrict the host's memory
consumption from inside the memcg-limited container.
Link: https://lkml.kernel.org/r/5525bcbf-533e-da27-79b7-158686c64e13@virtuozzo.com
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Yutian Yang <nglaive@gmail.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Commit 5d097056c9a0 ("kmemcg: account certain kmem allocations to memcg")
enabled memcg accounting for pids allocated from init_pid_ns.pid_cachep,
but forgot to adjust the setting for nested pid namespaces. As a result,
pid memory is not accounted exactly where it is really needed, inside
memcg-limited containers with their own pid namespaces.
Pid was one the first kernel objects enabled for memcg accounting.
init_pid_ns.pid_cachep marked by SLAB_ACCOUNT and we can expect that any
new pids in the system are memcg-accounted.
Though recently I've noticed that it is wrong. nested pid namespaces
creates own slab caches for pid objects, nested pids have increased size
because contain id both for all parent and for own pid namespaces. The
problem is that these slab caches are _NOT_ marked by SLAB_ACCOUNT, as a
result any pids allocated in nested pid namespaces are not
memcg-accounted.
Pid struct in nested pid namespace consumes up to 500 bytes memory, 100000
such objects gives us up to ~50Mb unaccounted memory, this allow container
to exceed assigned memcg limits.
Link: https://lkml.kernel.org/r/8b6de616-fd1a-02c6-cbdb-976ecdcfa604@virtuozzo.com
Fixes: 5d097056c9a0 ("kmemcg: account certain kmem allocations to memcg")
Cc: stable@vger.kernel.org
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Borislav Petkov:
- Have get_push_task() check whether current has migration disabled and
thus avoid useless invocations of the migration thread
- Rework initialization flow so that all rq->core's are initialized,
even of CPUs which have not been onlined yet, so that iterating over
them all works as expected
* tag 'sched_urgent_for_v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched: Fix get_push_task() vs migrate_disable()
sched: Fix Core-wide rq->lock for uninitialized CPUs
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git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
"Networking fixes, including fixes from can and bpf.
Closing three hw-dependent regressions. Any fixes of note are in the
'old code' category. Nothing blocking release from our perspective.
Current release - regressions:
- stmmac: revert "stmmac: align RX buffers"
- usb: asix: ax88772: move embedded PHY detection as early as
possible
- usb: asix: do not call phy_disconnect() for ax88178
- Revert "net: really fix the build...", from Kalle to fix QCA6390
Current release - new code bugs:
- phy: mediatek: add the missing suspend/resume callbacks
Previous releases - regressions:
- qrtr: fix another OOB Read in qrtr_endpoint_post
- stmmac: dwmac-rk: fix unbalanced pm_runtime_enable warnings
Previous releases - always broken:
- inet: use siphash in exception handling
- ip_gre: add validation for csum_start
- bpf: fix ringbuf helper function compatibility
- rtnetlink: return correct error on changing device netns
- e1000e: do not try to recover the NVM checksum on Tiger Lake"
* tag 'net-5.14-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (43 commits)
Revert "net: really fix the build..."
net: hns3: fix get wrong pfc_en when query PFC configuration
net: hns3: fix GRO configuration error after reset
net: hns3: change the method of getting cmd index in debugfs
net: hns3: fix duplicate node in VLAN list
net: hns3: fix speed unknown issue in bond 4
net: hns3: add waiting time before cmdq memory is released
net: hns3: clear hardware resource when loading driver
net: fix NULL pointer reference in cipso_v4_doi_free
rtnetlink: Return correct error on changing device netns
net: dsa: hellcreek: Adjust schedule look ahead window
net: dsa: hellcreek: Fix incorrect setting of GCL
cxgb4: dont touch blocked freelist bitmap after free
ipv4: use siphash instead of Jenkins in fnhe_hashfun()
ipv6: use siphash in rt6_exception_hash()
can: usb: esd_usb2: esd_usb2_rx_event(): fix the interchange of the CAN RX and TX error counters
net: usb: asix: ax88772: fix boolconv.cocci warnings
net/sched: ets: fix crash when flipping from 'strict' to 'quantum'
qede: Fix memset corruption
net: stmmac: fix kernel panic due to NULL pointer dereference of buf->xdp
...
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push_rt_task() attempts to move the currently running task away if the
next runnable task has migration disabled and therefore is pinned on the
current CPU.
The current task is retrieved via get_push_task() which only checks for
nr_cpus_allowed == 1, but does not check whether the task has migration
disabled and therefore cannot be moved either. The consequence is a
pointless invocation of the migration thread which correctly observes
that the task cannot be moved.
Return NULL if the task has migration disabled and cannot be moved to
another CPU.
Fixes: a7c81556ec4d3 ("sched: Fix migrate_disable() vs rt/dl balancing")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210826133738.yiotqbtdaxzjsnfj@linutronix.de
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git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull ucount fixes from Eric Biederman:
"This branch fixes a regression that made it impossible to increase
rlimits that had been converted to the ucount infrastructure, and also
fixes a reference counting bug where the reference was not incremented
soon enough.
The fixes are trivial and the bugs have been encountered in the wild,
and the fixes have been tested"
* 'for-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
ucounts: Increase ucounts reference counter before the security hook
ucounts: Fix regression preventing increasing of rlimits in init_user_ns
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We need to increment the ucounts reference counter befor security_prepare_creds()
because this function may fail and abort_creds() will try to decrement
this reference.
[ 96.465056][ T8641] FAULT_INJECTION: forcing a failure.
[ 96.465056][ T8641] name fail_page_alloc, interval 1, probability 0, space 0, times 0
[ 96.478453][ T8641] CPU: 1 PID: 8641 Comm: syz-executor668 Not tainted 5.14.0-rc6-syzkaller #0
[ 96.487215][ T8641] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 96.497254][ T8641] Call Trace:
[ 96.500517][ T8641] dump_stack_lvl+0x1d3/0x29f
[ 96.505758][ T8641] ? show_regs_print_info+0x12/0x12
[ 96.510944][ T8641] ? log_buf_vmcoreinfo_setup+0x498/0x498
[ 96.516652][ T8641] should_fail+0x384/0x4b0
[ 96.521141][ T8641] prepare_alloc_pages+0x1d1/0x5a0
[ 96.526236][ T8641] __alloc_pages+0x14d/0x5f0
[ 96.530808][ T8641] ? __rmqueue_pcplist+0x2030/0x2030
[ 96.536073][ T8641] ? lockdep_hardirqs_on_prepare+0x3e2/0x750
[ 96.542056][ T8641] ? alloc_pages+0x3f3/0x500
[ 96.546635][ T8641] allocate_slab+0xf1/0x540
[ 96.551120][ T8641] ___slab_alloc+0x1cf/0x350
[ 96.555689][ T8641] ? kzalloc+0x1d/0x30
[ 96.559740][ T8641] __kmalloc+0x2e7/0x390
[ 96.563980][ T8641] ? kzalloc+0x1d/0x30
[ 96.568029][ T8641] kzalloc+0x1d/0x30
[ 96.571903][ T8641] security_prepare_creds+0x46/0x220
[ 96.577174][ T8641] prepare_creds+0x411/0x640
[ 96.581747][ T8641] __sys_setfsuid+0xe2/0x3a0
[ 96.586333][ T8641] do_syscall_64+0x3d/0xb0
[ 96.590739][ T8641] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 96.596611][ T8641] RIP: 0033:0x445a69
[ 96.600483][ T8641] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
[ 96.620152][ T8641] RSP: 002b:00007f1054173318 EFLAGS: 00000246 ORIG_RAX: 000000000000007a
[ 96.628543][ T8641] RAX: ffffffffffffffda RBX: 00000000004ca4c8 RCX: 0000000000445a69
[ 96.636600][ T8641] RDX: 0000000000000010 RSI: 00007f10541732f0 RDI: 0000000000000000
[ 96.644550][ T8641] RBP: 00000000004ca4c0 R08: 0000000000000001 R09: 0000000000000000
[ 96.652500][ T8641] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca4cc
[ 96.660631][ T8641] R13: 00007fffffe0b62f R14: 00007f1054173400 R15: 0000000000022000
Fixes: 905ae01c4ae2 ("Add a reference to ucounts for each cred")
Reported-by: syzbot+01985d7909f9468f013c@syzkaller.appspotmail.com
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://lkml.kernel.org/r/97433b1742c3331f02ad92de5a4f07d673c90613.1629735352.git.legion@kernel.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
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"Ma, XinjianX" <xinjianx.ma@intel.com> reported:
> When lkp team run kernel selftests, we found after these series of patches, testcase mqueue: mq_perf_tests
> in kselftest failed with following message.
>
> # selftests: mqueue: mq_perf_tests
> #
> # Initial system state:
> # Using queue path: /mq_perf_tests
> # RLIMIT_MSGQUEUE(soft): 819200
> # RLIMIT_MSGQUEUE(hard): 819200
> # Maximum Message Size: 8192
> # Maximum Queue Size: 10
> # Nice value: 0
> #
> # Adjusted system state for testing:
> # RLIMIT_MSGQUEUE(soft): (unlimited)
> # RLIMIT_MSGQUEUE(hard): (unlimited)
> # Maximum Message Size: 16777216
> # Maximum Queue Size: 65530
> # Nice value: -20
> # Continuous mode: (disabled)
> # CPUs to pin: 3
> # ./mq_perf_tests: mq_open() at 296: Too many open files
> not ok 2 selftests: mqueue: mq_perf_tests # exit=1
> ```
>
> Test env:
> rootfs: debian-10
> gcc version: 9
After investigation the problem turned out to be that ucount_max for
the rlimits in init_user_ns was being set to the initial rlimit value.
The practical problem is that ucount_max provides a limit that
applications inside the user namespace can not exceed. Which means in
practice that rlimits that have been converted to use the ucount
infrastructure were not able to exceend their initial rlimits.
Solve this by setting the relevant values of ucount_max to
RLIM_INIFINITY. A limit in init_user_ns is pointless so the code
should allow the values to grow as large as possible without riscking
an underflow or an overflow.
As the ltp test case was a bit of a pain I have reproduced the rlimit failure
and tested the fix with the following little C program:
> #include <stdio.h>
> #include <fcntl.h>
> #include <sys/stat.h>
> #include <mqueue.h>
> #include <sys/time.h>
> #include <sys/resource.h>
> #include <errno.h>
> #include <string.h>
> #include <stdlib.h>
> #include <limits.h>
> #include <unistd.h>
>
> int main(int argc, char **argv)
> {
> struct mq_attr mq_attr;
> struct rlimit rlim;
> mqd_t mqd;
> int ret;
>
> ret = getrlimit(RLIMIT_MSGQUEUE, &rlim);
> if (ret != 0) {
> fprintf(stderr, "getrlimit(RLIMIT_MSGQUEUE) failed: %s\n", strerror(errno));
> exit(EXIT_FAILURE);
> }
> printf("RLIMIT_MSGQUEUE %lu %lu\n",
> rlim.rlim_cur, rlim.rlim_max);
> rlim.rlim_cur = RLIM_INFINITY;
> rlim.rlim_max = RLIM_INFINITY;
> ret = setrlimit(RLIMIT_MSGQUEUE, &rlim);
> if (ret != 0) {
> fprintf(stderr, "setrlimit(RLIMIT_MSGQUEUE, RLIM_INFINITY) failed: %s\n", strerror(errno));
> exit(EXIT_FAILURE);
> }
>
> memset(&mq_attr, 0, sizeof(struct mq_attr));
> mq_attr.mq_maxmsg = 65536 - 1;
> mq_attr.mq_msgsize = 16*1024*1024 - 1;
>
> mqd = mq_open("/mq_rlimit_test", O_RDONLY|O_CREAT, 0600, &mq_attr);
> if (mqd == (mqd_t)-1) {
> fprintf(stderr, "mq_open failed: %s\n", strerror(errno));
> exit(EXIT_FAILURE);
> }
> ret = mq_close(mqd);
> if (ret) {
> fprintf(stderr, "mq_close failed; %s\n", strerror(errno));
> exit(EXIT_FAILURE);
> }
>
> return EXIT_SUCCESS;
> }
Fixes: 6e52a9f0532f ("Reimplement RLIMIT_MSGQUEUE on top of ucounts")
Fixes: d7c9e99aee48 ("Reimplement RLIMIT_MEMLOCK on top of ucounts")
Fixes: d64696905554 ("Reimplement RLIMIT_SIGPENDING on top of ucounts")
Fixes: 21d1c5e386bc ("Reimplement RLIMIT_NPROC on top of ucounts")
Reported-by: kernel test robot lkp@intel.com
Acked-by: Alexey Gladkov <legion@kernel.org>
Link: https://lkml.kernel.org/r/87eeajswfc.fsf_-_@disp2133
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Commit 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support
for it") extended check_map_func_compatibility() by enforcing map -> helper
function match, but not helper -> map type match.
Due to this all of the bpf_ringbuf_*() helper functions could be used with
a wrong map type such as array or hash map, leading to invalid access due
to type confusion.
Also, both BPF_FUNC_ringbuf_{submit,discard} have ARG_PTR_TO_ALLOC_MEM as
argument and not a BPF map. Therefore, their check_map_func_compatibility()
presence is incorrect since it's only for map type checking.
Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it")
Reported-by: Ryota Shiga (Flatt Security)
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
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Eugene tripped over the case where rq_lock(), as called in a
for_each_possible_cpu() loop came apart because rq->core hadn't been
setup yet.
This is a somewhat unusual, but valid case.
Rework things such that rq->core is initialized to point at itself. IOW
initialize each CPU as a single threaded Core. CPU online will then join
the new CPU (thread) to an existing Core where needed.
For completeness sake, have CPU offline fully undo the state so as to
not presume the topology will match the next time it comes online.
Fixes: 9edeaea1bc45 ("sched: Core-wide rq->lock")
Reported-by: Eugene Syromiatnikov <esyr@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Don <joshdon@google.com>
Tested-by: Eugene Syromiatnikov <esyr@redhat.com>
Link: https://lkml.kernel.org/r/YR473ZGeKqMs6kw+@hirez.programming.kicks-ass.net
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git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
"Networking fixes, including fixes from bpf, wireless and mac80211
trees.
Current release - regressions:
- tipc: call tipc_wait_for_connect only when dlen is not 0
- mac80211: fix locking in ieee80211_restart_work()
Current release - new code bugs:
- bpf: add rcu_read_lock in bpf_get_current_[ancestor_]cgroup_id()
- ethernet: ice: fix perout start time rounding
- wwan: iosm: prevent underflow in ipc_chnl_cfg_get()
Previous releases - regressions:
- bpf: clear zext_dst of dead insns
- sch_cake: fix srchost/dsthost hashing mode
- vrf: reset skb conntrack connection on VRF rcv
- net/rds: dma_map_sg is entitled to merge entries
Previous releases - always broken:
- ethernet: bnxt: fix Tx path locking and races, add Rx path
barriers"
* tag 'net-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (42 commits)
net: dpaa2-switch: disable the control interface on error path
Revert "flow_offload: action should not be NULL when it is referenced"
iavf: Fix ping is lost after untrusted VF had tried to change MAC
i40e: Fix ATR queue selection
r8152: fix the maximum number of PLA bp for RTL8153C
r8152: fix writing USB_BP2_EN
mptcp: full fully established support after ADD_ADDR
mptcp: fix memory leak on address flush
net/rds: dma_map_sg is entitled to merge entries
net: mscc: ocelot: allow forwarding from bridge ports to the tag_8021q CPU port
net: asix: fix uninit value bugs
ovs: clear skb->tstamp in forwarding path
net: mdio-mux: Handle -EPROBE_DEFER correctly
net: mdio-mux: Don't ignore memory allocation errors
net: mdio-mux: Delete unnecessary devm_kfree
net: dsa: sja1105: fix use-after-free after calling of_find_compatible_node, or worse
sch_cake: fix srchost/dsthost hashing mode
ixgbe, xsk: clean up the resources in ixgbe_xsk_pool_enable error path
net: qlcnic: add missed unlock in qlcnic_83xx_flash_read32
mac80211: fix locking in ieee80211_restart_work()
...
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Daniel Borkmann says:
====================
pull-request: bpf 2021-08-19
We've added 3 non-merge commits during the last 3 day(s) which contain
a total of 3 files changed, 29 insertions(+), 6 deletions(-).
The main changes are:
1) Fix to clear zext_dst for dead instructions which was causing invalid program
rejections on JITs with bpf_jit_needs_zext such as s390x, from Ilya Leoshkevich.
2) Fix RCU splat in bpf_get_current_{ancestor_,}cgroup_id() helpers when they are
invoked from sleepable programs, from Yonghong Song.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests, bpf: Test that dead ldx_w insns are accepted
bpf: Clear zext_dst of dead insns
bpf: Add rcu_read_lock in bpf_get_current_[ancestor_]cgroup_id() helpers
====================
Link: https://lore.kernel.org/r/20210819144904.20069-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull clang cfi fix from Kees Cook:
- Use rcu_read_{un}lock_sched_notrace to avoid recursion (Elliot Berman)
* tag 'cfi-v5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
cfi: Use rcu_read_{un}lock_sched_notrace
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt:
"Limit the shooting in the foot of tp_printk
The "tp_printk" option redirects the trace event output to printk at
boot up. This is useful when a machine crashes before boot where the
trace events can not be retrieved by the in kernel ring buffer. But it
can be "dangerous" because trace events can be located in high
frequency locations such as interrupts and the scheduler, where a
printk can slow it down that it live locks the machine (because by the
time the printk finishes, the next event is triggered). Thus tp_printk
must be used with care.
It was discovered that the filter logic to trace events does not apply
to the tp_printk events. This can cause a surprise and live lock when
the user expects it to be filtered to limit the amount of events
printed to the console when in fact it still prints everything"
* tag 'trace-v5.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Apply trace filters on all output channels
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"Fixes and clean ups to tracing:
- Fix header alignment when PREEMPT_RT is enabled for osnoise tracer
- Inject "stop" event to see where osnoise stopped the trace
- Define DYNAMIC_FTRACE_WITH_ARGS as some code had an #ifdef for it
- Fix erroneous message for bootconfig cmdline parameter
- Fix crash caused by not found variable in histograms"
* tag 'trace-v5.14-rc5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing / histogram: Fix NULL pointer dereference on strcmp() on NULL event name
init: Suppress wrong warning for bootconfig cmdline parameter
tracing: define needed config DYNAMIC_FTRACE_WITH_ARGS
trace/osnoise: Print a stop tracing message
trace/timerlat: Add a header with PREEMPT_RT additional fields
trace/osnoise: Add a header with PREEMPT_RT additional fields
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The event filters are not applied on all of the output, which results in
the flood of printk when using tp_printk. Unfolding
event_trigger_unlock_commit_regs() into trace_event_buffer_commit(), so
the filters can be applied on every output.
Link: https://lkml.kernel.org/r/20210814034538.8428-1-kernelfans@gmail.com
Cc: stable@vger.kernel.org
Fixes: 0daa2302968c1 ("tracing: Add tp_printk cmdline to have tracepoints go to printk()")
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Thomas Gleixner:
"A set of fixes for PCI/MSI and x86 interrupt startup:
- Mask all MSI-X entries when enabling MSI-X otherwise stale unmasked
entries stay around e.g. when a crashkernel is booted.
- Enforce masking of a MSI-X table entry when updating it, which
mandatory according to speification
- Ensure that writes to MSI[-X} tables are flushed.
- Prevent invalid bits being set in the MSI mask register
- Properly serialize modifications to the mask cache and the mask
register for multi-MSI.
- Cure the violation of the affinity setting rules on X86 during
interrupt startup which can cause lost and stale interrupts. Move
the initial affinity setting ahead of actualy enabling the
interrupt.
- Ensure that MSI interrupts are completely torn down before freeing
them in the error handling case.
- Prevent an array out of bounds access in the irq timings code"
* tag 'irq-urgent-2021-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
driver core: Add missing kernel doc for device::msi_lock
genirq/msi: Ensure deactivation on teardown
genirq/timings: Prevent potential array overflow in __irq_timings_store()
x86/msi: Force affinity setup before startup
x86/ioapic: Force affinity setup before startup
genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP
PCI/MSI: Protect msi_desc::masked for multi-MSI
PCI/MSI: Use msi_mask_irq() in pci_msi_shutdown()
PCI/MSI: Correct misleading comments
PCI/MSI: Do not set invalid bits in MSI mask
PCI/MSI: Enforce MSI[X] entry updates to be visible
PCI/MSI: Enforce that MSI-X table entry is masked for update
PCI/MSI: Mask all unused MSI-X entries
PCI/MSI: Enable and mask MSI-X early
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Borislav Petkov:
- Fix a CONFIG symbol's spelling
* tag 'locking_urgent_for_v5.14_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rtmutex: Use the correct rtmutex debugging config option
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"access skb fields ok" verifier test fails on s390 with the "verifier
bug. zext_dst is set, but no reg is defined" message. The first insns
of the test prog are ...
0: 61 01 00 00 00 00 00 00 ldxw %r0,[%r1+0]
8: 35 00 00 01 00 00 00 00 jge %r0,0,1
10: 61 01 00 08 00 00 00 00 ldxw %r0,[%r1+8]
... and the 3rd one is dead (this does not look intentional to me, but
this is a separate topic).
sanitize_dead_code() converts dead insns into "ja -1", but keeps
zext_dst. When opt_subreg_zext_lo32_rnd_hi32() tries to parse such
an insn, it sees this discrepancy and bails. This problem can be seen
only with JITs whose bpf_jit_needs_zext() returns true.
Fix by clearning dead insns' zext_dst.
The commits that contributed to this problem are:
1. 5aa5bd14c5f8 ("bpf: add initial suite for selftests"), which
introduced the test with the dead code.
2. 5327ed3d44b7 ("bpf: verifier: mark verified-insn with
sub-register zext flag"), which introduced the zext_dst flag.
3. 83a2881903f3 ("bpf: Account for BPF_FETCH in
insn_has_def32()"), which introduced the sanity check.
4. 9183671af6db ("bpf: Fix leakage under speculation on
mispredicted branches"), which bisect points to.
It's best to fix this on stable branches that contain the second one,
since that's the point where the inconsistency was introduced.
Fixes: 5327ed3d44b7 ("bpf: verifier: mark verified-insn with sub-register zext flag")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210812151811.184086-2-iii@linux.ibm.com
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git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
"Networking fixes, including fixes from netfilter, bpf, can and
ieee802154.
The size of this is pretty normal, but we got more fixes for 5.14
changes this week than last week. Nothing major but the trend is the
opposite of what we like. We'll see how the next week goes..
Current release - regressions:
- r8169: fix ASPM-related link-up regressions
- bridge: fix flags interpretation for extern learn fdb entries
- phy: micrel: fix link detection on ksz87xx switch
- Revert "tipc: Return the correct errno code"
- ptp: fix possible memory leak caused by invalid cast
Current release - new code bugs:
- bpf: add missing bpf_read_[un]lock_trace() for syscall program
- bpf: fix potentially incorrect results with bpf_get_local_storage()
- page_pool: mask the page->signature before the checking, avoid dma
mapping leaks
- netfilter: nfnetlink_hook: 5 fixes to information in netlink dumps
- bnxt_en: fix firmware interface issues with PTP
- mlx5: Bridge, fix ageing time
Previous releases - regressions:
- linkwatch: fix failure to restore device state across
suspend/resume
- bareudp: fix invalid read beyond skb's linear data
Previous releases - always broken:
- bpf: fix integer overflow involving bucket_size
- ppp: fix issues when desired interface name is specified via
netlink
- wwan: mhi_wwan_ctrl: fix possible deadlock
- dsa: microchip: ksz8795: fix number of VLAN related bugs
- dsa: drivers: fix broken backpressure in .port_fdb_dump
- dsa: qca: ar9331: make proper initial port defaults
Misc:
- bpf: add lockdown check for probe_write_user helper
- netfilter: conntrack: remove offload_pickup sysctl before 5.14 is
out
- netfilter: conntrack: collect all entries in one cycle,
heuristically slow down garbage collection scans on idle systems to
prevent frequent wake ups"
* tag 'net-5.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (87 commits)
vsock/virtio: avoid potential deadlock when vsock device remove
wwan: core: Avoid returning NULL from wwan_create_dev()
net: dsa: sja1105: unregister the MDIO buses during teardown
Revert "tipc: Return the correct errno code"
net: mscc: Fix non-GPL export of regmap APIs
net: igmp: increase size of mr_ifc_count
MAINTAINERS: switch to my OMP email for Renesas Ethernet drivers
tcp_bbr: fix u32 wrap bug in round logic if bbr_init() called after 2B packets
net: pcs: xpcs: fix error handling on failed to allocate memory
net: linkwatch: fix failure to restore device state across suspend/resume
net: bridge: fix memleak in br_add_if()
net: switchdev: zero-initialize struct switchdev_notifier_fdb_info emitted by drivers towards the bridge
net: bridge: fix flags interpretation for extern learn fdb entries
net: dsa: sja1105: fix broken backpressure in .port_fdb_dump
net: dsa: lantiq: fix broken backpressure in .port_fdb_dump
net: dsa: lan9303: fix broken backpressure in .port_fdb_dump
net: dsa: hellcreek: fix broken backpressure in .port_fdb_dump
bpf, core: Fix kernel-doc notation
net: igmp: fix data-race in igmp_ifc_timer_expire()
net: Fix memory leak in ieee802154_raw_deliver
...
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The following commands:
# echo 'read_max u64 size;' > synthetic_events
# echo 'hist:keys=common_pid:count=count:onmax($count).trace(read_max,count)' > events/syscalls/sys_enter_read/trigger
Causes:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP
CPU: 4 PID: 1763 Comm: bash Not tainted 5.14.0-rc2-test+ #155
Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01
v03.03 07/14/2016
RIP: 0010:strcmp+0xc/0x20
Code: 75 f7 31 c0 0f b6 0c 06 88 0c 02 48 83 c0 01 84 c9 75 f1 4c 89 c0
c3 0f 1f 80 00 00 00 00 31 c0 eb 08 48 83 c0 01 84 d2 74 0f <0f> b6 14 07
3a 14 06 74 ef 19 c0 83 c8 01 c3 31 c0 c3 66 90 48 89
RSP: 0018:ffffb5fdc0963ca8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffffb3a4e040 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff9714c0d0b640 RDI: 0000000000000000
RBP: 0000000000000000 R08: 00000022986b7cde R09: ffffffffb3a4dff8
R10: 0000000000000000 R11: 0000000000000000 R12: ffff9714c50603c8
R13: 0000000000000000 R14: ffff97143fdf9e48 R15: ffff9714c01a2210
FS: 00007f1fa6785740(0000) GS:ffff9714da400000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000002d863004 CR4: 00000000001706e0
Call Trace:
__find_event_file+0x4e/0x80
action_create+0x6b7/0xeb0
? kstrdup+0x44/0x60
event_hist_trigger_func+0x1a07/0x2130
trigger_process_regex+0xbd/0x110
event_trigger_write+0x71/0xd0
vfs_write+0xe9/0x310
ksys_write+0x68/0xe0
do_syscall_64+0x3b/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f1fa6879e87
The problem was the "trace(read_max,count)" where the "count" should be
"$count" as "onmax()" only handles variables (although it really should be
able to figure out that "count" is a field of sys_enter_read). But there's
a path that does not find the variable and ends up passing a NULL for the
event, which ends up getting passed to "strcmp()".
Add a check for NULL to return and error on the command with:
# cat error_log
hist:syscalls:sys_enter_read: error: Couldn't create or find variable
Command: hist:keys=common_pid:count=count:onmax($count).trace(read_max,count)
^
Link: https://lkml.kernel.org/r/20210808003011.4037f8d0@oasis.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 50450603ec9cb tracing: Add 'onmax' hist trigger action support
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Commit 2860cd8a2353 ("livepatch: Use the default ftrace_ops instead of
REGS when ARGS is available") intends to enable config LIVEPATCH when
ftrace with ARGS is available. However, the chain of configs to enable
LIVEPATCH is incomplete, as HAVE_DYNAMIC_FTRACE_WITH_ARGS is available,
but the definition of DYNAMIC_FTRACE_WITH_ARGS, combining DYNAMIC_FTRACE
and HAVE_DYNAMIC_FTRACE_WITH_ARGS, needed to enable LIVEPATCH, is missing
in the commit.
Fortunately, ./scripts/checkkconfigsymbols.py detects this and warns:
DYNAMIC_FTRACE_WITH_ARGS
Referencing files: kernel/livepatch/Kconfig
So, define the config DYNAMIC_FTRACE_WITH_ARGS analogously to the already
existing similar configs, DYNAMIC_FTRACE_WITH_REGS and
DYNAMIC_FTRACE_WITH_DIRECT_CALLS, in ./kernel/trace/Kconfig to connect the
chain of configs.
Link: https://lore.kernel.org/kernel-janitors/CAKXUXMwT2zS9fgyQHKUUiqo8ynZBdx2UEUu1WnV_q0OCmknqhw@mail.gmail.com/
Link: https://lkml.kernel.org/r/20210806195027.16808-1-lukas.bulwahn@gmail.com
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: stable@vger.kernel.org
Fixes: 2860cd8a2353 ("livepatch: Use the default ftrace_ops instead of REGS when ARGS is available")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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When using osnoise/timerlat with stop tracing, sometimes it is
not clear in which CPU the stop condition was hit, mainly
when using some extra events.
Print a message informing in which CPU the trace stopped, like
in the example below:
<idle>-0 [006] d.h. 2932.676616: #1672599 context irq timer_latency 34689 ns
<idle>-0 [006] dNh. 2932.676618: irq_noise: local_timer:236 start 2932.676615639 duration 2391 ns
<idle>-0 [006] dNh. 2932.676620: irq_noise: virtio0-output.0:47 start 2932.676620180 duration 86 ns
<idle>-0 [003] d.h. 2932.676621: #1673374 context irq timer_latency 1200 ns
<idle>-0 [006] d... 2932.676623: thread_noise: swapper/6:0 start 2932.676615964 duration 4339 ns
<idle>-0 [003] dNh. 2932.676623: irq_noise: local_timer:236 start 2932.676620597 duration 1881 ns
<idle>-0 [006] d... 2932.676623: sched_switch: prev_comm=swapper/6 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=timerlat/6 next_pid=852 next_prio=4
timerlat/6-852 [006] .... 2932.676623: #1672599 context thread timer_latency 41931 ns
<idle>-0 [003] d... 2932.676623: thread_noise: swapper/3:0 start 2932.676620854 duration 880 ns
<idle>-0 [003] d... 2932.676624: sched_switch: prev_comm=swapper/3 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=timerlat/3 next_pid=849 next_prio=4
timerlat/6-852 [006] .... 2932.676624: timerlat_main: stop tracing hit on cpu 6
timerlat/3-849 [003] .... 2932.676624: #1673374 context thread timer_latency 4310 ns
Link: https://lkml.kernel.org/r/b30a0d7542adba019185f44ee648e60e14923b11.1626598844.git.bristot@kernel.org
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
|
|
Some extra flags are printed to the trace header when using the
PREEMPT_RT config. The extra flags are: need-resched-lazy,
preempt-lazy-depth, and migrate-disable.
Without printing these fields, the timerlat specific fields are
shifted by three positions, for example:
# tracer: timerlat
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# || /
# |||| ACTIVATION
# TASK-PID CPU# |||| TIMESTAMP ID CONTEXT LATENCY
# | | | |||| | | | |
<idle>-0 [000] d..h... 3279.798871: #1 context irq timer_latency 830 ns
<...>-807 [000] ....... 3279.798881: #1 context thread timer_latency 11301 ns
Add a new header for timerlat with the missing fields, to be used
when the PREEMPT_RT is enabled.
Link: https://lkml.kernel.org/r/babb83529a3211bd0805be0b8c21608230202c55.1626598844.git.bristot@kernel.org
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
|
|
Some extra flags are printed to the trace header when using the
PREEMPT_RT config. The extra flags are: need-resched-lazy,
preempt-lazy-depth, and migrate-disable.
Without printing these fields, the osnoise specific fields are
shifted by three positions, for example:
# tracer: osnoise
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth MAX
# || / SINGLE Interference counters:
# |||| RUNTIME NOISE %% OF CPU NOISE +-----------------------------+
# TASK-PID CPU# |||| TIMESTAMP IN US IN US AVAILABLE IN US HW NMI IRQ SIRQ THREAD
# | | | |||| | | | | | | | | | |
<...>-741 [000] ....... 1105.690909: 1000000 234 99.97660 36 21 0 1001 22 3
<...>-742 [001] ....... 1105.691923: 1000000 281 99.97190 197 7 0 1012 35 14
<...>-743 [002] ....... 1105.691958: 1000000 1324 99.86760 118 11 0 1016 155 143
<...>-744 [003] ....... 1105.691998: 1000000 109 99.98910 21 4 0 1004 33 7
<...>-745 [004] ....... 1105.692015: 1000000 2023 99.79770 97 37 0 1023 52 18
Add a new header for osnoise with the missing fields, to be used
when the PREEMPT_RT is enabled.
Link: https://lkml.kernel.org/r/1f03289d2a51fde5a58c2e7def063dc630820ad1.1626598844.git.bristot@kernel.org
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull ucounts fix from Eric Biederman:
"This fixes the ucount sysctls on big endian architectures.
The counts were expanded to be longs instead of ints, and the sysctl
code was overlooked, so only the low 32bit were being processed. On
litte endian just processing the low 32bits is fine, but on 64bit big
endian processing just the low 32bits results in the high order bits
instead of the low order bits being processed and nothing works
proper.
This change took a little bit to mature as we have the SYSCTL_ZERO,
and SYSCTL_INT_MAX macros that are only usable for sysctls operating
on ints, but unfortunately are not obviously broken. Which resulted in
the versions of this change working on big endian and not on little
endian, because the int SYSCTL_ZERO when extended 64bit wound up being
0x100000000. So we only allowed values greater than 0x100000000 and
less than 0faff. Which unfortunately broken everything that tried to
set the sysctls. (First reported with the windows subsystem for
linux).
I have tested this on x86_64 64bit after first reproducing the
problems with the earlier version of this change, and then verifying
the problems do not exist when we use appropriate long min and max
values for extra1 and extra2"
* 'for-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
ucounts: add missing data type changes
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull seccomp fixes from Kees Cook:
- Fix typo in user notification documentation (Rodrigo Campos)
- Fix userspace counter report when using TSYNC (Hsuan-Chi Kuo, Wiktor
Garbacz)
* tag 'seccomp-v5.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
seccomp: Fix setting loaded filter count during TSYNC
Documentation: seccomp: Fix typo in user notification
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If rcu_read_lock_sched tracing is enabled, the tracing subsystem can
perform a jump which needs to be checked by CFI. For example, stm_ftrace
source is enabled as a module and hooks into enabled ftrace events. This
can cause an recursive loop where find_shadow_check_fn ->
rcu_read_lock_sched -> (call to stm_ftrace generates cfi slowpath) ->
find_shadow_check_fn -> rcu_read_lock_sched -> ...
To avoid the recursion, either the ftrace codes needs to be marked with
__no_cfi or CFI should not trace. Use the "_notrace" in CFI to avoid
tracing so that CFI can guard ftrace.
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Cc: stable@vger.kernel.org
Fixes: cf68fffb66d6 ("add support for Clang CFI")
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210811155914.19550-1-quic_eberman@quicinc.com
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The desired behavior is to set the caller's filter count to thread's.
This value is reported via /proc, so this fixes the inaccurate count
exposed to userspace; it is not used for reference counting, etc.
Signed-off-by: Hsuan-Chi Kuo <hsuanchikuo@gmail.com>
Link: https://lore.kernel.org/r/20210304233708.420597-1-hsuanchikuo@gmail.com
Co-developed-by: Wiktor Garbacz <wiktorg@google.com>
Signed-off-by: Wiktor Garbacz <wiktorg@google.com>
Link: https://lore.kernel.org/lkml/20210810125158.329849-1-wiktorg@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Fixes: c818c03b661c ("seccomp: Report number of loaded filters in /proc/$pid/status")
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Currently, if bpf_get_current_cgroup_id() or
bpf_get_current_ancestor_cgroup_id() helper is
called with sleepable programs e.g., sleepable
fentry/fmod_ret/fexit/lsm programs, a rcu warning
may appear. For example, if I added the following
hack to test_progs/test_lsm sleepable fentry program
test_sys_setdomainname:
--- a/tools/testing/selftests/bpf/progs/lsm.c
+++ b/tools/testing/selftests/bpf/progs/lsm.c
@@ -168,6 +168,10 @@ int BPF_PROG(test_sys_setdomainname, struct pt_regs *regs)
int buf = 0;
long ret;
+ __u64 cg_id = bpf_get_current_cgroup_id();
+ if (cg_id == 1000)
+ copy_test++;
+
ret = bpf_copy_from_user(&buf, sizeof(buf), ptr);
if (len == -2 && ret == 0 && buf == 1234)
copy_test++;
I will hit the following rcu warning:
include/linux/cgroup.h:481 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
1 lock held by test_progs/260:
#0: ffffffffa5173360 (rcu_read_lock_trace){....}-{0:0}, at: __bpf_prog_enter_sleepable+0x0/0xa0
stack backtrace:
CPU: 1 PID: 260 Comm: test_progs Tainted: G O 5.14.0-rc2+ #176
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
dump_stack_lvl+0x56/0x7b
bpf_get_current_cgroup_id+0x9c/0xb1
bpf_prog_a29888d1c6706e09_test_sys_setdomainname+0x3e/0x89c
bpf_trampoline_6442469132_0+0x2d/0x1000
__x64_sys_setdomainname+0x5/0x110
do_syscall_64+0x3a/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
I can get similar warning using bpf_get_current_ancestor_cgroup_id() helper.
syzbot reported a similar issue in [1] for syscall program. Helper
bpf_get_current_cgroup_id() or bpf_get_current_ancestor_cgroup_id()
has the following callchain:
task_dfl_cgroup
task_css_set
task_css_set_check
and we have
#define task_css_set_check(task, __c) \
rcu_dereference_check((task)->cgroups, \
lockdep_is_held(&cgroup_mutex) || \
lockdep_is_held(&css_set_lock) || \
((task)->flags & PF_EXITING) || (__c))
Since cgroup_mutex/css_set_lock is not held and the task
is not existing and rcu read_lock is not held, a warning
will be issued. Note that bpf sleepable program is protected by
rcu_read_lock_trace().
The above sleepable bpf programs are already protected
by migrate_disable(). Adding rcu_read_lock() in these
two helpers will silence the above warning.
I marked the patch fixing 95b861a7935b
("bpf: Allow bpf_get_current_ancestor_cgroup_id for tracing")
which added bpf_get_current_ancestor_cgroup_id() to tracing programs
in 5.14. I think backporting 5.14 is probably good enough as sleepable
progrems are not widely used.
This patch should fix [1] as well since syscall program is a sleepable
program protected with migrate_disable().
[1] https://lore.kernel.org/bpf/0000000000006d5cab05c7d9bb87@google.com/
Fixes: 95b861a7935b ("bpf: Allow bpf_get_current_ancestor_cgroup_id for tracing")
Reported-by: syzbot+7ee5c2c09c284495371f@syzkaller.appspotmail.com
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210810230537.2864668-1-yhs@fb.com
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msi_domain_alloc_irqs() invokes irq_domain_activate_irq(), but
msi_domain_free_irqs() does not enforce deactivation before tearing down
the interrupts.
This happens when PCI/MSI interrupts are set up and never used before being
torn down again, e.g. in error handling pathes. The only place which cleans
that up is the error handling path in msi_domain_alloc_irqs().
Move the cleanup from msi_domain_alloc_irqs() into msi_domain_free_irqs()
to cure that.
Fixes: f3b0946d629c ("genirq/msi: Make sure PCI MSIs are activated early")
Signed-off-by: Bixuan Cui <cuibixuan@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210518033117.78104-1-cuibixuan@huawei.com
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When the interrupt interval is greater than 2 ^ PREDICTION_BUFFER_SIZE *
PREDICTION_FACTOR us and less than 1s, the calculated index will be greater
than the length of irqs->ema_time[]. Check the calculated index before
using it to prevent array overflow.
Fixes: 23aa3b9a6b7d ("genirq/timings: Encapsulate storing function")
Signed-off-by: Ben Dai <ben.dai@unisoc.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210425150903.25456-1-ben.dai9703@gmail.com
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Fix kernel-doc warnings in kernel/bpf/core.c (found by scripts/kernel-doc
and W=1 builds). That is, correct a function name in a comment and add
return descriptions for 2 functions.
Fixes these kernel-doc warnings:
kernel/bpf/core.c:1372: warning: expecting prototype for __bpf_prog_run(). Prototype was for ___bpf_prog_run() instead
kernel/bpf/core.c:1372: warning: No description found for return value of '___bpf_prog_run'
kernel/bpf/core.c:1883: warning: No description found for return value of 'bpf_prog_select_runtime'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210809215229.7556-1-rdunlap@infradead.org
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X86 IO/APIC and MSI interrupts (when used without interrupts remapping)
require that the affinity setup on startup is done before the interrupt is
enabled for the first time as the non-remapped operation mode cannot safely
migrate enabled interrupts from arbitrary contexts. Provide a new irq chip
flag which allows affected hardware to request this.
This has to be opt-in because there have been reports in the past that some
interrupt chips cannot handle affinity setting before startup.
Fixes: 18404756765c ("genirq: Expose default irq affinity mask (take 3)")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210729222542.779791738@linutronix.de
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Commit b910eaaaa4b8 ("bpf: Fix NULL pointer dereference in bpf_get_local_storage()
helper") fixed a bug for bpf_get_local_storage() helper so different tasks
won't mess up with each other's percpu local storage.
The percpu data contains 8 slots so it can hold up to 8 contexts (same or
different tasks), for 8 different program runs, at the same time. This in
general is sufficient. But our internal testing showed the following warning
multiple times:
[...]
warning: WARNING: CPU: 13 PID: 41661 at include/linux/bpf-cgroup.h:193
__cgroup_bpf_run_filter_sock_ops+0x13e/0x180
RIP: 0010:__cgroup_bpf_run_filter_sock_ops+0x13e/0x180
<IRQ>
tcp_call_bpf.constprop.99+0x93/0xc0
tcp_conn_request+0x41e/0xa50
? tcp_rcv_state_process+0x203/0xe00
tcp_rcv_state_process+0x203/0xe00
? sk_filter_trim_cap+0xbc/0x210
? tcp_v6_inbound_md5_hash.constprop.41+0x44/0x160
tcp_v6_do_rcv+0x181/0x3e0
tcp_v6_rcv+0xc65/0xcb0
ip6_protocol_deliver_rcu+0xbd/0x450
ip6_input_finish+0x11/0x20
ip6_input+0xb5/0xc0
ip6_sublist_rcv_finish+0x37/0x50
ip6_sublist_rcv+0x1dc/0x270
ipv6_list_rcv+0x113/0x140
__netif_receive_skb_list_core+0x1a0/0x210
netif_receive_skb_list_internal+0x186/0x2a0
gro_normal_list.part.170+0x19/0x40
napi_complete_done+0x65/0x150
mlx5e_napi_poll+0x1ae/0x680
__napi_poll+0x25/0x120
net_rx_action+0x11e/0x280
__do_softirq+0xbb/0x271
irq_exit_rcu+0x97/0xa0
common_interrupt+0x7f/0xa0
</IRQ>
asm_common_interrupt+0x1e/0x40
RIP: 0010:bpf_prog_1835a9241238291a_tw_egress+0x5/0xbac
? __cgroup_bpf_run_filter_skb+0x378/0x4e0
? do_softirq+0x34/0x70
? ip6_finish_output2+0x266/0x590
? ip6_finish_output+0x66/0xa0
? ip6_output+0x6c/0x130
? ip6_xmit+0x279/0x550
? ip6_dst_check+0x61/0xd0
[...]
Using drgn [0] to dump the percpu buffer contents showed that on this CPU
slot 0 is still available, but slots 1-7 are occupied and those tasks in
slots 1-7 mostly don't exist any more. So we might have issues in
bpf_cgroup_storage_unset().
Further debugging confirmed that there is a bug in bpf_cgroup_storage_unset().
Currently, it tries to unset "current" slot with searching from the start.
So the following sequence is possible:
1. A task is running and claims slot 0
2. Running BPF program is done, and it checked slot 0 has the "task"
and ready to reset it to NULL (not yet).
3. An interrupt happens, another BPF program runs and it claims slot 1
with the *same* task.
4. The unset() in interrupt context releases slot 0 since it matches "task".
5. Interrupt is done, the task in process context reset slot 0.
At the end, slot 1 is not reset and the same process can continue to occupy
slots 2-7 and finally, when the above step 1-5 is repeated again, step 3 BPF
program won't be able to claim an empty slot and a warning will be issued.
To fix the issue, for unset() function, we should traverse from the last slot
to the first. This way, the above issue can be avoided.
The same reverse traversal should also be done in bpf_get_local_storage() helper
itself. Otherwise, incorrect local storage may be returned to BPF program.
[0] https://github.com/osandov/drgn
Fixes: b910eaaaa4b8 ("bpf: Fix NULL pointer dereference in bpf_get_local_storage() helper")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210810010413.1976277-1-yhs@fb.com
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Back then, commit 96ae52279594 ("bpf: Add bpf_probe_write_user BPF helper
to be called in tracers") added the bpf_probe_write_user() helper in order
to allow to override user space memory. Its original goal was to have a
facility to "debug, divert, and manipulate execution of semi-cooperative
processes" under CAP_SYS_ADMIN. Write to kernel was explicitly disallowed
since it would otherwise tamper with its integrity.
One use case was shown in cf9b1199de27 ("samples/bpf: Add test/example of
using bpf_probe_write_user bpf helper") where the program DNATs traffic
at the time of connect(2) syscall, meaning, it rewrites the arguments to
a syscall while they're still in userspace, and before the syscall has a
chance to copy the argument into kernel space. These days we have better
mechanisms in BPF for achieving the same (e.g. for load-balancers), but
without having to write to userspace memory.
Of course the bpf_probe_write_user() helper can also be used to abuse
many other things for both good or bad purpose. Outside of BPF, there is
a similar mechanism for ptrace(2) such as PTRACE_PEEK{TEXT,DATA} and
PTRACE_POKE{TEXT,DATA}, but would likely require some more effort.
Commit 96ae52279594 explicitly dedicated the helper for experimentation
purpose only. Thus, move the helper's availability behind a newly added
LOCKDOWN_BPF_WRITE_USER lockdown knob so that the helper is disabled under
the "integrity" mode. More fine-grained control can be implemented also
from LSM side with this change.
Fixes: 96ae52279594 ("bpf: Add bpf_probe_write_user BPF helper to be called in tracers")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
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It's CONFIG_DEBUG_RT_MUTEXES not CONFIG_DEBUG_RT_MUTEX.
Fixes: f7efc4799f81 ("locking/rtmutex: Inline chainwalk depth check")
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210731123011.4555-1-thunder.leizhen@huawei.com
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fix from Tejun Heo:
"One commit to fix a possible A-A deadlock around u64_stats_sync on
32bit machines caused by updating it without disabling IRQ when it may
be read from IRQ context"
* 'for-5.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: rstat: fix A-A deadlock on 32bit around u64_stats_sync
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commit f9c82a4ea89c3 ("Increase size of ucounts to atomic_long_t")
changed the data type of ucounts/ucounts_max to long, but missed to
adjust a few other places. This is noticeable on big endian platforms
from user space because the /proc/sys/user/max_*_names files all
contain 0.
v4 - Made the min and max constants long so the sysctl values
are actually settable on little endian machines.
-- EWB
Fixes: f9c82a4ea89c ("Increase size of ucounts to atomic_long_t")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Acked-by: Alexey Gladkov <legion@kernel.org>
v1: https://lkml.kernel.org/r/20210721115800.910778-1-svens@linux.ibm.com
v2: https://lkml.kernel.org/r/20210721125233.1041429-1-svens@linux.ibm.com
v3: https://lkml.kernel.org/r/20210730062854.3601635-1-svens@linux.ibm.com
Link: https://lkml.kernel.org/r/8735rijqlv.fsf_-_@disp2133
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
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Rename LOCKDOWN_BPF_READ into LOCKDOWN_BPF_READ_KERNEL so we have naming
more consistent with a LOCKDOWN_BPF_WRITE_USER option that we are adding.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Thomas Gleixner:
"A single timer fix:
- Prevent a memory ordering issue in the timer expiry code which
makes it possible to observe falsely that the callback has been
executed already while that's not the case, which violates the
guarantee of del_timer_sync()"
* tag 'timers-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timers: Move clearing of base::timer_running under base:: Lock
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Thomas Gleixner:
"A single scheduler fix:
- Prevent a double enqueue caused by rt_effective_prio() being
invoked twice in __sched_setscheduler()"
* tag 'sched-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/rt: Fix double enqueue caused by rt_effective_prio
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Thomas Gleixner:
"A set of perf fixes:
- Correct the permission checks for perf event which send SIGTRAP to
a different process and clean up that code to be more readable.
- Prevent an out of bound MSR access in the x86 perf code which
happened due to an incomplete limiting to the actually available
hardware counters.
- Prevent access to the AMD64_EVENTSEL_HOSTONLY bit when running
inside a guest.
- Handle small core counter re-enabling correctly by issuing an ACK
right before reenabling it to prevent a stale PEBS record being
kept around"
* tag 'perf-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel: Apply mid ACK for small core
perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest
perf/x86: Fix out of bound MSR access
perf: Refactor permissions check into perf_check_permission()
perf: Fix required permissions if sigtrap is requested
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Daniel Borkmann says:
====================
pull-request: bpf 2021-08-07
The following pull-request contains BPF updates for your *net* tree.
We've added 4 non-merge commits during the last 9 day(s) which contain
a total of 4 files changed, 8 insertions(+), 7 deletions(-).
The main changes are:
1) Fix integer overflow in htab's lookup + delete batch op, from Tatsuhiko Yasumatsu.
2) Fix invalid fd 0 close in libbpf if BTF parsing failed, from Daniel Xu.
3) Fix libbpf feature probe for BPF_PROG_TYPE_CGROUP_SOCKOPT, from Robin Gögge.
4) Fix minor libbpf doc warning regarding code-block language, from Randy Dunlap.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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In __htab_map_lookup_and_delete_batch(), hash buckets are iterated
over to count the number of elements in each bucket (bucket_size).
If bucket_size is large enough, the multiplication to calculate
kvmalloc() size could overflow, resulting in out-of-bounds write
as reported by KASAN:
[...]
[ 104.986052] BUG: KASAN: vmalloc-out-of-bounds in __htab_map_lookup_and_delete_batch+0x5ce/0xb60
[ 104.986489] Write of size 4194224 at addr ffffc9010503be70 by task crash/112
[ 104.986889]
[ 104.987193] CPU: 0 PID: 112 Comm: crash Not tainted 5.14.0-rc4 #13
[ 104.987552] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[ 104.988104] Call Trace:
[ 104.988410] dump_stack_lvl+0x34/0x44
[ 104.988706] print_address_description.constprop.0+0x21/0x140
[ 104.988991] ? __htab_map_lookup_and_delete_batch+0x5ce/0xb60
[ 104.989327] ? __htab_map_lookup_and_delete_batch+0x5ce/0xb60
[ 104.989622] kasan_report.cold+0x7f/0x11b
[ 104.989881] ? __htab_map_lookup_and_delete_batch+0x5ce/0xb60
[ 104.990239] kasan_check_range+0x17c/0x1e0
[ 104.990467] memcpy+0x39/0x60
[ 104.990670] __htab_map_lookup_and_delete_batch+0x5ce/0xb60
[ 104.990982] ? __wake_up_common+0x4d/0x230
[ 104.991256] ? htab_of_map_free+0x130/0x130
[ 104.991541] bpf_map_do_batch+0x1fb/0x220
[...]
In hashtable, if the elements' keys have the same jhash() value, the
elements will be put into the same bucket. By putting a lot of elements
into a single bucket, the value of bucket_size can be increased to
trigger the integer overflow.
Triggering the overflow is possible for both callers with CAP_SYS_ADMIN
and callers without CAP_SYS_ADMIN.
It will be trivial for a caller with CAP_SYS_ADMIN to intentionally
reach this overflow by enabling BPF_F_ZERO_SEED. As this flag will set
the random seed passed to jhash() to 0, it will be easy for the caller
to prepare keys which will be hashed into the same value, and thus put
all the elements into the same bucket.
If the caller does not have CAP_SYS_ADMIN, BPF_F_ZERO_SEED cannot be
used. However, it will be still technically possible to trigger the
overflow, by guessing the random seed value passed to jhash() (32bit)
and repeating the attempt to trigger the overflow. In this case,
the probability to trigger the overflow will be low and will take
a very long time.
Fix the integer overflow by calling kvmalloc_array() instead of
kvmalloc() to allocate memory.
Fixes: 057996380a42 ("bpf: Add batch ops to all htab bpf map")
Signed-off-by: Tatsuhiko Yasumatsu <th.yasumatsu@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210806150419.109658-1-th.yasumatsu@gmail.com
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"Fix tracepoint race between static_call and callback data
As callbacks to a tracepoint are paired with the data that is passed
in when the callback is registered to the tracepoint, it must have
that data passed to the callback when the tracepoint is triggered,
else bad things will happen. To keep the two together, they are both
assigned to a tracepoint structure and added to an array. The
tracepoint call site will dereference the structure (via RCU) and call
the callback in that structure along with the data in that structure.
This keeps the callback and data tightly coupled.
Because of the overhead that retpolines have on tracepoint callbacks,
if there's only one callback attached to a tracepoint (a common case),
then it is called via a static call (code modified to do a direct call
instead of an indirect call). But to implement this, the data had to
be decoupled from the callback, as now the callback is implemented via
a direct call from the static call and not an indirect call from the
dereferenced structure.
Note, the static call only calls a callback used when there's a single
callback attached to the tracepoint. If more than one callback is
attached to the same tracepoint, then the static call will call an
iterator function that goes back to dereferencing the structure
keeping the callback and its data tightly coupled again.
Issues can arise when going from 0 callbacks to one, as the static
call is assigned to the callback, and it must take care that the data
passed to it is loaded before the static call calls the callback.
Going from 1 to 2 callbacks is not an issue, as long as the static
call is updated to the iterator before the tracepoint structure array
is updated via RCU. Going from 2 to more or back down to 2 is not an
issue as the iterator can handle all theses cases. But going from 2 to
1, care must be taken as the static call is now calling a callback and
the data that is loaded must be the data for that callback.
Care was taken to ensure the callback and data would be in-sync, but
after a bug was reported, it became clear that not enough was done to
make sure that was the case. These changes address this.
The first change is to compare the old and new data instead of the old
and new callback, as it's the data that can corrupt the callback, even
if the callback is the same (something getting freed).
The next change is to convert these transitions into states, to make
it easier to know when a synchronization is needed, and to perform
those synchronizations. The problem with this patch is that it slows
down disabling all events from under a second, to making it take over
10 seconds to do the same work. But that is addressed in the final
patch.
The final patch uses the RCU state functions to keep track of the RCU
state between the transitions, and only needs to perform the
synchronization if an RCU synchronization hasn't been done already.
This brings the performance of disabling all events back to its
original value. That's because no synchronization is required between
disabling tracepoints but is required when enabling a tracepoint after
its been disabled. If an RCU synchronization happens after the
tracepoint is disabled, and before it is re-enabled, there's no need
to do the synchronization again.
Both the second and third patch have subtle complexities that they are
separated into two patches. But because the second patch causes such a
regression in performance, the third patch adds a "Fixes" tag to the
second patch, such that the two must be backported together and not
just the second patch"
* tag 'trace-v5.14-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracepoint: Use rcu get state and cond sync for static call updates
tracepoint: Fix static call function vs data state mismatch
tracepoint: static call: Compare data on transition from 2->1 callees
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State transitions from 1->0->1 and N->2->1 callbacks require RCU
synchronization. Rather than performing the RCU synchronization every
time the state change occurs, which is quite slow when many tracepoints
are registered in batch, instead keep a snapshot of the RCU state on the
most recent transitions which belong to a chain, and conditionally wait
for a grace period on the last transition of the chain if one g.p. has
not elapsed since the last snapshot.
This applies to both RCU and SRCU.
This brings the performance regression caused by commit 231264d6927f
("Fix: tracepoint: static call function vs data state mismatch") back to
what it was originally.
Before this commit:
# trace-cmd start -e all
# time trace-cmd start -p nop
real 0m10.593s
user 0m0.017s
sys 0m0.259s
After this commit:
# trace-cmd start -e all
# time trace-cmd start -p nop
real 0m0.878s
user 0m0.000s
sys 0m0.103s
Link: https://lkml.kernel.org/r/20210805192954.30688-1-mathieu.desnoyers@efficios.com
Link: https://lore.kernel.org/io-uring/4ebea8f0-58c9-e571-fd30-0ce4f6f09c70@samba.org/
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Stefan Metzmacher <metze@samba.org>
Fixes: 231264d6927f ("Fix: tracepoint: static call function vs data state mismatch")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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