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2024-07-14Merge branch 'for-6.10-fixes' into for-6.11Tejun Heo
2024-07-12cgroup/misc: Introduce misc.events.localXiu Jianfeng
Currently the event counting provided by misc.events is hierarchical, it's not practical if user is only concerned with events of a specified cgroup. Therefore, introduce misc.events.local collect events specific to the given cgroup. This is analogous to memory.events.local and pids.events.local. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-07-05cgroup/rstat: add force idle show helperChen Ridong
In the function cgroup_base_stat_cputime_show, there are five instances of #ifdef, which makes the code not concise. To address this, add the function cgroup_force_idle_show to make the code more succinct. Signed-off-by: Chen Ridong <chenridong@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-07-03cgroup: Protect css->cgroup write under css_set_lockWaiman Long
The writing of css->cgroup associated with the cgroup root in rebind_subsystems() is currently protected only by cgroup_mutex. However, the reading of css->cgroup in both proc_cpuset_show() and proc_cgroup_show() is protected just by css_set_lock. That makes the readers susceptible to racing problems like data tearing or caching. It is also a problem that can be reported by KCSAN. This can be fixed by using READ_ONCE() and WRITE_ONCE() to access css->cgroup. Alternatively, the writing of css->cgroup can be moved under css_set_lock as well which is done by this patch. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-07-03cgroup/misc: Introduce misc.peakXiu Jianfeng
Introduce misc.peak to record the historical maximum usage of the resource, as in some scenarios the value of misc.max could be adjusted based on the peak usage of the resource. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-06-28cgroup/cpuset: Prevent UAF in proc_cpuset_show()Chen Ridong
An UAF can happen when /proc/cpuset is read as reported in [1]. This can be reproduced by the following methods: 1.add an mdelay(1000) before acquiring the cgroup_lock In the cgroup_path_ns function. 2.$cat /proc/<pid>/cpuset repeatly. 3.$mount -t cgroup -o cpuset cpuset /sys/fs/cgroup/cpuset/ $umount /sys/fs/cgroup/cpuset/ repeatly. The race that cause this bug can be shown as below: (umount) | (cat /proc/<pid>/cpuset) css_release | proc_cpuset_show css_release_work_fn | css = task_get_css(tsk, cpuset_cgrp_id); css_free_rwork_fn | cgroup_path_ns(css->cgroup, ...); cgroup_destroy_root | mutex_lock(&cgroup_mutex); rebind_subsystems | cgroup_free_root | | // cgrp was freed, UAF | cgroup_path_ns_locked(cgrp,..); When the cpuset is initialized, the root node top_cpuset.css.cgrp will point to &cgrp_dfl_root.cgrp. In cgroup v1, the mount operation will allocate cgroup_root, and top_cpuset.css.cgrp will point to the allocated &cgroup_root.cgrp. When the umount operation is executed, top_cpuset.css.cgrp will be rebound to &cgrp_dfl_root.cgrp. The problem is that when rebinding to cgrp_dfl_root, there are cases where the cgroup_root allocated by setting up the root for cgroup v1 is cached. This could lead to a Use-After-Free (UAF) if it is subsequently freed. The descendant cgroups of cgroup v1 can only be freed after the css is released. However, the css of the root will never be released, yet the cgroup_root should be freed when it is unmounted. This means that obtaining a reference to the css of the root does not guarantee that css.cgrp->root will not be freed. Fix this problem by using rcu_read_lock in proc_cpuset_show(). As cgroup_root is kfree_rcu after commit d23b5c577715 ("cgroup: Make operations on the cgroup root_list RCU safe"), css->cgroup won't be freed during the critical section. To call cgroup_path_ns_locked, css_set_lock is needed, so it is safe to replace task_get_css with task_css. [1] https://syzkaller.appspot.com/bug?extid=9b1ff7be974a403aa4cd Fixes: a79a908fd2b0 ("cgroup: introduce cgroup namespaces") Signed-off-by: Chen Ridong <chenridong@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-06-19cgroup/cpuset: Make cpuset.cpus.exclusive independent of cpuset.cpusWaiman Long
The "cpuset.cpus.exclusive.effective" value is currently limited to a subset of its "cpuset.cpus". This makes the exclusive CPUs distribution hierarchy subsumed within the larger "cpuset.cpus" hierarchy. We have to decide on what CPUs are used locally and what CPUs can be passed down as exclusive CPUs down the hierarchy and combine them into "cpuset.cpus". The advantage of the current scheme is to have only one hierarchy to worry about. However, it make it harder to use as all the "cpuset.cpus" values have to be properly set along the way down to the designated remote partition root. It also makes it more cumbersome to find out what CPUs can be used locally. Make creation of remote partition simpler by breaking the dependency of "cpuset.cpus.exclusive" on "cpuset.cpus" and make them independent entities. Now we have two separate hierarchies - one for setting "cpuset.cpus.effective" and the other one for setting "cpuset.cpus.exclusive.effective". We may not need to set "cpuset.cpus" when we activate a partition root anymore. Also update Documentation/admin-guide/cgroup-v2.rst and cpuset.c comment to document this change. Suggested-by: Petr Malat <oss@malat.biz> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-06-19cgroup/cpuset: Delay setting of CS_CPU_EXCLUSIVE until valid partitionWaiman Long
The CS_CPU_EXCLUSIVE flag is currently set whenever cpuset.cpus.exclusive is set to make sure that the exclusivity test will be run to ensure its exclusiveness. At the same time, this flag can be changed whenever the partition root state is changed. For example, the CS_CPU_EXCLUSIVE flag will be reset whenever a partition root becomes invalid. This makes using CS_CPU_EXCLUSIVE to ensure exclusiveness a bit fragile. The current scheme also makes setting up a cpuset.cpus.exclusive hierarchy to enable remote partition harder as cpuset.cpus.exclusive cannot overlap with any cpuset.cpus of sibling cpusets if their cpuset.cpus.exclusive aren't set. Solve these issues by deferring the setting of CS_CPU_EXCLUSIVE flag until the cpuset become a valid partition root while adding new checks in validate_change() to ensure that cpuset.cpus.exclusive of sibling cpusets cannot overlap. An additional check is also added to validate_change() to make sure that cpuset.cpus of one cpuset cannot be a subset of cpuset.cpus.exclusive of a sibling cpuset to avoid the problem that none of those CPUs will be available when these exclusive CPUs are extracted out to a newly enabled partition root. The Documentation/admin-guide/cgroup-v2.rst file is updated to document the new constraints. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-06-19cgroup/cpuset: Fix remote root partition creation problemWaiman Long
Since commit 181c8e091aae ("cgroup/cpuset: Introduce remote partition"), a remote partition can be created underneath a non-partition root cpuset as long as its exclusive_cpus are set to distribute exclusive CPUs down to its children. The generate_sched_domains() function, however, doesn't take into account this new behavior and hence will fail to create the sched domain needed for a remote root (non-isolated) partition. There are two issues related to remote partition support. First of all, generate_sched_domains() has a fast path that is activated if root_load_balance is true and top_cpuset.nr_subparts is non-zero. The later condition isn't quite correct for remote partitions as nr_subparts just shows the number of local child partitions underneath it. There can be no local child partition under top_cpuset even if there are remote partitions further down the hierarchy. Fix that by checking for subpartitions_cpus which contains exclusive CPUs allocated to both local and remote partitions. Secondly, the valid partition check for subtree skipping in the csa[] generation loop isn't enough as remote partition does not need to have a partition root parent. Fix this problem by breaking csa[] array generation loop of generate_sched_domains() into v1 and v2 specific parts and checking a cpuset's exclusive_cpus before skipping its subtree in the v2 case. Also simplify generate_sched_domains() for cgroup v2 as only non-isolating partition roots should be included in building the cpuset array and none of the v1 scheduling attributes other than a different way to create an isolated partition are supported. Fixes: 181c8e091aae ("cgroup/cpuset: Introduce remote partition") Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-06-19cgroup: avoid the unnecessary list_add(dying_tasks) in cgroup_exit()Oleg Nesterov
cgroup_exit() needs to do this only if the exiting task is a leader and it is not the last live thread. The patch doesn't use delay_group_leader(), atomic_read(signal->live) matches the code css_task_iter_advance() more. cgroup_release() can now check list_empty(task->cg_list) before it takes css_set_lock and calls ss_set_skip_task_iters(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-06-03cgroup/cpuset: Optimize isolated partition only generate_sched_domains() callsWaiman Long
If only isolated partitions are being created underneath the cgroup root, there will only be one sched domain with top_cpuset.effective_cpus. We can skip the unnecessary sched domains scanning code and save some cycles. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-06-01cgroup/cpuset: Reduce the lock protecting CS_SCHED_LOAD_BALANCEXiu Jianfeng
In the cpuset_css_online(), clearing the CS_SCHED_LOAD_BALANCE bit of cs->flags is guarded by callback_lock and cpuset_mutex. There is no problem with itself, because it is consistent with the description of there two global lock at the beginning of this file. However, since the operation of checking, setting and clearing the flag bit is atomic, protection of callback_lock is unnecessary here, see CS_SPREAD_*. so to make it more consistent with the other code, move the operation outside the critical section of callback_lock. No functional changes intended. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-05-26kernel/cgroup: cleanup cgroup_base_files when fail to add cgroup_psi_filesDavid Wang
Even though css_clear_dir would be called to cleanup all existing cgroup files when css_populate_dir failed, reclaiming newly created cgroup files before css_populate_dir returns with failure makes code more consistent. Signed-off-by: David Wang <00107082@163.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-05-26cgroup/pids: Add pids.events.localMichal Koutný
Hierarchical counting of events is not practical for watching when a particular pids.max is being hit. Therefore introduce .local flavor of events file (akin to memory controller) that collects only events relevant to given cgroup. The file is only added to the default hierarchy. Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-05-26cgroup/pids: Make event counters hierarchicalMichal Koutný
The pids.events file should honor the hierarchy, so make the events propagate from their origin up to the root on the unified hierarchy. The legacy behavior remains non-hierarchical. Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-05-26cgroup/pids: Separate semantics of pids.events related to pids.maxMichal Koutný
Currently, when pids.max limit is breached in the hierarchy, the event is counted and reported in the cgroup where the forking task resides. This decouples the limit and the notification caused by the limit making it hard to detect when the actual limit was effected. Redefine the pids.events:max as: the number of times the limit of the cgroup was hit. (Implementation differentiates also "forkfail" event but this is currently not exposed as it would better fit into pids.stat. It also differs from pids.events:max only when pids.max is configured on non-leaf cgroups.) Since it changes semantics of the original "max" event, introduce this change only in the v2 API of the controller and add a cgroup2 mount option to revert to the legacy behavior. Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-05-26cgroup/cpuset: Update comment on callback_lockXiu Jianfeng
Since commit 51ffe41178c4 ("cpuset: convert away from cftype->read()"), cpuset_common_file_read() has been renamed. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-05-26cgroup/cpuset: Remove unnecessary zeroingXiu Jianfeng
The struct cpuset is kzalloc'd, all the members are zeroed already, so don't need nodes_clear() here. No functional changes intended. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-05-19Merge tag 'sched-urgent-2024-05-18' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: - Fix a sched_balance_newidle setting bug - Fix bug in the setting of /sys/fs/cgroup/test/cpu.max.burst - Fix variable-shadowing build warning - Extend sched-domains debug output - Fix documentation - Fix comments * tag 'sched-urgent-2024-05-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/core: Fix incorrect initialization of the 'burst' parameter in cpu_max_write() sched/fair: Remove stale FREQUENCY_UTIL comment sched/fair: Fix initial util_avg calculation docs: cgroup-v1: Clarify that domain levels are system-specific sched/debug: Dump domains' level sched/fair: Allow disabling sched_balance_newidle with sched_relax_domain_level arch/topology: Fix variable naming to avoid shadowing
2024-05-17sched/fair: Allow disabling sched_balance_newidle with sched_relax_domain_levelVitalii Bursov
Change relax_domain_level checks so that it would be possible to include or exclude all domains from newidle balancing. This matches the behavior described in the documentation: -1 no request. use system default or follow request of others. 0 no search. 1 search siblings (hyperthreads in a core). "2" enables levels 0 and 1, level_max excludes the last (level_max) level, and level_max+1 includes all levels. Fixes: 1d3504fcf560 ("sched, cpuset: customize sched domains, core") Signed-off-by: Vitalii Bursov <vitaly@bursov.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Reviewed-by: Valentin Schneider <vschneid@redhat.com> Link: https://lore.kernel.org/r/bd6de28e80073c79466ec6401cdeae78f0d4423d.1714488502.git.vitaly@bursov.com
2024-05-14cgroup/rstat: add cgroup_rstat_cpu_lock helpers and tracepointsJesper Dangaard Brouer
This closely resembles helpers added for the global cgroup_rstat_lock in commit fc29e04ae1ad ("cgroup/rstat: add cgroup_rstat_lock helpers and tracepoints"). This is for the per CPU lock cgroup_rstat_cpu_lock. Based on production workloads, we observe the fast-path "update" function cgroup_rstat_updated() is invoked around 3 million times per sec, while the "flush" function cgroup_rstat_flush_locked(), walking each possible CPU, can see periodic spikes of 700 invocations/sec. For this reason, the tracepoints are split into normal and fastpath versions for this per-CPU lock. Making it feasible for production to continuously monitor the non-fastpath tracepoint to detect lock contention issues. The reason for monitoring is that lock disables IRQs which can disturb e.g. softirq processing on the local CPUs involved. When the global cgroup_rstat_lock stops disabling IRQs (e.g converted to a mutex), this per CPU lock becomes the next bottleneck that can introduce latency variations. A practical bpftrace script for monitoring contention latency: bpftrace -e ' tracepoint:cgroup:cgroup_rstat_cpu_lock_contended { @start[tid]=nsecs; @cnt[probe]=count()} tracepoint:cgroup:cgroup_rstat_cpu_locked { if (args->contended) { @wait_ns=hist(nsecs-@start[tid]); delete(@start[tid]);} @cnt[probe]=count()} interval:s:1 {time("%H:%M:%S "); print(@wait_ns); print(@cnt); clear(@cnt);}' Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-04-25cgroup/cpuset: Remove outdated comment in sched_partition_write()Xiu Jianfeng
The comment here is outdated and can cause confusion, from the code perspective, there’s also no need for new comment, so just remove it. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-04-23cgroup/cpuset: Fix incorrect top_cpuset flagsWaiman Long
Commit 8996f93fc388 ("cgroup/cpuset: Statically initialize more members of top_cpuset") uses an incorrect "<" relational operator for the CS_SCHED_LOAD_BALANCE bit when initializing the top_cpuset. This results in load_balancing turned off by default in the top cpuset which is bad for performance. Fix this by using the BIT() helper macro to set the desired top_cpuset flags and avoid similar mistake from being made in the future. Fixes: 8996f93fc388 ("cgroup/cpuset: Statically initialize more members of top_cpuset") Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-04-23cgroup/cpuset: Avoid clearing CS_SCHED_LOAD_BALANCE twiceXiu Jianfeng
In cpuset_css_online(), CS_SCHED_LOAD_BALANCE will be cleared twice, the former one in the is_in_v2_mode() case could be removed because is_in_v2_mode() can be true for cgroup v1 if the "cpuset_v2_mode" mount option is specified, that balance flag change isn't appropriate for this particular case. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-04-22cgroup/cpuset: Statically initialize more members of top_cpusetXiu Jianfeng
Initializing top_cpuset.relax_domain_level and setting CS_SCHED_LOAD_BALANCE to top_cpuset.flags in cpuset_init() could be completed at the time of top_cpuset definition by compiler. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Reviewed-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-04-19cgroup: Avoid unnecessary looping in cgroup_no_v1()Xiu Jianfeng
No need to continue the for_each_subsys loop after the token matches the name of subsys and cgroup_no_v1_mask is set. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-04-18cgroup, legacy_freezer: update comment for freezer_css_offline()Xiu Jianfeng
After commit f5d39b020809 ("freezer,sched: Rewrite core freezer logic"), system_freezing_count was replaced by freezer_active. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-04-18cgroup: don't call cgroup1_pidlist_destroy_all() for v2Xiu Jianfeng
Currently cgroup1_pidlist_destroy_all() will be called when releasing cgroup even if the cgroup is on default hierarchy, however it doesn't make any sense for v2 to destroy pidlist of v1. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-04-17cgroup_freezer: update comment for freezer_css_online()Xiu Jianfeng
The freezer->lock was replaced by freezer_mutex in commit e5ced8ebb10c ("cgroup_freezer: replace freezer->lock with freezer_mutex"), so the comment here is out-of-date, update it. Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-04-17cgroup/rstat: desc member cgrp in cgroup_rstat_flush_releaseJesper Dangaard Brouer
Recent change to cgroup_rstat_flush_release added a parameter cgrp, which is used by tracepoint to correlate with other tracepoints that also have this cgrp. The kernel test robot detected kernel doc was missing a description of this member. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202404170821.HwZGISTY-lkp@intel.com/ Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-04-16cgroup/rstat: add cgroup_rstat_lock helpers and tracepointsJesper Dangaard Brouer
This commit enhances the ability to troubleshoot the global cgroup_rstat_lock by introducing wrapper helper functions for the lock along with associated tracepoints. Although global, the cgroup_rstat_lock helper APIs and tracepoints take arguments such as cgroup pointer and cpu_in_loop variable. This adjustment is made because flushing occurs per cgroup despite the lock being global. Hence, when troubleshooting, it's important to identify the relevant cgroup. The cpu_in_loop variable is necessary because the global lock may be released within the main flushing loop that traverses CPUs. In the tracepoints, the cpu_in_loop value is set to -1 when acquiring the main lock; otherwise, it denotes the CPU number processed last. The new feature in this patchset is detecting when lock is contended. The tracepoints are implemented with production in mind. For minimum overhead attach to cgroup:cgroup_rstat_lock_contended, which only gets activated when trylock detects lock is contended. A quick production check for issues could be done via this perf commands: perf record -g -e cgroup:cgroup_rstat_lock_contended Next natural question would be asking how long time do lock contenders wait for obtaining the lock. This can be answered by measuring the time between cgroup:cgroup_rstat_lock_contended and cgroup:cgroup_rstat_locked when args->contended is set. Like this bpftrace script: bpftrace -e ' tracepoint:cgroup:cgroup_rstat_lock_contended {@start[tid]=nsecs} tracepoint:cgroup:cgroup_rstat_locked { if (args->contended) { @wait_ns=hist(nsecs-@start[tid]); delete(@start[tid]);}} interval:s:1 {time("%H:%M:%S "); print(@wait_ns); }' Extending with time spend holding the lock will be more expensive as this also looks at all the non-contended cases. Like this bpftrace script: bpftrace -e ' tracepoint:cgroup:cgroup_rstat_lock_contended {@start[tid]=nsecs} tracepoint:cgroup:cgroup_rstat_locked { @locked[tid]=nsecs; if (args->contended) { @wait_ns=hist(nsecs-@start[tid]); delete(@start[tid]);}} tracepoint:cgroup:cgroup_rstat_unlock { @locked_ns=hist(nsecs-@locked[tid]); delete(@locked[tid]);} interval:s:1 {time("%H:%M:%S "); print(@wait_ns);print(@locked_ns); }' Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-04-16cgroup/pids: Remove superfluous zeroingMichal Koutný
Atomic counters are in kzalloc'd struct. They are zeroed already and atomic64_t does not need special initialization (cf kernel/trace/trace_clock.c:trace_counter). Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-04-08cgroup/cpuset: Make cpuset hotplug processing synchronousWaiman Long
Since commit 3a5a6d0c2b03("cpuset: don't nest cgroup_mutex inside get_online_cpus()"), cpuset hotplug was done asynchronously via a work function. This is to avoid recursive locking of cgroup_mutex. Since then, the cgroup locking scheme has changed quite a bit. A cpuset_mutex was introduced to protect cpuset specific operations. The cpuset_mutex is then replaced by a cpuset_rwsem. With commit d74b27d63a8b ("cgroup/cpuset: Change cpuset_rwsem and hotplug lock order"), cpu_hotplug_lock is acquired before cpuset_rwsem. Later on, cpuset_rwsem is reverted back to cpuset_mutex. All these locking changes allow the hotplug code to call into cpuset core directly. The following commits were also merged due to the asynchronous nature of cpuset hotplug processing. - commit b22afcdf04c9 ("cpu/hotplug: Cure the cpusets trainwreck") - commit 50e76632339d ("sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs") - commit 28b89b9e6f7b ("cpuset: handle race between CPU hotplug and cpuset_hotplug_work") Clean up all these bandages by making cpuset hotplug processing synchronous again with the exception that the call to cgroup_transfer_tasks() to transfer tasks out of an empty cgroup v1 cpuset, if necessary, will still be done via a work function due to the existing cgroup_mutex -> cpu_hotplug_lock dependency. It is possible to reverse that dependency, but that will require updating a number of different cgroup controllers. This special hotplug code path should be rarely taken anyway. As all the cpuset states will be updated by the end of the hotplug operation, we can revert most the above commits except commit 50e76632339d ("sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs") which is partially reverted. Also removing some cpus_read_lock trylock attempts in the cpuset partition code as they are no longer necessary since the cpu_hotplug_lock is now held for the whole duration of the cpuset hotplug code path. Signed-off-by: Waiman Long <longman@redhat.com> Tested-by: Valentin Schneider <vschneid@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-03-12Merge tag 'net-next-6.9' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Jakub Kicinski: "Core & protocols: - Large effort by Eric to lower rtnl_lock pressure and remove locks: - Make commonly used parts of rtnetlink (address, route dumps etc) lockless, protected by RCU instead of rtnl_lock. - Add a netns exit callback which already holds rtnl_lock, allowing netns exit to take rtnl_lock once in the core instead of once for each driver / callback. - Remove locks / serialization in the socket diag interface. - Remove 6 calls to synchronize_rcu() while holding rtnl_lock. - Remove the dev_base_lock, depend on RCU where necessary. - Support busy polling on a per-epoll context basis. Poll length and budget parameters can be set independently of system defaults. - Introduce struct net_hotdata, to make sure read-mostly global config variables fit in as few cache lines as possible. - Add optional per-nexthop statistics to ease monitoring / debug of ECMP imbalance problems. - Support TCP_NOTSENT_LOWAT in MPTCP. - Ensure that IPv6 temporary addresses' preferred lifetimes are long enough, compared to other configured lifetimes, and at least 2 sec. - Support forwarding of ICMP Error messages in IPSec, per RFC 4301. - Add support for the independent control state machine for bonding per IEEE 802.1AX-2008 5.4.15 in addition to the existing coupled control state machine. - Add "network ID" to MCTP socket APIs to support hosts with multiple disjoint MCTP networks. - Re-use the mono_delivery_time skbuff bit for packets which user space wants to be sent at a specified time. Maintain the timing information while traversing veth links, bridge etc. - Take advantage of MSG_SPLICE_PAGES for RxRPC DATA and ACK packets. - Simplify many places iterating over netdevs by using an xarray instead of a hash table walk (hash table remains in place, for use on fastpaths). - Speed up scanning for expired routes by keeping a dedicated list. - Speed up "generic" XDP by trying harder to avoid large allocations. - Support attaching arbitrary metadata to netconsole messages. Things we sprinkled into general kernel code: - Enforce VM_IOREMAP flag and range in ioremap_page_range and introduce VM_SPARSE kind and vm_area_[un]map_pages (used by bpf_arena). - Rework selftest harness to enable the use of the full range of ksft exit code (pass, fail, skip, xfail, xpass). Netfilter: - Allow userspace to define a table that is exclusively owned by a daemon (via netlink socket aliveness) without auto-removing this table when the userspace program exits. Such table gets marked as orphaned and a restarting management daemon can re-attach/regain ownership. - Speed up element insertions to nftables' concatenated-ranges set type. Compact a few related data structures. BPF: - Add BPF token support for delegating a subset of BPF subsystem functionality from privileged system-wide daemons such as systemd through special mount options for userns-bound BPF fs to a trusted & unprivileged application. - Introduce bpf_arena which is sparse shared memory region between BPF program and user space where structures inside the arena can have pointers to other areas of the arena, and pointers work seamlessly for both user-space programs and BPF programs. - Introduce may_goto instruction that is a contract between the verifier and the program. The verifier allows the program to loop assuming it's behaving well, but reserves the right to terminate it. - Extend the BPF verifier to enable static subprog calls in spin lock critical sections. - Support registration of struct_ops types from modules which helps projects like fuse-bpf that seeks to implement a new struct_ops type. - Add support for retrieval of cookies for perf/kprobe multi links. - Support arbitrary TCP SYN cookie generation / validation in the TC layer with BPF to allow creating SYN flood handling in BPF firewalls. - Add code generation to inline the bpf_kptr_xchg() helper which improves performance when stashing/popping the allocated BPF objects. Wireless: - Add SPP (signaling and payload protected) AMSDU support. - Support wider bandwidth OFDMA, as required for EHT operation. Driver API: - Major overhaul of the Energy Efficient Ethernet internals to support new link modes (2.5GE, 5GE), share more code between drivers (especially those using phylib), and encourage more uniform behavior. Convert and clean up drivers. - Define an API for querying per netdev queue statistics from drivers. - IPSec: account in global stats for fully offloaded sessions. - Create a concept of Ethernet PHY Packages at the Device Tree level, to allow parameterizing the existing PHY package code. - Enable Rx hashing (RSS) on GTP protocol fields. Misc: - Improvements and refactoring all over networking selftests. - Create uniform module aliases for TC classifiers, actions, and packet schedulers to simplify creating modprobe policies. - Address all missing MODULE_DESCRIPTION() warnings in networking. - Extend the Netlink descriptions in YAML to cover message encapsulation or "Netlink polymorphism", where interpretation of nested attributes depends on link type, classifier type or some other "class type". Drivers: - Ethernet high-speed NICs: - Add a new driver for Marvell's Octeon PCI Endpoint NIC VF. - Intel (100G, ice, idpf): - support E825-C devices - nVidia/Mellanox: - support devices with one port and multiple PCIe links - Broadcom (bnxt): - support n-tuple filters - support configuring the RSS key - Wangxun (ngbe/txgbe): - implement irq_domain for TXGBE's sub-interrupts - Pensando/AMD: - support XDP - optimize queue submission and wakeup handling (+17% bps) - optimize struct layout, saving 28% of memory on queues - Ethernet NICs embedded and virtual: - Google cloud vNIC: - refactor driver to perform memory allocations for new queue config before stopping and freeing the old queue memory - Synopsys (stmmac): - obey queueMaxSDU and implement counters required by 802.1Qbv - Renesas (ravb): - support packet checksum offload - suspend to RAM and runtime PM support - Ethernet switches: - nVidia/Mellanox: - support for nexthop group statistics - Microchip: - ksz8: implement PHY loopback - add support for KSZ8567, a 7-port 10/100Mbps switch - PTP: - New driver for RENESAS FemtoClock3 Wireless clock generator. - Support OCP PTP cards designed and built by Adva. - CAN: - Support recvmsg() flags for own, local and remote traffic on CAN BCM sockets. - Support for esd GmbH PCIe/402 CAN device family. - m_can: - Rx/Tx submission coalescing - wake on frame Rx - WiFi: - Intel (iwlwifi): - enable signaling and payload protected A-MSDUs - support wider-bandwidth OFDMA - support for new devices - bump FW API to 89 for AX devices; 90 for BZ/SC devices - MediaTek (mt76): - mt7915: newer ADIE version support - mt7925: radio temperature sensor support - Qualcomm (ath11k): - support 6 GHz station power modes: Low Power Indoor (LPI), Standard Power) SP and Very Low Power (VLP) - QCA6390 & WCN6855: support 2 concurrent station interfaces - QCA2066 support - Qualcomm (ath12k): - refactoring in preparation for Multi-Link Operation (MLO) support - 1024 Block Ack window size support - firmware-2.bin support - support having multiple identical PCI devices (firmware needs to have ATH12K_FW_FEATURE_MULTI_QRTR_ID) - QCN9274: support split-PHY devices - WCN7850: enable Power Save Mode in station mode - WCN7850: P2P support - RealTek: - rtw88: support for more rtw8811cu and rtw8821cu devices - rtw89: support SCAN_RANDOM_SN and SET_SCAN_DWELL - rtlwifi: speed up USB firmware initialization - rtwl8xxxu: - RTL8188F: concurrent interface support - Channel Switch Announcement (CSA) support in AP mode - Broadcom (brcmfmac): - per-vendor feature support - per-vendor SAE password setup - DMI nvram filename quirk for ACEPC W5 Pro" * tag 'net-next-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2255 commits) nexthop: Fix splat with CONFIG_DEBUG_PREEMPT=y nexthop: Fix out-of-bounds access during attribute validation nexthop: Only parse NHA_OP_FLAGS for dump messages that require it nexthop: Only parse NHA_OP_FLAGS for get messages that require it bpf: move sleepable flag from bpf_prog_aux to bpf_prog bpf: hardcode BPF_PROG_PACK_SIZE to 2MB * num_possible_nodes() selftests/bpf: Add kprobe multi triggering benchmarks ptp: Move from simple ida to xarray vxlan: Remove generic .ndo_get_stats64 vxlan: Do not alloc tstats manually devlink: Add comments to use netlink gen tool nfp: flower: handle acti_netdevs allocation failure net/packet: Add getsockopt support for PACKET_COPY_THRESH net/netlink: Add getsockopt support for NETLINK_LISTEN_ALL_NSID selftests/bpf: Add bpf_arena_htab test. selftests/bpf: Add bpf_arena_list test. selftests/bpf: Add unit tests for bpf_arena_alloc/free_pages bpf: Add helper macro bpf_addr_space_cast() libbpf: Recognize __arena global variables. bpftool: Recognize arena map type ...
2024-03-11Merge tag 'cgroup-for-6.9' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "A quiet cycle. One trivial doc update patch. Two patches to drop the now defunct memory_spread_slab feature from cgroup1 cpuset" * tag 'cgroup-for-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup/cpuset: Mark memory_spread_slab as obsolete cgroup/cpuset: Remove cpuset_do_slab_mem_spread() docs: cgroup-v1: add missing code-block tags
2024-03-07Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR. No conflicts. Adjacent changes: net/core/page_pool_user.c 0b11b1c5c320 ("netdev: let netlink core handle -EMSGSIZE errors") 429679dcf7d9 ("page_pool: fix netlink dump stop/resume") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-02-29cgroup/cpuset: Fix retval in update_cpumask()Kamalesh Babulal
The update_cpumask(), checks for newly requested cpumask by calling validate_change(), which returns an error on passing an invalid set of cpu(s). Independent of the error returned, update_cpumask() always returns zero, suppressing the error and returning success to the user on writing an invalid cpu range for a cpuset. Fix it by returning retval instead, which is returned by validate_change(). Fixes: 99fe36ba6fc1 ("cgroup/cpuset: Improve temporary cpumasks handling") Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com> Reviewed-by: Waiman Long <longman@redhat.com> Cc: stable@vger.kernel.org # v6.6+ Signed-off-by: Tejun Heo <tj@kernel.org>
2024-02-29cgroup/cpuset: Mark memory_spread_slab as obsoleteXiongwei Song
We've removed the SLAB allocator, cpuset_do_slab_mem_spread() and SLAB_MEM_SPREAD, memory_spread_slab is a no-op now. We can mark memory_spread_slab as obsolete in case someone still wants to use it after cpuset_do_slab_mem_spread() removed. For more details, please check [1]. [1] https://lore.kernel.org/lkml/32bc1403-49da-445a-8c00-9686a3b0d6a3@redhat.com/T/#m8e292e21b00f95a4bb8086371fa7387fa4ea8f60 tj: Description and cosmetic updates. Signed-off-by: Xiongwei Song <xiongwei.song@windriver.com> Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2024-02-28cgroup/cpuset: Fix a memory leak in update_exclusive_cpumask()Waiman Long
Fix a possible memory leak in update_exclusive_cpumask() by moving the alloc_cpumasks() down after the validate_change() check which can fail and still before the temporary cpumasks are needed. Fixes: e2ffe502ba45 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2") Reported-and-tested-by: Mirsad Todorovac <mirsad.todorovac@alu.hr> Closes: https://lore.kernel.org/lkml/14915689-27a3-4cd8-80d2-9c30d0c768b6@alu.unizg.hr Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org # v6.7+
2024-01-31bpf: treewide: Annotate BPF kfuncs in BTFDaniel Xu
This commit marks kfuncs as such inside the .BTF_ids section. The upshot of these annotations is that we'll be able to automatically generate kfunc prototypes for downstream users. The process is as follows: 1. In source, use BTF_KFUNCS_START/END macro pair to mark kfuncs 2. During build, pahole injects into BTF a "bpf_kfunc" BTF_DECL_TAG for each function inside BTF_KFUNCS sets 3. At runtime, vmlinux or module BTF is made available in sysfs 4. At runtime, bpftool (or similar) can look at provided BTF and generate appropriate prototypes for functions with "bpf_kfunc" tag To ensure future kfunc are similarly tagged, we now also return error inside kfunc registration for untagged kfuncs. For vmlinux kfuncs, we also WARN(), as initcall machinery does not handle errors. Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Acked-by: Benjamin Tissoires <bentiss@kernel.org> Link: https://lore.kernel.org/r/e55150ceecbf0a5d961e608941165c0bee7bc943.1706491398.git.dxu@dxuuu.xyz Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-01-18Merge tag 'driver-core-6.8-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here are the set of driver core and kernfs changes for 6.8-rc1. Nothing major in here this release cycle, just lots of small cleanups and some tweaks on kernfs that in the very end, got reverted and will come back in a safer way next release cycle. Included in here are: - more driver core 'const' cleanups and fixes - fw_devlink=rpm is now the default behavior - kernfs tiny changes to remove some string functions - cpu handling in the driver core is updated to work better on many systems that add topologies and cpus after booting - other minor changes and cleanups All of the cpu handling patches have been acked by the respective maintainers and are coming in here in one series. Everything has been in linux-next for a while with no reported issues" * tag 'driver-core-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (51 commits) Revert "kernfs: convert kernfs_idr_lock to an irq safe raw spinlock" kernfs: convert kernfs_idr_lock to an irq safe raw spinlock class: fix use-after-free in class_register() PM: clk: make pm_clk_add_notifier() take a const pointer EDAC: constantify the struct bus_type usage kernfs: fix reference to renamed function driver core: device.h: fix Excess kernel-doc description warning driver core: class: fix Excess kernel-doc description warning driver core: mark remaining local bus_type variables as const driver core: container: make container_subsys const driver core: bus: constantify subsys_register() calls driver core: bus: make bus_sort_breadthfirst() take a const pointer kernfs: d_obtain_alias(NULL) will do the right thing... driver core: Better advertise dev_err_probe() kernfs: Convert kernfs_path_from_node_locked() from strlcpy() to strscpy() kernfs: Convert kernfs_name_locked() from strlcpy() to strscpy() kernfs: Convert kernfs_walk_ns() from strlcpy() to strscpy() initramfs: Expose retained initrd as sysfs file fs/kernfs/dir: obey S_ISGID kernel/cgroup: use kernfs_create_dir_ns() ...
2024-01-08Merge tag 'cgroup-for-6.8' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: - Yafang Shao added task_get_cgroup1() helper to enable a similar BPF helper so that BPF progs can be more useful on cgroup1 hierarchies. While cgroup1 is mostly in maintenance mode, this addition is very small while having an outsized usefulness for users who are still on cgroup1. Yafang also optimized root cgroup list access by making it RCU protected in the process. - Waiman Long optimized rstat operation leading to substantially lower and more consistent lock hold time while flushing the hierarchical statistics. As the lock can be acquired briefly in various hot paths, this reduction has cascading benefits. - Waiman also improved the quality of isolation for cpuset's isolated partitions. CPUs which are allocated to isolated partitions are now excluded from running unbound work items and cpu_is_isolated() test which is used by vmstat and memcg to reduce interference now includes cpuset isolated CPUs. While it isn't there yet, the hope is eventually reaching parity with the isolation level provided by the `isolcpus` boot param but in a dynamic manner. * tag 'cgroup-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Move rcu_head up near the top of cgroup_root cgroup/cpuset: Include isolated cpuset CPUs in cpu_is_isolated() check cgroup: Avoid false cacheline sharing of read mostly rstat_cpu cgroup/rstat: Optimize cgroup_rstat_updated_list() cgroup: Fix documentation for cpu.idle cgroup/cpuset: Expose cpuset.cpus.isolated workqueue: Move workqueue_set_unbound_cpumask() and its helpers inside CONFIG_SYSFS cgroup/rstat: Reduce cpu_lock hold time in cgroup_rstat_flush_locked() cgroup/cpuset: Take isolated CPUs out of workqueue unbound cpumask cgroup/cpuset: Keep track of CPUs in isolated partitions selftests/cgroup: Minor code cleanup and reorganization of test_cpuset_prs.sh workqueue: Add workqueue_unbound_exclude_cpumask() to exclude CPUs from wq_unbound_cpumask selftests: cgroup: Fixes a typo in a comment cgroup: Add a new helper for cgroup1 hierarchy cgroup: Add annotation for holding namespace_sem in current_cgns_cgroup_from_root() cgroup: Eliminate the need for cgroup_mutex in proc_cgroup_show() cgroup: Make operations on the cgroup root_list RCU safe cgroup: Remove unnecessary list_empty()
2023-12-15kernfs: Convert kernfs_path_from_node_locked() from strlcpy() to strscpy()Kees Cook
One of the last remaining users of strlcpy() in the kernel is kernfs_path_from_node_locked(), which passes back the problematic "length we _would_ have copied" return value to indicate truncation. Convert the chain of all callers to use the negative return value (some of which already doing this explicitly). All callers were already also checking for negative return values, so the risk to missed checks looks very low. In this analysis, it was found that cgroup1_release_agent() actually didn't handle the "too large" condition, so this is technically also a bug fix. :) Here's the chain of callers, and resolution identifying each one as now handling the correct return value: kernfs_path_from_node_locked() kernfs_path_from_node() pr_cont_kernfs_path() returns void kernfs_path() sysfs_warn_dup() return value ignored cgroup_path() blkg_path() bfq_bic_update_cgroup() return value ignored TRACE_IOCG_PATH() return value ignored TRACE_CGROUP_PATH() return value ignored perf_event_cgroup() return value ignored task_group_path() return value ignored damon_sysfs_memcg_path_eq() return value ignored get_mm_memcg_path() return value ignored lru_gen_seq_show() return value ignored cgroup_path_from_kernfs_id() return value ignored cgroup_show_path() already converted "too large" error to negative value cgroup_path_ns_locked() cgroup_path_ns() bpf_iter_cgroup_show_fdinfo() return value ignored cgroup1_release_agent() wasn't checking "too large" error proc_cgroup_show() already converted "too large" to negative value Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Tejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Waiman Long <longman@redhat.com> Cc: <cgroups@vger.kernel.org> Co-developed-by: Azeem Shaikh <azeemshaikh38@gmail.com> Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com> Link: https://lore.kernel.org/r/20231116192127.1558276-3-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20231212211741.164376-3-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-15kernel/cgroup: use kernfs_create_dir_ns()Max Kellermann
By passing the fsugid to kernfs_create_dir_ns(), we don't need cgroup_kn_set_ugid() any longer. That function was added for exactly this purpose by commit 49957f8e2a43 ("cgroup: newly created dirs and files should be owned by the creator"). Eliminating this piece of duplicate code means we benefit from future improvements to kernfs_create_dir_ns(); for example, both are lacking S_ISGID support currently, which my next patch will add to kernfs_create_dir_ns(). It cannot (easily) be added to cgroup_kn_set_ugid() because we can't dereference struct kernfs_iattrs from there. -- v1 -> v2: 12-digit commit id Signed-off-by: Max Kellermann <max.kellermann@ionos.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20231208093310.297233-1-max.kellermann@ionos.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-07Merge tag 'cgroup-for-6.7-rc4-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fix from Tejun Heo: "Just one fix. Commit f5d39b020809 ("freezer,sched: Rewrite core freezer logic") changed how freezing state is recorded which made cgroup_freezing() disagree with the actual state of the task while thawing triggering a warning. Fix it by updating cgroup_freezing()" * tag 'cgroup-for-6.7-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup_freezer: cgroup_freezing: Check if not frozen
2023-12-06cgroup/cpuset: Include isolated cpuset CPUs in cpu_is_isolated() checkWaiman Long
Currently, the cpu_is_isolated() function checks only the statically isolated CPUs specified via the "isolcpus" and "nohz_full" kernel command line options. This function is used by vmstat and memcg to reduce interference with isolated CPUs by not doing stat flushing or scheduling works on those CPUs. Workloads running on isolated CPUs within isolated cpuset partitions should receive the same treatment to reduce unnecessary interference. This patch introduces a new cpuset_cpu_is_isolated() function to be called by cpu_is_isolated() so that the set of dynamically created cpuset isolated CPUs will be included in the check. Assuming that testing a bit in a cpumask is atomic, no synchronization primitive is currently used to synchronize access to the cpuset's isolated_cpus mask. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2023-12-01cgroup/rstat: Optimize cgroup_rstat_updated_list()Waiman Long
The current design of cgroup_rstat_cpu_pop_updated() is to traverse the updated tree in a way to pop out the leaf nodes first before their parents. This can cause traversal of multiple nodes before a leaf node can be found and popped out. IOW, a given node in the tree can be visited multiple times before the whole operation is done. So it is not very efficient and the code can be hard to read. With the introduction of cgroup_rstat_updated_list() to build a list of cgroups to be flushed first before any flushing operation is being done, we can optimize the way the updated tree nodes are being popped by pushing the parents first to the tail end of the list before their children. In this way, most updated tree nodes will be visited only once with the exception of the subtree root as we still need to go back to its parent and popped it out of its updated_children list. This also makes the code easier to read. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2023-11-28cgroup_freezer: cgroup_freezing: Check if not frozenTim Van Patten
__thaw_task() was recently updated to warn if the task being thawed was part of a freezer cgroup that is still currently freezing: void __thaw_task(struct task_struct *p) { ... if (WARN_ON_ONCE(freezing(p))) goto unlock; This has exposed a bug in cgroup1 freezing where when CGROUP_FROZEN is asserted, the CGROUP_FREEZING bits are not also cleared at the same time. Meaning, when a cgroup is marked FROZEN it continues to be marked FREEZING as well. This causes the WARNING to trigger, because cgroup_freezing() thinks the cgroup is still freezing. There are two ways to fix this: 1. Whenever FROZEN is set, clear FREEZING for the cgroup and all children cgroups. 2. Update cgroup_freezing() to also verify that FROZEN is not set. This patch implements option (2), since it's smaller and more straightforward. Signed-off-by: Tim Van Patten <timvp@google.com> Tested-by: Mark Hasemeyer <markhas@chromium.org> Fixes: f5d39b020809 ("freezer,sched: Rewrite core freezer logic") Cc: stable@vger.kernel.org # v6.1+ Signed-off-by: Tejun Heo <tj@kernel.org>
2023-11-28cgroup/cpuset: Expose cpuset.cpus.isolatedWaiman Long
The root-only cpuset.cpus.isolated control file shows the current set of isolated CPUs in isolated partitions. This control file is currently exposed only with the cgroup_debug boot command line option which also adds the ".__DEBUG__." prefix. This is actually a useful control file if users want to find out which CPUs are currently in an isolated state by the cpuset controller. Remove CFTYPE_DEBUG flag for this control file and make it available by default without any prefix. The test_cpuset_prs.sh test script and the cgroup-v2.rst documentation file are also updated accordingly. Minor code change is also made in test_cpuset_prs.sh to avoid false test failure when running on debug kernel. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2023-11-14sched: psi: fix unprivileged polling against cgroupsJohannes Weiner
519fabc7aaba ("psi: remove 500ms min window size limitation for triggers") breaks unprivileged psi polling on cgroups. Historically, we had a privilege check for polling in the open() of a pressure file in /proc, but were erroneously missing it for the open() of cgroup pressure files. When unprivileged polling was introduced in d82caa273565 ("sched/psi: Allow unprivileged polling of N*2s period"), it needed to filter privileges depending on the exact polling parameters, and as such moved the CAP_SYS_RESOURCE check from the proc open() callback to psi_trigger_create(). Both the proc files as well as cgroup files go through this during write(). This implicitly added the missing check for privileges required for HT polling for cgroups. When 519fabc7aaba ("psi: remove 500ms min window size limitation for triggers") followed right after to remove further restrictions on the RT polling window, it incorrectly assumed the cgroup privilege check was still missing and added it to the cgroup open(), mirroring what we used to do for proc files in the past. As a result, unprivileged poll requests that would be supported now get rejected when opening the cgroup pressure file for writing. Remove the cgroup open() check. psi_trigger_create() handles it. Fixes: 519fabc7aaba ("psi: remove 500ms min window size limitation for triggers") Reported-by: Luca Boccassi <bluca@debian.org> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Luca Boccassi <bluca@debian.org> Acked-by: Suren Baghdasaryan <surenb@google.com> Cc: stable@vger.kernel.org # 6.5+ Link: https://lore.kernel.org/r/20231026164114.2488682-1-hannes@cmpxchg.org