linux_dsm_epyc7002/kernel/sched
Jens Axboe 18f855e574 sched/fair: Don't NUMA balance for kthreads
Stefano reported a crash with using SQPOLL with io_uring:

  BUG: kernel NULL pointer dereference, address: 00000000000003b0
  CPU: 2 PID: 1307 Comm: io_uring-sq Not tainted 5.7.0-rc7 #11
  RIP: 0010:task_numa_work+0x4f/0x2c0
  Call Trace:
   task_work_run+0x68/0xa0
   io_sq_thread+0x252/0x3d0
   kthread+0xf9/0x130
   ret_from_fork+0x35/0x40

which is task_numa_work() oopsing on current->mm being NULL.

The task work is queued by task_tick_numa(), which checks if current->mm is
NULL at the time of the call. But this state isn't necessarily persistent,
if the kthread is using use_mm() to temporarily adopt the mm of a task.

Change the task_tick_numa() check to exclude kernel threads in general,
as it doesn't make sense to attempt ot balance for kthreads anyway.

Reported-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/865de121-8190-5d30-ece5-3b097dc74431@kernel.dk
2020-05-26 18:34:58 +02:00
..
autogroup.c
autogroup.h
clock.c
completion.c completion: Use lockdep_assert_RT_in_threaded_ctx() in complete_all() 2020-03-23 18:40:25 +01:00
core.c sched/core: Fix reset-on-fork from RT with uclamp 2020-04-22 23:10:13 +02:00
cpuacct.c
cpudeadline.c
cpudeadline.h
cpufreq_schedutil.c
cpufreq.c
cpupri.c sched/rt: cpupri_find: Trigger a full search as fallback 2020-03-20 13:06:20 +01:00
cpupri.h sched/rt: Optimize cpupri_find() on non-heterogenous systems 2020-03-06 12:57:27 +01:00
cputime.c sched/vtime: Work around an unitialized variable warning 2020-04-15 11:06:50 +02:00
deadline.c sched/deadline: Make two functions static 2020-03-06 12:57:24 +01:00
debug.c sched/debug: Fix requested task uclamp values shown in procfs 2020-05-19 20:34:10 +02:00
fair.c sched/fair: Don't NUMA balance for kthreads 2020-05-26 18:34:58 +02:00
features.h
idle.c
isolation.c sched/isolation: Allow "isolcpus=" to skip unknown sub-parameters 2020-04-15 10:38:26 +02:00
loadavg.c
Makefile
membarrier.c
pelt.c sched/pelt: Add support to track thermal pressure 2020-03-06 12:57:17 +01:00
pelt.h sched/pelt: Add support to track thermal pressure 2020-03-06 12:57:17 +01:00
psi.c psi: Move PF_MEMSTALL out of task->flags 2020-03-20 13:06:19 +01:00
rt.c sched/rt: Remove unnecessary push for unfit tasks 2020-03-06 12:57:29 +01:00
sched-pelt.h
sched.h sched/core: Remove unused rq::last_load_update_tick 2020-04-08 11:35:23 +02:00
stats.c
stats.h psi: Move PF_MEMSTALL out of task->flags 2020-03-20 13:06:19 +01:00
stop_task.c
swait.c sched/swait: Prepare usage in completions 2020-03-21 16:00:23 +01:00
topology.c sched/topology: Don't enable EAS on SMT systems 2020-03-06 12:57:23 +01:00
wait_bit.c
wait.c