- Aug 08, 2019
-
-
Dave Chiluk authored
It has been observed, that highly-threaded, non-cpu-bound applications running under cpu.cfs_quota_us constraints can hit a high percentage of periods throttled while simultaneously not consuming the allocated amount of quota. This use case is typical of user-interactive non-cpu bound applications, such as those running in kubernetes or mesos when run on multiple cpu cores. This has been root caused to cpu-local run queue being allocated per cpu bandwidth slices, and then not fully using that slice within the period. At which point the slice and quota expires. This expiration of unused slice results in applications not being able to utilize the quota for which they are allocated. The non-expiration of per-cpu slices was recently fixed by 'commit 512ac999 ("sched/fair: Fix bandwidth timer clock drift condition")'. Prior to that it appears that this had been broken since at least 'commit 51f2176d ("sched/fair: Fix unlocked reads of some cfs_b->quota/period")' which was introduced in v3.16-rc1 in 2014. That added the following conditional which resulted in slices never being expired. if (cfs_rq->runtime_expires != cfs_b->runtime_expires) { /* extend local deadline, drift is bounded above by 2 ticks */ cfs_rq->runtime_expires += TICK_NSEC; Because this was broken for nearly 5 years, and has recently been fixed and is now being noticed by many users running kubernetes (https://github.com/kubernetes/kubernetes/issues/67577) it is my opinion that the mechanisms around expiring runtime should be removed altogether. This allows quota already allocated to per-cpu run-queues to live longer than the period boundary. This allows threads on runqueues that do not use much CPU to continue to use their remaining slice over a longer period of time than cpu.cfs_period_us. However, this helps prevent the above condition of hitting throttling while also not fully utilizing your cpu quota. This theoretically allows a machine to use slightly more than its allotted quota in some periods. This overflow would be bounded by the remaining quota left on each per-cpu runqueueu. This is typically no more than min_cfs_rq_runtime=1ms per cpu. For CPU bound tasks this will change nothing, as they should theoretically fully utilize all of their quota in each period. For user-interactive tasks as described above this provides a much better user/application experience as their cpu utilization will more closely match the amount they requested when they hit throttling. This means that cpu limits no longer strictly apply per period for non-cpu bound applications, but that they are still accurate over longer timeframes. This greatly improves performance of high-thread-count, non-cpu bound applications with low cfs_quota_us allocation on high-core-count machines. In the case of an artificial testcase (10ms/100ms of quota on 80 CPU machine), this commit resulted in almost 30x performance improvement, while still maintaining correct cpu quota restrictions. That testcase is available at https://github.com/indeedeng/fibtest. Fixes: 512ac999 ("sched/fair: Fix bandwidth timer clock drift condition") Signed-off-by:
Dave Chiluk <chiluk+linux@indeed.com> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Phil Auld <pauld@redhat.com> Reviewed-by:
Ben Segall <bsegall@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: John Hammond <jhammond@indeed.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kyle Anderson <kwa@yelp.com> Cc: Gabriel Munos <gmunoz@netflix.com> Cc: Peter Oskolkov <posk@posk.io> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Brendan Gregg <bgregg@netflix.com> Link: https://lkml.kernel.org/r/1563900266-19734-2-git-send-email-chiluk+linux@indeed.com
-
Peter Zijlstra authored
The current active_mm reference counting is confusing and sub-optimal. Rewrite the code to explicitly consider the 4 separate cases: user -> user When switching between two user tasks, all we need to consider is switch_mm(). user -> kernel When switching from a user task to a kernel task (which doesn't have an associated mm) we retain the last mm in our active_mm. Increment a reference count on active_mm. kernel -> kernel When switching between kernel threads, all we need to do is pass along the active_mm reference. kernel -> user When switching between a kernel and user task, we must switch from the last active_mm to the next mm, hoping of course that these are the same. Decrement a reference on the active_mm. The code keeps a different order, because as you'll note, both 'to user' cases require switch_mm(). And where the old code would increment/decrement for the 'kernel -> kernel' case, the new code observes this is a neutral operation and avoids touching the reference count. Signed-off-by:Rik van Riel <riel@surriel.com> Reviewed-by:
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: luto@kernel.org
-
Peter Zijlstra authored
A rather embarrasing mistake had us call sched_setscheduler() before initializing the parameters passed to it. Fixes: 1a763fd7 ("rcu/tree: Call setschedule() gp ktread to SCHED_FIFO outside of atomic region") Signed-off-by:
Paul E. McKenney <paulmck@linux.ibm.com> Cc: Juri Lelli <juri.lelli@redhat.com>
-
- Jul 25, 2019
-
-
Qian Cai authored
Compiling a kernel with both FAIR_GROUP_SCHED=n and RT_GROUP_SCHED=n will generate a compiler warning: kernel/sched/core.c: In function 'sched_init': kernel/sched/core.c:5906:32: warning: variable 'ptr' set but not used It is unnecessary to have both "alloc_size" and "ptr", so just combine them. Signed-off-by:
Qian Cai <cai@lca.pw> Signed-off-by:
Ingo Molnar <mingo@kernel.org>
-
Juri Lelli authored
On !CONFIG_RT_GROUP_SCHED configurations it is currently not possible to move RT tasks between cgroups to which CPU controller has been attached; but it is oddly possible to first move tasks around and then make them RT (setschedule to FIFO/RR). E.g.: # mkdir /sys/fs/cgroup/cpu,cpuacct/group1 # chrt -fp 10 $$ # echo $$ > /sys/fs/cgroup/cpu,cpuacct/group1/tasks bash: echo: write error: Invalid argument # chrt -op 0 $$ # echo $$ > /sys/fs/cgroup/cpu,cpuacct/group1/tasks # chrt -fp 10 $$ # cat /sys/fs/cgroup/cpu,cpuacct/group1/tasks 2345 2598 # chrt -p 2345 pid 2345's current scheduling policy: SCHED_FIFO pid 2345's current scheduling priority: 10 Also, as Michal noted, it is currently not possible to enable CPU controller on unified hierarchy with !CONFIG_RT_GROUP_SCHED (if there are any kernel RT threads in root cgroup, they can't be migrated to the newly created CPU controller's root in cgroup_update_dfl_csses()). Existing code comes with a comment saying the "we don't support RT-tasks being in separate groups". Such comment is however stale and belongs to pre-RT_GROUP_SCHED times. Also, it doesn't make much sense for !RT_GROUP_ SCHED configurations, since checks related to RT bandwidth are not performed at all in these cases. Make moving RT tasks between CPU controller groups viable by removing special case check for RT (and DEADLINE) tasks. Signed-off-by:
Juri Lelli <juri.lelli@redhat.com> Signed-off-by:
Michal Koutný <mkoutny@suse.com> Reviewed-by:
Daniel Bristot de Oliveira <bristot@redhat.com> Acked-by:
Tejun Heo <tj@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: lizefan@huawei.com Cc: longman@redhat.com Cc: luca.abeni@santannapisa.it Cc: rostedt@goodmis.org Link: https://lkml.kernel.org/r/20190719063455.27328-1-juri.lelli@redhat.com Signed-off-by:
-
Juri Lelli authored
No synchronisation mechanism exists between the cpuset subsystem and calls to function __sched_setscheduler(). As such, it is possible that new root domains are created on the cpuset side while a deadline acceptance test is carried out in __sched_setscheduler(), leading to a potential oversell of CPU bandwidth. Grab cpuset_rwsem read lock from core scheduler, so to prevent situations such as the one described above from happening. The only exception is normalize_rt_tasks() which needs to work under tasklist_lock and can't therefore grab cpuset_rwsem. We are fine with this, as this function is only called by sysrq and, if that gets triggered, DEADLINE guarantees are already gone out of the window anyway. Tested-by:
Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by:
-
Juri Lelli authored
sched_setscheduler() needs to acquire cpuset_rwsem, but it is currently called from an invalid (atomic) context by rcu_spawn_gp_kthread(). Fix that by simply moving sched_setscheduler_nocheck() call outside of the atomic region, as it doesn't actually require to be guarded by rcu_node lock. Suggested-by:
-
Juri Lelli authored
cpuset_rwsem is going to be acquired from sched_setscheduler() with a following patch. There are however paths (e.g., spawn_ksoftirqd) in which sched_scheduler() is eventually called while holding hotplug lock; this creates a dependecy between hotplug lock (to be always acquired first) and cpuset_rwsem (to be always acquired after hotplug lock). Fix paths which currently take the two locks in the wrong order (after a following patch is applied). Tested-by:
-
Juri Lelli authored
Holding cpuset_mutex means that cpusets are stable (only the holder can make changes) and this is required for fixing a synchronization issue between cpusets and scheduler core. However, grabbing cpuset_mutex from setscheduler() hotpath (as implemented in a later patch) is a no-go, as it would create a bottleneck for tasks concurrently calling setscheduler(). Convert cpuset_mutex to be a percpu_rwsem (cpuset_rwsem), so that setscheduler() will then be able to read lock it and avoid concurrency issues. Tested-by:
-
Juri Lelli authored
If a task happens to be throttled while the CPU it was running on gets hotplugged off, the bandwidth associated with the task is not correctly migrated with it when the replenishment timer fires (offline_migration). Fix things up, for this_bw, running_bw and total_bw, when replenishment timer fires and task is migrated (dl_task_offline_migration()). Tested-by:
-
Mathieu Poirier authored
When the topology of root domains is modified by CPUset or CPUhotplug operations information about the current deadline bandwidth held in the root domain is lost. This patch addresses the issue by recalculating the lost deadline bandwidth information by circling through the deadline tasks held in CPUsets and adding their current load to the root domain they are associated with. Tested-by:
Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by:
-
Mathieu Poirier authored
Calls to task_rq_unlock() are done several times in the __sched_setscheduler() function. This is fine when only the rq lock needs to be handled but not so much when other locks come into play. This patch streamlines the release of the rq lock so that only one location need to be modified when dealing with more than one lock. No change of functionality is introduced by this patch. Tested-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Acked-by:
-
Mathieu Poirier authored
Introduce the partition_sched_domains_locked() function by taking the mutex locking code out of the original function. That way the work done by partition_sched_domains_locked() can be reused without dropping the mutex lock. No change of functionality is introduced by this patch. Tested-by:
-
Viresh Kumar authored
The same formula to check utilization against capacity (after considering capacity_margin) is already used at 5 different locations. This patch creates a new macro, fits_capacity(), which can be used from all these locations without exposing the details of it and hence simplify code. All the 5 code locations are updated as well to use it.. Signed-off-by:
Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by:
-
Wanpeng Li authored
In real product setup, there will be houseeking CPUs in each nodes, it is prefer to do housekeeping from local node, fallback to global online cpumask if failed to find houseeking CPU from local node. Signed-off-by:
Wanpeng Li <wanpengli@tencent.com> Signed-off-by:
Frederic Weisbecker <frederic@kernel.org> Reviewed-by:
Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/1561711901-4755-2-git-send-email-wanpengli@tencent.com Signed-off-by:
-
Yi Wang authored
sched_info_on() is called with unlikely hint, however, the test is to be a constant(1) on which compiler will do nothing when make defconfig, so remove the hint. Also, fix a lack of {}. Signed-off-by:Yi Wang <wang.yi59@zte.com.cn> Signed-off-by:
-
Matthew Wilcox (Oracle) authored
Returning the pointer that was passed in allows us to write slightly more idiomatic code. Convert a few users. Signed-off-by:
Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by:
-
Viresh Kumar authored
We try to find an idle CPU to run the next task, but in case we don't find an idle CPU it is better to pick a CPU which will run the task the soonest, for performance reason. A CPU which isn't idle but has only SCHED_IDLE activity queued on it should be a good target based on this criteria as any normal fair task will most likely preempt the currently running SCHED_IDLE task immediately. In fact, choosing a SCHED_IDLE CPU over a fully idle one shall give better results as it should be able to run the task sooner than an idle CPU (which requires to be woken up from an idle state). This patch updates both fast and slow paths with this optimization. Signed-off-by:
-
Viresh Kumar authored
Track how many tasks are present with SCHED_IDLE policy in each cfs_rq. This will be used by later commits. Signed-off-by:
-
Paul E. McKenney authored
time/tick-broadcast: Fix tick_broadcast_offline() lockdep complaint The TASKS03 and TREE04 rcutorture scenarios produce the following lockdep complaint: WARNING: inconsistent lock state 5.2.0-rc1+ #513 Not tainted -------------------------------- inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. migration/1/14 [HC0[0]:SC0[0]:HE1:SE1] takes: (____ptrval____) (tick_broadcast_lock){?...}, at: tick_broadcast_offline+0xf/0x70 {IN-HARDIRQ-W} state was registered at: lock_acquire+0xb0/0x1c0 _raw_spin_lock_irqsave+0x3c/0x50 tick_broadcast_switch_to_oneshot+0xd/0x40 tick_switch_to_oneshot+0x4f/0xd0 hrtimer_run_queues+0xf3/0x130 run_local_timers+0x1c/0x50 update_process_times+0x1c/0x50 tick_periodic+0x26/0xc0 tick_handle_periodic+0x1a/0x60 smp_apic_timer_interrupt+0x80/0x2a0 apic_timer_interrupt+0xf/0x20 _raw_spin_unlock_irqrestore+0x4e/0x60 rcu_nocb_gp_kthread+0x15d/0x590 kthread+0xf3/0x130 ret_from_fork+0x3a/0x50 irq event stamp: 171 hardirqs last enabled at (171): [<ffffffff8a201a37>] trace_hardirqs_on_thunk+0x1a/0x1c hardirqs last disabled at (170): [<ffffffff8a201a53>] trace_hardirqs_off_thunk+0x1a/0x1c softirqs last enabled at (0): [<ffffffff8a264ee0>] copy_process.part.56+0x650/0x1cb0 softirqs last disabled at (0): [<0000000000000000>] 0x0 [...] To reproduce, run the following rcutorture test: $ tools/testing/selftests/rcutorture/bin/kvm.sh --duration 5 --kconfig "CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y" --configs "TASKS03 TREE04" It turns out that tick_broadcast_offline() was an innocent bystander. After all, interrupts are supposed to be disabled throughout take_cpu_down(), and therefore should have been disabled upon entry to tick_offline_cpu() and thus to tick_broadcast_offline(). This suggests that one of the CPU-hotplug notifiers was incorrectly enabling interrupts, and leaving them enabled on return. Some debugging code showed that the culprit was sched_cpu_dying(). It had irqs enabled after return from sched_tick_stop(). Which in turn had irqs enabled after return from cancel_delayed_work_sync(). Which is a wrapper around __cancel_work_timer(). Which can sleep in the case where something else is concurrently trying to cancel the same delayed work, and as Thomas Gleixner pointed out on IRC, sleeping is a decidedly bad idea when you are invoked from take_cpu_down(), regardless of the state you leave interrupts in upon return. Code inspection located no reason why the delayed work absolutely needed to be canceled from sched_tick_stop(): The work is not bound to the outgoing CPU by design, given that the whole point is to collect statistics without disturbing the outgoing CPU. This commit therefore simply drops the cancel_delayed_work_sync() from sched_tick_stop(). Instead, a new ->state field is added to the tick_work structure so that the delayed-work handler function sched_tick_remote() can avoid reposting itself. A cpu_is_offline() check is also added to sched_tick_remote() to avoid mucking with the state of an offlined CPU (though it does appear safe to do so). The sched_tick_start() and sched_tick_stop() functions also update ->state, and sched_tick_start() also schedules the delayed work if ->state indicates that it is not already in flight. Signed-off-by: -
Vincent Guittot authored
The load_balance() has a dedicated mecanism to detect when an imbalance is due to CPU affinity and must be handled at parent level. In this case, the imbalance field of the parent's sched_group is set. The description of sg_imbalanced() gives a typical example of two groups of 4 CPUs each and 4 tasks each with a cpumask covering 1 CPU of the first group and 3 CPUs of the second group. Something like: { 0 1 2 3 } { 4 5 6 7 } * * * * But the load_balance fails to fix this UC on my octo cores system made of 2 clusters of quad cores. Whereas the load_balance is able to detect that the imbalanced is due to CPU affinity, it fails to fix it because the imbalance field is cleared before letting parent level a chance to run. In fact, when the imbalance is detected, the load_balance reruns without the CPU with pinned tasks. But there is no other running tasks in the situation described above and everything looks balanced this time so the imbalance field is immediately cleared. The imbalance field should not be cleared if there is no other task to move when the imbalance is detected. Signed-off-by:Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by:
-
Valentin Schneider authored
There are no callers outside of fair.c. Signed-off-by:
Valentin Schneider <valentin.schneider@arm.com> Signed-off-by:
-
Valentin Schneider authored
We only need to set the callback_head worker function once, do it during sched_fork(). While at it, move the comment regarding double task_work addition to init_numa_balancing(), since the double add sentinel is first set there. Suggested-by:
-
Valentin Schneider authored
To reference task_numa_work() from within init_numa_balancing(), we need the former to be declared before the latter. Do just that. This is a pure code movement. Signed-off-by:
-
Jann Horn authored
The old code used RCU annotations and accessors inconsistently for ->numa_group, which can lead to use-after-frees and NULL dereferences. Let all accesses to ->numa_group use proper RCU helpers to prevent such issues. Signed-off-by:
Jann Horn <jannh@google.com> Signed-off-by:
-
Jann Horn authored
When going through execve(), zero out the NUMA fault statistics instead of freeing them. During execve, the task is reachable through procfs and the scheduler. A concurrent /proc/*/sched reader can read data from a freed ->numa_faults allocation (confirmed by KASAN) and write it back to userspace. I believe that it would also be possible for a use-after-free read to occur through a race between a NUMA fault and execve(): task_numa_fault() can lead to task_numa_compare(), which invokes task_weight() on the currently running task of a different CPU. Another way to fix this would be to make ->numa_faults RCU-managed or add extra locking, but it seems easier to wipe the NUMA fault statistics on execve. Signed-off-by:
-
- Jul 23, 2019
-
-
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull preemption Kconfig fix from Thomas Gleixner: "The PREEMPT_RT stub config renamed PREEMPT to PREEMPT_LL and defined PREEMPT outside of the menu and made it selectable by both PREEMPT_LL and PREEMPT_RT. Stupid me missed that 114 defconfigs select CONFIG_PREEMPT which obviously can't work anymore. oldconfig builds are affected as well, but it's more obvious as the user gets asked. [old]defconfig silently fixes it up and selects PREEMPT_NONE. Unbreak it by undoing the rename and adding a intermediate config symbol which is selected by both PREEMPT and PREEMPT_RT. That requires to chase down a few #ifdefs, but it's better than tweaking 114 defconfigs and annoying users" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/rt, Kconfig: Unbreak def/oldconfig with CONFIG_PREEMPT=y
-
git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linuxLinus Torvalds authored
Pull pidfd polling fix from Christian Brauner: "A fix for pidfd polling. It ensures that the task's exit state is visible to all waiters" * tag 'for-linus-20190722' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: pidfd: fix a poll race when setting exit_state
-
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linuxLinus Torvalds authored
Pull btrfs fixes from David Sterba: - fixes for leaks caused by recently merged patches - one build fix - a fix to prevent mixing of incompatible features * tag 'for-5.3-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: don't leak extent_map in btrfs_get_io_geometry() btrfs: free checksum hash on in close_ctree btrfs: Fix build error while LIBCRC32C is module btrfs: inode: Don't compress if NODATASUM or NODATACOW set
-
Thomas Gleixner authored
The merge of the CONFIG_PREEMPT_RT stub renamed CONFIG_PREEMPT to CONFIG_PREEMPT_LL which causes all defconfigs which have CONFIG_PREEMPT=y set to fall back to CONFIG_PREEMPT_NONE because CONFIG_PREEMPT depends on the preemption mode choice wich defaults to NONE. This also affects oldconfig builds. So rather than changing 114 defconfig files and being an annoyance to users, revert the rename and select a new config symbol PREEMPTION. That keeps everything working smoothly and the revelant ifdef's are going to be fixed up step by step. Reported-by:
Mark Rutland <mark.rutland@arm.com> Fixes: a50a3f4b ("sched/rt, Kconfig: Introduce CONFIG_PREEMPT_RT") Signed-off-by:
Thomas Gleixner <tglx@linutronix.de>
-
git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediaLinus Torvalds authored
Pull media fixes from Mauro Carvalho Chehab: "For two regressions in media core: - v4l2-subdev: fix regression in check_pad() - videodev2.h: change V4L2_PIX_FMT_BGRA444 define: fourcc was already in use" * tag 'media/v5.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: media: videodev2.h: change V4L2_PIX_FMT_BGRA444 define: fourcc was already in use media: v4l2-subdev: fix regression in check_pad()
-
- Jul 22, 2019
-
-
git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds authored
Pull networking fixes from David Miller: 1) Several netfilter fixes including a nfnetlink deadlock fix from Florian Westphal and fix for dropping VRF packets from Miaohe Lin. 2) Flow offload fixes from Pablo Neira Ayuso including a fix to restore proper block sharing. 3) Fix r8169 PHY init from Thomas Voegtle. 4) Fix memory leak in mac80211, from Lorenzo Bianconi. 5) Missing NULL check on object allocation in cxgb4, from Navid Emamdoost. 6) Fix scaling of RX power in sfp phy driver, from Andrew Lunn. 7) Check that there is actually an ip header to access in skb->data in VRF, from Peter Kosyh. 8) Remove spurious rcu unlock in hv_netvsc, from Haiyang Zhang. 9) One more tweak the the TCP fragmentation memory limit changes, to be less harmful to applications setting small SO_SNDBUF values. From Eric Dumazet. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (40 commits) tcp: be more careful in tcp_fragment() hv_netvsc: Fix extra rcu_read_unlock in netvsc_recv_callback() vrf: make sure skb->data contains ip header to make routing connector: remove redundant input callback from cn_dev qed: Prefer pcie_capability_read_word() igc: Prefer pcie_capability_read_word() cxgb4: Prefer pcie_capability_read_word() be2net: Synchronize be_update_queues with dev_watchdog bnx2x: Prevent load reordering in tx completion processing net: phy: sfp: hwmon: Fix scaling of RX power net: sched: verify that q!=NULL before setting q->flags chelsio: Fix a typo in a function name allocate_flower_entry: should check for null deref net: hns3: typo in the name of a constant kbuild: add net/netfilter/nf_tables_offload.h to header-test blacklist. tipc: Fix a typo mac80211: don't warn about CW params when not using them mac80211: fix possible memory leak in ieee80211_assign_beacon nl80211: fix NL80211_HE_MAX_CAPABILITY_LEN nl80211: fix VENDOR_CMD_RAW_DATA ... -
Suren Baghdasaryan authored
There is a race between reading task->exit_state in pidfd_poll and writing it after do_notify_parent calls do_notify_pidfd. Expected sequence of events is: CPU 0 CPU 1 ------------------------------------------------ exit_notify do_notify_parent do_notify_pidfd tsk->exit_state = EXIT_DEAD pidfd_poll if (tsk->exit_state) However nothing prevents the following sequence: CPU 0 CPU 1 ------------------------------------------------ exit_notify do_notify_parent do_notify_pidfd pidfd_poll if (tsk->exit_state) tsk->exit_state = EXIT_DEAD This causes a polling task to wait forever, since poll blocks because exit_state is 0 and the waiting task is not notified again. A stress test continuously doing pidfd poll and process exits uncovered this bug. To fix it, we make sure that the task's exit_state is always set before calling do_notify_pidfd. Fixes: b53b0b9d ("pidfd: add polling support") Cc: kernel-team@android.com Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by:Suren Baghdasaryan <surenb@google.com> Signed-off-by:
Joel Fernandes (Google) <joel@joelfernandes.org> Link: https://lore.kernel.org/r/20190717172100.261204-1-joel@joelfernandes.org [christian@brauner.io: adapt commit message and drop unneeded changes from wait_task_zombie] Signed-off-by:
Christian Brauner <christian@brauner.io>
-
Eric Dumazet authored
Some applications set tiny SO_SNDBUF values and expect TCP to just work. Recent patches to address CVE-2019-11478 broke them in case of losses, since retransmits might be prevented. We should allow these flows to make progress. This patch allows the first and last skb in retransmit queue to be split even if memory limits are hit. It also adds the some room due to the fact that tcp_sendmsg() and tcp_sendpage() might overshoot sk_wmem_queued by about one full TSO skb (64KB size). Note this allowance was already present in stable backports for kernels < 4.15 Note for < 4.15 backports : tcp_rtx_queue_tail() will probably look like : static inline struct sk_buff *tcp_rtx_queue_tail(const struct sock *sk) { struct sk_buff *skb = tcp_send_head(sk); return skb ? tcp_write_queue_prev(sk, skb) : tcp_write_queue_tail(sk); } Fixes: f070ef2a ("tcp: tcp_fragment() should apply sane memory limits") Signed-off-by:Eric Dumazet <edumazet@google.com> Reported-by: Andrew ...
-
Haiyang Zhang authored
There is an extra rcu_read_unlock left in netvsc_recv_callback(), after a previous patch that removes RCU from this function. This patch removes the extra RCU unlock. Fixes: 345ac089 ("hv_netvsc: pass netvsc_device to receive callback") Signed-off-by:
Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
-
Linus Torvalds authored
-
Peter Kosyh authored
vrf_process_v4_outbound() and vrf_process_v6_outbound() do routing using ip/ipv6 addresses, but don't make sure the header is available in skb->data[] (skb_headlen() is less then header size). Case: 1) igb driver from intel. 2) Packet size is greater then 255. 3) MPLS forwards to VRF device. So, patch adds pskb_may_pull() calls in vrf_process_v4/v6_outbound() functions. Signed-off-by:
Peter Kosyh <p.kosyh@gmail.com> Reviewed-by:
David Ahern <dsa@cumulusnetworks.com> Signed-off-by:
-
Vasily Averin authored
A small cleanup: this callback is never used. Originally fixed by Stanislav Kinsburskiy <skinsbursky@virtuozzo.com> for OpenVZ7 bug OVZ-6877 cc: stanislav.kinsburskiy@gmail.com Signed-off-by:
Vasily Averin <vvs@virtuozzo.com> Signed-off-by:
-
Frederick Lawler authored
Commit 8c0d3a02 ("PCI: Add accessors for PCI Express Capability") added accessors for the PCI Express Capability so that drivers didn't need to be aware of differences between v1 and v2 of the PCI Express Capability. Replace pci_read_config_word() and pci_write_config_word() calls with pcie_capability_read_word() and pcie_capability_write_word(). Signed-off-by:
Frederick Lawler <fred@fredlawl.com> Acked-by:
Michal <Kalderon <michal.kalderon@marvell.com> Signed-off-by:
-
Frederick Lawler authored
Commit 8c0d3a02 ("PCI: Add accessors for PCI Express Capability") added accessors for the PCI Express Capability so that drivers didn't need to be aware of differences between v1 and v2 of the PCI Express Capability. Replace pci_read_config_word() and pci_write_config_word() calls with pcie_capability_read_word() and pcie_capability_write_word(). Signed-off-by:
-
