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The behavior of the test_dummy_encryption mount option is that when a
new file (or directory or symlink) is created in an unencrypted
directory, it's automatically encrypted using a dummy encryption policy.
That's it; in particular, the encryption (or lack thereof) of existing
files (or directories or symlinks) doesn't change.
Unfortunately the implementation of test_dummy_encryption is a bit weird
and confusing. When test_dummy_encryption is enabled and a file is
being created in an unencrypted directory, we set up an encryption key
(->i_crypt_info) for the directory. This isn't actually used to do any
encryption, however, since the directory is still unencrypted! Instead,
->i_crypt_info is only used for inheriting the encryption policy.
One consequence of this is that the filesystem ends up providing a
"dummy context" (policy + nonce) instead of a "dummy policy". In
commit ed318a6cc0b6 ("fscrypt: support test_dummy_encryption=v2"), I
mistakenly thought this was required. However, actually the nonce only
ends up being used to derive a key that is never used.
Another consequence of this implementation is that it allows for
'inode->i_crypt_info != NULL && !IS_ENCRYPTED(inode)', which is an edge
case that can be forgotten about. For example, currently
FS_IOC_GET_ENCRYPTION_POLICY on an unencrypted directory may return the
dummy encryption policy when the filesystem is mounted with
test_dummy_encryption. That seems like the wrong thing to do, since
again, the directory itself is not actually encrypted.
Therefore, switch to a more logical and maintainable implementation
where the dummy encryption policy inheritance is done without setting up
keys for unencrypted directories. This involves:
- Adding a function fscrypt_policy_to_inherit() which returns the
encryption policy to inherit from a directory. This can be a real
policy, a dummy policy, or no policy.
- Replacing struct fscrypt_dummy_context, ->get_dummy_context(), etc.
with struct fscrypt_dummy_policy, ->get_dummy_policy(), etc.
- Making fscrypt_fname_encrypted_size() take an fscrypt_policy instead
of an inode.
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-13-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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In preparation for moving the logic for "get the encryption policy
inherited by new files in this directory" to a single place, make
fscrypt_prepare_symlink() a regular function rather than an inline
function that wraps __fscrypt_prepare_symlink().
This way, the new function fscrypt_policy_to_inherit() won't need to be
exported to filesystems.
Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-12-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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The fscrypt UAPI header defines fscrypt_policy to fscrypt_policy_v1,
for source compatibility with old userspace programs.
Internally, the kernel doesn't want that compatibility definition.
Instead, fscrypt_private.h #undefs it and re-defines it to a union.
That works for now. However, in order to add
fscrypt_operations::get_dummy_policy(), we'll need to forward declare
'union fscrypt_policy' in include/linux/fscrypt.h. That would cause
build errors because "fscrypt_policy" is used in ioctl numbers.
To avoid this, modify the UAPI header to make the fscrypt_policy
compatibility definition conditional on !__KERNEL__, and make the ioctls
use fscrypt_policy_v1 instead of fscrypt_policy.
Note that this doesn't change the actual ioctl numbers.
Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-11-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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fscrypt_get_encryption_info() has never actually been safe to call in a
context that needs GFP_NOFS, since it calls crypto_alloc_skcipher().
crypto_alloc_skcipher() isn't GFP_NOFS-safe, even if called under
memalloc_nofs_save(). This is because it may load kernel modules, and
also because it internally takes crypto_alg_sem. Other tasks can do
GFP_KERNEL allocations while holding crypto_alg_sem for write.
The use of fscrypt_init_mutex isn't GFP_NOFS-safe either.
So, stop pretending that fscrypt_get_encryption_info() is nofs-safe.
I.e., when it allocates memory, just use GFP_KERNEL instead of GFP_NOFS.
Note, another reason to do this is that GFP_NOFS is deprecated in favor
of using memalloc_nofs_save() in the proper places.
Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-10-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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Now that all filesystems have been converted to use
fscrypt_prepare_new_inode(), the encryption key for new symlink inodes
is now already set up whenever we try to encrypt the symlink target.
Enforce this rather than try to set up the key again when it may be too
late to do so safely.
Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-9-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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Now that all filesystems have been converted to use
fscrypt_prepare_new_inode() and fscrypt_set_context(),
fscrypt_inherit_context() is no longer used. Remove it.
Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-8-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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Now that a fscrypt_info may be set up for inodes that are currently
being created and haven't yet had an inode number assigned, avoid
logging confusing messages about "inode 0".
Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-7-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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Convert ubifs to use the new functions fscrypt_prepare_new_inode() and
fscrypt_set_context().
Unlike ext4 and f2fs, this doesn't appear to fix any deadlock bug. But
it does shorten the code slightly and get all filesystems using the same
helper functions, so that fscrypt_inherit_context() can be removed.
It also fixes an incorrect error code where ubifs returned EPERM instead
of the expected ENOKEY.
Link: https://lore.kernel.org/r/20200917041136.178600-6-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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Convert f2fs to use the new functions fscrypt_prepare_new_inode() and
fscrypt_set_context(). This avoids calling
fscrypt_get_encryption_info() from under f2fs_lock_op(), which can
deadlock because fscrypt_get_encryption_info() isn't GFP_NOFS-safe.
For more details about this problem, see the earlier patch
"fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()".
This also fixes a f2fs-specific deadlock when the filesystem is mounted
with '-o test_dummy_encryption' and a file is created in an unencrypted
directory other than the root directory:
INFO: task touch:207 blocked for more than 30 seconds.
Not tainted 5.9.0-rc4-00099-g729e3d0919844 #2
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:touch state:D stack: 0 pid: 207 ppid: 167 flags:0x00000000
Call Trace:
[...]
lock_page include/linux/pagemap.h:548 [inline]
pagecache_get_page+0x25e/0x310 mm/filemap.c:1682
find_or_create_page include/linux/pagemap.h:348 [inline]
grab_cache_page include/linux/pagemap.h:424 [inline]
f2fs_grab_cache_page fs/f2fs/f2fs.h:2395 [inline]
f2fs_grab_cache_page fs/f2fs/f2fs.h:2373 [inline]
__get_node_page.part.0+0x39/0x2d0 fs/f2fs/node.c:1350
__get_node_page fs/f2fs/node.c:35 [inline]
f2fs_get_node_page+0x2e/0x60 fs/f2fs/node.c:1399
read_inline_xattr+0x88/0x140 fs/f2fs/xattr.c:288
lookup_all_xattrs+0x1f9/0x2c0 fs/f2fs/xattr.c:344
f2fs_getxattr+0x9b/0x160 fs/f2fs/xattr.c:532
f2fs_get_context+0x1e/0x20 fs/f2fs/super.c:2460
fscrypt_get_encryption_info+0x9b/0x450 fs/crypto/keysetup.c:472
fscrypt_inherit_context+0x2f/0xb0 fs/crypto/policy.c:640
f2fs_init_inode_metadata+0xab/0x340 fs/f2fs/dir.c:540
f2fs_add_inline_entry+0x145/0x390 fs/f2fs/inline.c:621
f2fs_add_dentry+0x31/0x80 fs/f2fs/dir.c:757
f2fs_do_add_link+0xcd/0x130 fs/f2fs/dir.c:798
f2fs_add_link fs/f2fs/f2fs.h:3234 [inline]
f2fs_create+0x104/0x290 fs/f2fs/namei.c:344
lookup_open.isra.0+0x2de/0x500 fs/namei.c:3103
open_last_lookups+0xa9/0x340 fs/namei.c:3177
path_openat+0x8f/0x1b0 fs/namei.c:3365
do_filp_open+0x87/0x130 fs/namei.c:3395
do_sys_openat2+0x96/0x150 fs/open.c:1168
[...]
That happened because f2fs_add_inline_entry() locks the directory
inode's page in order to add the dentry, then f2fs_get_context() tries
to lock it recursively in order to read the encryption xattr. This
problem is specific to "test_dummy_encryption" because normally the
directory's fscrypt_info would be set up prior to
f2fs_add_inline_entry() in order to encrypt the new filename.
Regardless, the new design fixes this test_dummy_encryption deadlock as
well as potential deadlocks with fs reclaim, by setting up any needed
fscrypt_info structs prior to taking so many locks.
The test_dummy_encryption deadlock was reported by Daniel Rosenberg.
Reported-by: Daniel Rosenberg <drosen@google.com>
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-5-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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Convert ext4 to use the new functions fscrypt_prepare_new_inode() and
fscrypt_set_context(). This avoids calling
fscrypt_get_encryption_info() from within a transaction, which can
deadlock because fscrypt_get_encryption_info() isn't GFP_NOFS-safe.
For more details about this problem, see the earlier patch
"fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()".
Link: https://lore.kernel.org/r/20200917041136.178600-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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To compute a new inode's xattr credits, we need to know whether the
inode will be encrypted or not. When we switch to use the new helper
function fscrypt_prepare_new_inode(), we won't find out whether the
inode will be encrypted until slightly later than is currently the case.
That will require moving the code block that computes the xattr credits.
To make this easier and reduce the length of __ext4_new_inode(), move
this code block into a new function ext4_xattr_credits_for_new_inode().
Link: https://lore.kernel.org/r/20200917041136.178600-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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fscrypt_get_encryption_info() is intended to be GFP_NOFS-safe. But
actually it isn't, since it uses functions like crypto_alloc_skcipher()
which aren't GFP_NOFS-safe, even when called under memalloc_nofs_save().
Therefore it can deadlock when called from a context that needs
GFP_NOFS, e.g. during an ext4 transaction or between f2fs_lock_op() and
f2fs_unlock_op(). This happens when creating a new encrypted file.
We can't fix this by just not setting up the key for new inodes right
away, since new symlinks need their key to encrypt the symlink target.
So we need to set up the new inode's key before starting the
transaction. But just calling fscrypt_get_encryption_info() earlier
doesn't work, since it assumes the encryption context is already set,
and the encryption context can't be set until the transaction.
The recently proposed fscrypt support for the ceph filesystem
(https://lkml.kernel.org/linux-fscrypt/20200821182813.52570-1-jlayton@kernel.org/T/#u)
will have this same ordering problem too, since ceph will need to
encrypt new symlinks before setting their encryption context.
Finally, f2fs can deadlock when the filesystem is mounted with
'-o test_dummy_encryption' and a new file is created in an existing
unencrypted directory. Similarly, this is caused by holding too many
locks when calling fscrypt_get_encryption_info().
To solve all these problems, add new helper functions:
- fscrypt_prepare_new_inode() sets up a new inode's encryption key
(fscrypt_info), using the parent directory's encryption policy and a
new random nonce. It neither reads nor writes the encryption context.
- fscrypt_set_context() persists the encryption context of a new inode,
using the information from the fscrypt_info already in memory. This
replaces fscrypt_inherit_context().
Temporarily keep fscrypt_inherit_context() around until all filesystems
have been converted to use fscrypt_set_context().
Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200917041136.178600-2-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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When an encryption policy has the IV_INO_LBLK_32 flag set, the IV
generation method involves hashing the inode number. This is different
from fscrypt's other IV generation methods, where the inode number is
either not used at all or is included directly in the IVs.
Therefore, in principle IV_INO_LBLK_32 can work with any length inode
number. However, currently fscrypt gets the inode number from
inode::i_ino, which is 'unsigned long'. So currently the implementation
limit is actually 32 bits (like IV_INO_LBLK_64), since longer inode
numbers will have been truncated by the VFS on 32-bit platforms.
Fix fscrypt_supported_v2_policy() to enforce the correct limit.
This doesn't actually matter currently, since only ext4 and f2fs support
IV_INO_LBLK_32, and they both only support 32-bit inode numbers. But we
might as well fix it in case it matters in the future.
Ideally inode::i_ino would instead be made 64-bit, but for now it's not
needed. (Note, this limit does *not* prevent filesystems with 64-bit
inode numbers from adding fscrypt support, since IV_INO_LBLK_* support
is optional and is useful only on certain hardware.)
Fixes: e3b1078bedd3 ("fscrypt: add support for IV_INO_LBLK_32 policies")
Reported-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200824203841.1707847-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20200810142139.487631-1-jlayton@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
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Pull more io_uring fixes from Jens Axboe:
"Two followup fixes. One is fixing a regression from this merge window,
the other is two commits fixing cancelation of deferred requests.
Both have gone through full testing, and both spawned a few new
regression test additions to liburing.
- Don't play games with const, properly store the output iovec and
assign it as needed.
- Deferred request cancelation fix (Pavel)"
* tag 'io_uring-5.9-2020-09-06' of git://git.kernel.dk/linux-block:
io_uring: fix linked deferred ->files cancellation
io_uring: fix cancel of deferred reqs with ->files
io_uring: fix explicit async read/write mapping for large segments
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git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu
Pull iommu fixes from Joerg Roedel:
- three Intel VT-d fixes to fix address handling on 32bit, fix a NULL
pointer dereference bug and serialize a hardware register access as
required by the VT-d spec.
- two patches for AMD IOMMU to force AMD GPUs into translation mode
when memory encryption is active and disallow using IOMMUv2
functionality. This makes the AMDGPU driver work when memory
encryption is active.
- two more fixes for AMD IOMMU to fix updating the Interrupt Remapping
Table Entries.
- MAINTAINERS file update for the Qualcom IOMMU driver.
* tag 'iommu-fixes-v5.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
iommu/vt-d: Handle 36bit addressing for x86-32
iommu/amd: Do not use IOMMUv2 functionality when SME is active
iommu/amd: Do not force direct mapping when SME is active
iommu/amd: Use cmpxchg_double() when updating 128-bit IRTE
iommu/amd: Restore IRTE.RemapEn bit after programming IRTE
iommu/vt-d: Fix NULL pointer dereference in dev_iommu_priv_set()
iommu/vt-d: Serialize IOMMU GCMD register modifications
MAINTAINERS: Update QUALCOMM IOMMU after Arm SMMU drivers move
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
- more generic entry code ABI fallout
- debug register handling bugfixes
- fix vmalloc mappings on 32-bit kernels
- kprobes instrumentation output fix on 32-bit kernels
- fix over-eager WARN_ON_ONCE() on !SMAP hardware
- NUMA debugging fix
- fix Clang related crash on !RETPOLINE kernels
* tag 'x86-urgent-2020-09-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/entry: Unbreak 32bit fast syscall
x86/debug: Allow a single level of #DB recursion
x86/entry: Fix AC assertion
tracing/kprobes, x86/ptrace: Fix regs argument order for i386
x86, fakenuma: Fix invalid starting node ID
x86/mm/32: Bring back vmalloc faulting on x86_32
x86/cmdline: Disable jump tables for cmdline.c
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git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
"A small series for fixing a problem with Xen PVH guests when running
as backends (e.g. as dom0).
Mapping other guests' memory is now working via ZONE_DEVICE, thus not
requiring to abuse the memory hotplug functionality for that purpose"
* tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: add helpers to allocate unpopulated memory
memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERIC
xen/balloon: add header guard
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While looking for ->files in ->defer_list, consider that requests there
may actually be links.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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While trying to cancel requests with ->files, it also should look for
requests in ->defer_list, otherwise it might end up hanging a thread.
Cancel all requests in ->defer_list up to the last request there with
matching ->files, that's needed to follow drain ordering semantics.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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'clang-format-for-linus-v5.9-rc4' and 'compiler-attributes-for-linus-v5.9-rc4' of git://github.com/ojeda/linux
Pull misc fixes from Miguel Ojeda:
"A trivial patch for auxdisplay:
- Replace HTTP links with HTTPS ones (Alexander A. Klimov)
The usual clang-format trivial update:
- Update with the latest for_each macro list (Miguel Ojeda)
And Luc requested me to pick a sparse fix on my queue, so here it goes
along with other two trivial Compiler Attributes ones (also from Luc).
- sparse: use static inline for __chk_{user,io}_ptr() (Luc Van
Oostenryck)
- Compiler Attributes: fix comment concerning GCC 4.6 (Luc Van
Oostenryck)
- Compiler Attributes: remove comment about sparse not supporting
__has_attribute (Luc Van Oostenryck)"
* tag 'auxdisplay-for-linus-v5.9-rc4' of git://github.com/ojeda/linux:
auxdisplay: Replace HTTP links with HTTPS ones
* tag 'clang-format-for-linus-v5.9-rc4' of git://github.com/ojeda/linux:
clang-format: Update with the latest for_each macro list
* tag 'compiler-attributes-for-linus-v5.9-rc4' of git://github.com/ojeda/linux:
sparse: use static inline for __chk_{user,io}_ptr()
Compiler Attributes: fix comment concerning GCC 4.6
Compiler Attributes: remove comment about sparse not supporting __has_attribute
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git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Pull ARC fixes from Vineet Gupta:
- HSDK-4xd Dev system: perf driver updates for sampling interrupt
- HSDK* Dev System: Ethernet broken [Evgeniy Didin]
- HIGHMEM broken (2 memory banks) [Mike Rapoport]
- show_regs() rewrite once and for all
- Other minor fixes
* tag 'arc-5.9-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
ARC: [plat-hsdk]: Switch ethernet phy-mode to rgmii-id
arc: fix memory initialization for systems with two memory banks
irqchip/eznps: Fix build error for !ARC700 builds
ARC: show_regs: fix r12 printing and simplify
ARC: HSDK: wireup perf irq
ARC: perf: don't bail setup if pct irq missing in device-tree
ARC: pgalloc.h: delete a duplicated word + other fixes
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Merge misc fixes from Andrew Morton:
"19 patches.
Subsystems affected by this patch series: MAINTAINERS, ipc, fork,
checkpatch, lib, and mm (memcg, slub, pagemap, madvise, migration,
hugetlb)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
include/linux/log2.h: add missing () around n in roundup_pow_of_two()
mm/khugepaged.c: fix khugepaged's request size in collapse_file
mm/hugetlb: fix a race between hugetlb sysctl handlers
mm/hugetlb: try preferred node first when alloc gigantic page from cma
mm/migrate: preserve soft dirty in remove_migration_pte()
mm/migrate: remove unnecessary is_zone_device_page() check
mm/rmap: fixup copying of soft dirty and uffd ptes
mm/migrate: fixup setting UFFD_WP flag
mm: madvise: fix vma user-after-free
checkpatch: fix the usage of capture group ( ... )
fork: adjust sysctl_max_threads definition to match prototype
ipc: adjust proc_ipc_sem_dointvec definition to match prototype
mm: track page table modifications in __apply_to_page_range()
MAINTAINERS: IA64: mark Status as Odd Fixes only
MAINTAINERS: add LLVM maintainers
MAINTAINERS: update Cavium/Marvell entries
mm: slub: fix conversion of freelist_corrupted()
mm: memcg: fix memcg reclaim soft lockup
memcg: fix use-after-free in uncharge_batch
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Otherwise gcc generates warnings if the expression is complicated.
Fixes: 312a0c170945 ("[PATCH] LOG2: Alter roundup_pow_of_two() so that it can use a ilog2() on a constant")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/0-v1-8a2697e3c003+41165-log_brackets_jgg@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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collapse_file() in khugepaged passes PAGE_SIZE as the number of pages to
be read to page_cache_sync_readahead(). The intent was probably to read
a single page. Fix it to use the number of pages to the end of the
window instead.
Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Eric Biggers <ebiggers@google.com>
Link: https://lkml.kernel.org/r/20200903140844.14194-2-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There is a race between the assignment of `table->data` and write value
to the pointer of `table->data` in the __do_proc_doulongvec_minmax() on
the other thread.
CPU0: CPU1:
proc_sys_write
hugetlb_sysctl_handler proc_sys_call_handler
hugetlb_sysctl_handler_common hugetlb_sysctl_handler
table->data = &tmp; hugetlb_sysctl_handler_common
table->data = &tmp;
proc_doulongvec_minmax
do_proc_doulongvec_minmax sysctl_head_finish
__do_proc_doulongvec_minmax unuse_table
i = table->data;
*i = val; // corrupt CPU1's stack
Fix this by duplicating the `table`, and only update the duplicate of
it. And introduce a helper of proc_hugetlb_doulongvec_minmax() to
simplify the code.
The following oops was seen:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
Code: Bad RIP value.
...
Call Trace:
? set_max_huge_pages+0x3da/0x4f0
? alloc_pool_huge_page+0x150/0x150
? proc_doulongvec_minmax+0x46/0x60
? hugetlb_sysctl_handler_common+0x1c7/0x200
? nr_hugepages_store+0x20/0x20
? copy_fd_bitmaps+0x170/0x170
? hugetlb_sysctl_handler+0x1e/0x20
? proc_sys_call_handler+0x2f1/0x300
? unregister_sysctl_table+0xb0/0xb0
? __fd_install+0x78/0x100
? proc_sys_write+0x14/0x20
? __vfs_write+0x4d/0x90
? vfs_write+0xef/0x240
? ksys_write+0xc0/0x160
? __ia32_sys_read+0x50/0x50
? __close_fd+0x129/0x150
? __x64_sys_write+0x43/0x50
? do_syscall_64+0x6c/0x200
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: e5ff215941d5 ("hugetlb: multiple hstates for multiple page sizes")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20200828031146.43035-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Since commit cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic
hugepages using cma"), the gigantic page would be allocated from node
which is not the preferred node, although there are pages available from
that node. The reason is that the nid parameter has been ignored in
alloc_gigantic_page().
Besides, the __GFP_THISNODE also need be checked if user required to
alloc only from the preferred node.
After this patch, the preferred node is tried first before other allowed
nodes, and don't try to allocate from other nodes if __GFP_THISNODE is
specified. If user don't specify the preferred node, the current node
will be used as preferred node, which makes sure consistent behavior of
allocating gigantic and non-gigantic hugetlb page.
Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Link: https://lkml.kernel.org/r/20200902025016.697260-1-lixinhai.lxh@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The code to remove a migration PTE and replace it with a device private
PTE was not copying the soft dirty bit from the migration entry. This
could lead to page contents not being marked dirty when faulting the page
back from device private memory.
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Link: https://lkml.kernel.org/r/20200831212222.22409-3-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "mm/migrate: preserve soft dirty in remove_migration_pte()".
I happened to notice this from code inspection after seeing Alistair
Popple's patch ("mm/rmap: Fixup copying of soft dirty and uffd ptes").
This patch (of 2):
The check for is_zone_device_page() and is_device_private_page() is
unnecessary since the latter is sufficient to determine if the page is a
device private page. Simplify the code for easier reading.
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Link: https://lkml.kernel.org/r/20200831212222.22409-1-rcampbell@nvidia.com
Link: https://lkml.kernel.org/r/20200831212222.22409-2-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
During memory migration a pte is temporarily replaced with a migration
swap pte. Some pte bits from the existing mapping such as the soft-dirty
and uffd write-protect bits are preserved by copying these to the
temporary migration swap pte.
However these bits are not stored at the same location for swap and
non-swap ptes. Therefore testing these bits requires using the
appropriate helper function for the given pte type.
Unfortunately several code locations were found where the wrong helper
function is being used to test soft_dirty and uffd_wp bits which leads to
them getting incorrectly set or cleared during page-migration.
Fix these by using the correct tests based on pte type.
Fixes: a5430dda8a3a ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
Fixes: 8c3328f1f36a ("mm/migrate: migrate_vma() unmap page from vma while collecting pages")
Fixes: f45ec5ff16a7 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Alistair Popple <alistair@popple.id.au>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200825064232.10023-2-alistair@popple.id.au
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Commit f45ec5ff16a75 ("userfaultfd: wp: support swap and page migration")
introduced support for tracking the uffd wp bit during page migration.
However the non-swap PTE variant was used to set the flag for zone device
private pages which are a type of swap page.
This leads to corruption of the swap offset if the original PTE has the
uffd_wp flag set.
Fixes: f45ec5ff16a75 ("userfaultfd: wp: support swap and page migration")
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Link: https://lkml.kernel.org/r/20200825064232.10023-1-alistair@popple.id.au
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The syzbot reported the below use-after-free:
BUG: KASAN: use-after-free in madvise_willneed mm/madvise.c:293 [inline]
BUG: KASAN: use-after-free in madvise_vma mm/madvise.c:942 [inline]
BUG: KASAN: use-after-free in do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145
Read of size 8 at addr ffff8880a6163eb0 by task syz-executor.0/9996
CPU: 0 PID: 9996 Comm: syz-executor.0 Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x18f/0x20d lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
madvise_willneed mm/madvise.c:293 [inline]
madvise_vma mm/madvise.c:942 [inline]
do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145
do_madvise mm/madvise.c:1169 [inline]
__do_sys_madvise mm/madvise.c:1171 [inline]
__se_sys_madvise mm/madvise.c:1169 [inline]
__x64_sys_madvise+0xd9/0x110 mm/madvise.c:1169
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Allocated by task 9992:
kmem_cache_alloc+0x138/0x3a0 mm/slab.c:3482
vm_area_alloc+0x1c/0x110 kernel/fork.c:347
mmap_region+0x8e5/0x1780 mm/mmap.c:1743
do_mmap+0xcf9/0x11d0 mm/mmap.c:1545
vm_mmap_pgoff+0x195/0x200 mm/util.c:506
ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Freed by task 9992:
kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693
remove_vma+0x132/0x170 mm/mmap.c:184
remove_vma_list mm/mmap.c:2613 [inline]
__do_munmap+0x743/0x1170 mm/mmap.c:2869
do_munmap mm/mmap.c:2877 [inline]
mmap_region+0x257/0x1780 mm/mmap.c:1716
do_mmap+0xcf9/0x11d0 mm/mmap.c:1545
vm_mmap_pgoff+0x195/0x200 mm/util.c:506
ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
It is because vma is accessed after releasing mmap_lock, but someone
else acquired the mmap_lock and the vma is gone.
Releasing mmap_lock after accessing vma should fix the problem.
Fixes: 692fe62433d4c ("mm: Handle MADV_WILLNEED through vfs_fadvise()")
Reported-by: syzbot+b90df26038d1d5d85c97@syzkaller.appspotmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: <stable@vger.kernel.org> [5.4+]
Link: https://lkml.kernel.org/r/20200816141204.162624-1-shy828301@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The usage of "capture group (...)" in the immediate condition after `&&`
results in `$1` being uninitialized. This issues a warning "Use of
uninitialized value $1 in regexp compilation at ./scripts/checkpatch.pl
line 2638".
I noticed this bug while running checkpatch on the set of commits from
v5.7 to v5.8-rc1 of the kernel on the commits with a diff content in
their commit message.
This bug was introduced in the script by commit e518e9a59ec3
("checkpatch: emit an error when there's a diff in a changelog"). It
has been in the script since then.
The author intended to store the match made by capture group in variable
`$1`. This should have contained the name of the file as `[\w/]+`
matched. However, this couldn't be accomplished due to usage of capture
group and `$1` in the same regular expression.
Fix this by placing the capture group in the condition before `&&`.
Thus, `$1` can be initialized to the text that capture group matches
thereby setting it to the desired and required value.
Fixes: e518e9a59ec3 ("checkpatch: emit an error when there's a diff in a changelog")
Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Joe Perches <joe@perches.com>
Link: https://lkml.kernel.org/r/20200714032352.f476hanaj2dlmiot@mrinalpandey
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Commit 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer. Adjust the
definition of sysctl_max_threads to match its prototype in
linux/sysctl.h which fixes the following sparse error/warning:
kernel/fork.c:3050:47: warning: incorrect type in argument 3 (different address spaces)
kernel/fork.c:3050:47: expected void *
kernel/fork.c:3050:47: got void [noderef] __user *buffer
kernel/fork.c:3036:5: error: symbol 'sysctl_max_threads' redeclared with different type (incompatible argument 3 (different address spaces)):
kernel/fork.c:3036:5: int extern [addressable] [signed] [toplevel] sysctl_max_threads( ... )
kernel/fork.c: note: in included file (through include/linux/key.h, include/linux/cred.h, include/linux/sched/signal.h, include/linux/sched/cputime.h):
include/linux/sysctl.h:242:5: note: previously declared as:
include/linux/sysctl.h:242:5: int extern [addressable] [signed] [toplevel] sysctl_max_threads( ... )
Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/20200825093647.24263-1-tklauser@distanz.ch
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Commit 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer. Adjust the
signature of proc_ipc_sem_dointvec to match ctl_table.proc_handler which
fixes the following sparse error/warning:
ipc/ipc_sysctl.c:94:47: warning: incorrect type in argument 3 (different address spaces)
ipc/ipc_sysctl.c:94:47: expected void *buffer
ipc/ipc_sysctl.c:94:47: got void [noderef] __user *buffer
ipc/ipc_sysctl.c:194:35: warning: incorrect type in initializer (incompatible argument 3 (different address spaces))
ipc/ipc_sysctl.c:194:35: expected int ( [usertype] *proc_handler )( ... )
ipc/ipc_sysctl.c:194:35: got int ( * )( ... )
Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler")
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/20200825105846.5193-1-tklauser@distanz.ch
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
__apply_to_page_range() is also used to change and/or allocate
page-table pages in the vmalloc area of the address space. Make sure
these changes get synchronized to other page-tables in the system by
calling arch_sync_kernel_mappings() when necessary.
The impact appears limited to x86-32, where apply_to_page_range may miss
updating the PMD. That leads to explosions in drivers like
BUG: unable to handle page fault for address: fe036000
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
*pde = 00000000
Oops: 0002 [#1] SMP
CPU: 3 PID: 1300 Comm: gem_concurrent_ Not tainted 5.9.0-rc1+ #16
Hardware name: /NUC6i3SYB, BIOS SYSKLi35.86A.0024.2015.1027.2142 10/27/2015
EIP: __execlists_context_alloc+0x132/0x2d0 [i915]
Code: 31 d2 89 f0 e8 2f 55 02 00 89 45 e8 3d 00 f0 ff ff 0f 87 11 01 00 00 8b 4d e8 03 4b 30 b8 5a 5a 5a 5a ba 01 00 00 00 8d 79 04 <c7> 01 5a 5a 5a 5a c7 81 fc 0f 00 00 5a 5a 5a 5a 83 e7 fc 29 f9 81
EAX: 5a5a5a5a EBX: f60ca000 ECX: fe036000 EDX: 00000001
ESI: f43b7340 EDI: fe036004 EBP: f6389cb8 ESP: f6389c9c
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010286
CR0: 80050033 CR2: fe036000 CR3: 2d361000 CR4: 001506d0
DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
DR6: fffe0ff0 DR7: 00000400
Call Trace:
execlists_context_alloc+0x10/0x20 [i915]
intel_context_alloc_state+0x3f/0x70 [i915]
__intel_context_do_pin+0x117/0x170 [i915]
i915_gem_do_execbuffer+0xcc7/0x2500 [i915]
i915_gem_execbuffer2_ioctl+0xcd/0x1f0 [i915]
drm_ioctl_kernel+0x8f/0xd0
drm_ioctl+0x223/0x3d0
__ia32_sys_ioctl+0x1ab/0x760
__do_fast_syscall_32+0x3f/0x70
do_fast_syscall_32+0x29/0x60
do_SYSENTER_32+0x15/0x20
entry_SYSENTER_32+0x9f/0xf2
EIP: 0xb7f28559
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d 76 00 58 b8 77 00 00 00 cd 80 90 8d 76
EAX: ffffffda EBX: 00000005 ECX: c0406469 EDX: bf95556c
ESI: b7e68000 EDI: c0406469 EBP: 00000005 ESP: bf9554d8
DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000296
Modules linked in: i915 x86_pkg_temp_thermal intel_powerclamp crc32_pclmul crc32c_intel intel_cstate intel_uncore intel_gtt drm_kms_helper intel_pch_thermal video button autofs4 i2c_i801 i2c_smbus fan
CR2: 00000000fe036000
It looks like kasan, xen and i915 are vulnerable.
Actual impact is "on thinkpad X60 in 5.9-rc1, screen starts blinking
after 30-or-so minutes, and machine is unusable"
[sfr@canb.auug.org.au: ARCH_PAGE_TABLE_SYNC_MASK needs vmalloc.h]
Link: https://lkml.kernel.org/r/20200825172508.16800a4f@canb.auug.org.au
[chris@chris-wilson.co.uk: changelog addition]
[pavel@ucw.cz: changelog addition]
Fixes: 2ba3e6947aed ("mm/vmalloc: track which page-table levels were modified")
Fixes: 86cf69f1d893 ("x86/mm/32: implement arch_sync_kernel_mappings()")
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk> [x86-32]
Tested-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org> [5.8+]
Link: https://lkml.kernel.org/r/20200821123746.16904-1-joro@8bytes.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
IA64 isn't really being maintained, so mark it as Odd Fixes only.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/7e719139-450f-52c2-59a2-7964a34eda1f@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Nominate Nathan and myself to be point of contact for clang/LLVM related
support, after a poll at the LLVM BoF at Linux Plumbers Conf 2020.
While corporate sponsorship is beneficial, its important to not entrust
the keys to the nukes with any one entity. Should Nathan and I find
ourselves at the same employer, I would gladly step down.
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
Acked-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lkml.kernel.org/r/20200825143540.2948637-1-ndesaulniers@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
I am leaving Marvell and already do not have access to my @marvell.com
email address. So switching over to my korg mail address or removing my
address there another maintainer is already listed. For the entries
there no other maintainer is listed I will keep looking into patches for
Cavium systems for a while until someone from Marvell takes it over.
Since I might have limited access to hardware and also limited time I
changed state to 'Odd Fixes' for those entries.
Signed-off-by: Robert Richter <rric@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ganapatrao Kulkarni <gkulkarni@marvell.com>
Cc: Sunil Goutham <sgoutham@marvell.com>
CC: Borislav Petkov <bp@alien8.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Wolfram Sang <wsa@kernel.org>,
Link: https://lkml.kernel.org/r/20200824122050.31164-1-rric@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Commit 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in
deactivate_slab()") suffered an update when picked up from LKML [1].
Specifically, relocating 'freelist = NULL' into 'freelist_corrupted()'
created a no-op statement. Fix it by sticking to the behavior intended
in the original patch [1]. In addition, make freelist_corrupted()
immune to passing NULL instead of &freelist.
The issue has been spotted via static analysis and code review.
[1] https://lore.kernel.org/linux-mm/20200331031450.12182-1-dongli.zhang@oracle.com/
Fixes: 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in deactivate_slab()")
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dongli Zhang <dongli.zhang@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200824130643.10291-1-erosca@de.adit-jv.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
We've met softlockup with "CONFIG_PREEMPT_NONE=y", when the target memcg
doesn't have any reclaimable memory.
It can be easily reproduced as below:
watchdog: BUG: soft lockup - CPU#0 stuck for 111s![memcg_test:2204]
CPU: 0 PID: 2204 Comm: memcg_test Not tainted 5.9.0-rc2+ #12
Call Trace:
shrink_lruvec+0x49f/0x640
shrink_node+0x2a6/0x6f0
do_try_to_free_pages+0xe9/0x3e0
try_to_free_mem_cgroup_pages+0xef/0x1f0
try_charge+0x2c1/0x750
mem_cgroup_charge+0xd7/0x240
__add_to_page_cache_locked+0x2fd/0x370
add_to_page_cache_lru+0x4a/0xc0
pagecache_get_page+0x10b/0x2f0
filemap_fault+0x661/0xad0
ext4_filemap_fault+0x2c/0x40
__do_fault+0x4d/0xf9
handle_mm_fault+0x1080/0x1790
It only happens on our 1-vcpu instances, because there's no chance for
oom reaper to run to reclaim the to-be-killed process.
Add a cond_resched() at the upper shrink_node_memcgs() to solve this
issue, this will mean that we will get a scheduling point for each memcg
in the reclaimed hierarchy without any dependency on the reclaimable
memory in that memcg thus making it more predictable.
Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Xunlei Pang <xlpang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: http://lkml.kernel.org/r/1598495549-67324-1-git-send-email-xlpang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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syzbot has reported an use-after-free in the uncharge_batch path
BUG: KASAN: use-after-free in instrument_atomic_write include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic64_sub_return include/asm-generic/atomic-instrumented.h:970 [inline]
BUG: KASAN: use-after-free in atomic_long_sub_return include/asm-generic/atomic-long.h:113 [inline]
BUG: KASAN: use-after-free in page_counter_cancel mm/page_counter.c:54 [inline]
BUG: KASAN: use-after-free in page_counter_uncharge+0x3d/0xc0 mm/page_counter.c:155
Write of size 8 at addr ffff8880371c0148 by task syz-executor.0/9304
CPU: 0 PID: 9304 Comm: syz-executor.0 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1f0/0x31e lib/dump_stack.c:118
print_address_description+0x66/0x620 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report+0x132/0x1d0 mm/kasan/report.c:530
check_memory_region_inline mm/kasan/generic.c:183 [inline]
check_memory_region+0x2b5/0x2f0 mm/kasan/generic.c:192
instrument_atomic_write include/linux/instrumented.h:71 [inline]
atomic64_sub_return include/asm-generic/atomic-instrumented.h:970 [inline]
atomic_long_sub_return include/asm-generic/atomic-long.h:113 [inline]
page_counter_cancel mm/page_counter.c:54 [inline]
page_counter_uncharge+0x3d/0xc0 mm/page_counter.c:155
uncharge_batch+0x6c/0x350 mm/memcontrol.c:6764
uncharge_page+0x115/0x430 mm/memcontrol.c:6796
uncharge_list mm/memcontrol.c:6835 [inline]
mem_cgroup_uncharge_list+0x70/0xe0 mm/memcontrol.c:6877
release_pages+0x13a2/0x1550 mm/swap.c:911
tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:242 [inline]
tlb_flush_mmu+0x780/0x910 mm/mmu_gather.c:249
tlb_finish_mmu+0xcb/0x200 mm/mmu_gather.c:328
exit_mmap+0x296/0x550 mm/mmap.c:3185
__mmput+0x113/0x370 kernel/fork.c:1076
exit_mm+0x4cd/0x550 kernel/exit.c:483
do_exit+0x576/0x1f20 kernel/exit.c:793
do_group_exit+0x161/0x2d0 kernel/exit.c:903
get_signal+0x139b/0x1d30 kernel/signal.c:2743
arch_do_signal+0x33/0x610 arch/x86/kernel/signal.c:811
exit_to_user_mode_loop kernel/entry/common.c:135 [inline]
exit_to_user_mode_prepare+0x8d/0x1b0 kernel/entry/common.c:166
syscall_exit_to_user_mode+0x5e/0x1a0 kernel/entry/common.c:241
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Commit 1a3e1f40962c ("mm: memcontrol: decouple reference counting from
page accounting") reworked the memcg lifetime to be bound the the struct
page rather than charges. It also removed the css_put_many from
uncharge_batch and that is causing the above splat.
uncharge_batch() is supposed to uncharge accumulated charges for all
pages freed from the same memcg. The queuing is done by uncharge_page
which however drops the memcg reference after it adds charges to the
batch. If the current page happens to be the last one holding the
reference for its memcg then the memcg is OK to go and the next page to
be freed will trigger batched uncharge which needs to access the memcg
which is gone already.
Fix the issue by taking a reference for the memcg in the current batch.
Fixes: 1a3e1f40962c ("mm: memcontrol: decouple reference counting from page accounting")
Reported-by: syzbot+b305848212deec86eabe@syzkaller.appspotmail.com
Reported-by: syzbot+b5ea6fb6f139c8b9482b@syzkaller.appspotmail.com
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Hugh Dickins <hughd@google.com>
Link: https://lkml.kernel.org/r/20200820090341.GC5033@dhcp22.suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull xfs fix from Darrick Wong:
"Fix a broken metadata verifier that would incorrectly validate attr
fork extents of a realtime file against the realtime volume"
* tag 'xfs-5.9-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: fix xfs_bmap_validate_extent_raw when checking attr fork of rt files
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When running in a dax mode, if the user maps a page with MAP_PRIVATE and
PROT_WRITE, the xfs filesystem would incorrectly update ctime and mtime
when the user hits a COW fault.
This breaks building of the Linux kernel. How to reproduce:
1. extract the Linux kernel tree on dax-mounted xfs filesystem
2. run make clean
3. run make -j12
4. run make -j12
at step 4, make would incorrectly rebuild the whole kernel (although it
was already built in step 3).
The reason for the breakage is that almost all object files depend on
objtool. When we run objtool, it takes COW page fault on its .data
section, and these faults will incorrectly update the timestamp of the
objtool binary. The updated timestamp causes make to rebuild the whole
tree.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When running in a dax mode, if the user maps a page with MAP_PRIVATE and
PROT_WRITE, the ext2 filesystem would incorrectly update ctime and mtime
when the user hits a COW fault.
This breaks building of the Linux kernel. How to reproduce:
1. extract the Linux kernel tree on dax-mounted ext2 filesystem
2. run make clean
3. run make -j12
4. run make -j12
at step 4, make would incorrectly rebuild the whole kernel (although it
was already built in step 3).
The reason for the breakage is that almost all object files depend on
objtool. When we run objtool, it takes COW page fault on its .data
section, and these faults will incorrectly update the timestamp of the
objtool binary. The updated timestamp causes make to rebuild the whole
tree.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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If we exceed UIO_FASTIOV, we don't handle the transition correctly
between an allocated vec for requests that are queued with IOSQE_ASYNC.
Store the iovec appropriately and re-set it in the iter iov in case
it changed.
Fixes: ff6165b2d7f6 ("io_uring: retain iov_iter state over io_read/io_write calls")
Reported-by: Nick Hill <nick@nickhill.org>
Tested-by: Norman Maurer <norman.maurer@googlemail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Vasily Gorbik:
- Fix GENERIC_LOCKBREAK dependency on PREEMPTION in Kconfig broken
because of a typo
- Update defconfigs
* tag 's390-5.9-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390: update defconfigs
s390: fix GENERIC_LOCKBREAK dependency typo in Kconfig
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git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Catalin Marinas:
- Fix the loading of modules built with binutils-2.35. This version
produces writable and executable .text.ftrace_trampoline section
which is rejected by the kernel.
- Remove the exporting of cpu_logical_map() as the Tegra driver has now
been fixed and no longer uses this function.
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64/module: set trampoline section flags regardless of CONFIG_DYNAMIC_FTRACE
arm64: Remove exporting cpu_logical_map symbol
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git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux
Pull MIPS fixes from Thomas Bogendoerfer:
"A few MIPS fixes:
- fallthrough fallout fix
- BMIPS fixes
- MSA fix to avoid leaking MSA register contents
- Loongson perf and cpu feature fix
- SNI interrupt fix"
* tag 'mips_fixes_5.9_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
MIPS: SNI: Fix SCSI interrupt
MIPS: add missing MSACSR and upper MSA initialization
MIPS: perf: Fix wrong check condition of Loongson event IDs
mips/oprofile: Fix fallthrough placement
MIPS: Loongson64: Remove unnecessary inclusion of boot_param.h
MIPS: BMIPS: Also call bmips_cpu_setup() for secondary cores
MIPS: mm: BMIPS5000 has inclusive physical caches
MIPS: Loongson64: Do not override watch and ejtag feature
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