I found that it is not difficult to hit "oom_reaper: unable to reap pid:"
messages if the victim thread is doing copy_process(). Since I noticed
that it is likely helpful to show trace of unable to reap victim thread
for finding locations which should use killable wait, this patch does so.
[ 226.608508] oom_reaper: unable to reap pid:9261 (a.out)
[ 226.611971] a.out D13056 9261 6927 0x00100084
[ 226.615879] Call Trace:
[ 226.617926] ? __schedule+0x25f/0x780
[ 226.620559] schedule+0x2d/0x80
[ 226.623356] rwsem_down_write_failed+0x2bb/0x440
[ 226.626426] ? rwsem_down_write_failed+0x55/0x440
[ 226.629458] ? anon_vma_fork+0x124/0x150
[ 226.632679] call_rwsem_down_write_failed+0x13/0x20
[ 226.635884] down_write+0x49/0x60
[ 226.638867] ? copy_process.part.41+0x12f2/0x1fe0
[ 226.642042] copy_process.part.41+0x12f2/0x1fe0 /* i_mmap_lock_write() in dup_mmap() */
[ 226.645087] ? _do_fork+0xe6/0x560
[ 226.647991] _do_fork+0xe6/0x560
[ 226.650495] ? syscall_trace_enter+0x1a9/0x240
[ 226.653443] ? retint_user+0x18/0x18
[ 226.656601] ? page_fault+0x2f/0x50
[ 226.659159] ? trace_hardirqs_on_caller+0x11f/0x1b0
[ 226.662399] do_syscall_64+0x74/0x230
[ 226.664989] entry_SYSCALL_64_after_hwframe+0x42/0xb7
[ 380.525910] oom_reaper: unable to reap pid:6927 (a.out)
[ 380.529274] a.out R running task 13544 6927 1 0x00100084
[ 380.533264] Call Trace:
[ 380.535433] ? __schedule+0x25f/0x780
[ 380.538052] ? mark_held_locks+0x60/0x80
[ 380.540775] schedule+0x2d/0x80
[ 380.543258] schedule_timeout+0x1a4/0x350
[ 380.546053] ? __next_timer_interrupt+0xd0/0xd0
[ 380.549033] msleep+0x25/0x30
[ 380.551458] shrink_inactive_list+0x5b7/0x690
[ 380.554408] ? __lock_acquire+0x1f1/0xfd0
[ 380.557228] ? find_held_lock+0x2d/0x90
[ 380.559959] shrink_node_memcg+0x340/0x770
[ 380.562776] ? __lock_acquire+0x246/0xfd0
[ 380.565532] ? mem_cgroup_iter+0x121/0x4f0
[ 380.568337] ? mem_cgroup_iter+0x121/0x4f0
[ 380.571203] shrink_node+0xd8/0x370
[ 380.573745] do_try_to_free_pages+0xe3/0x390
[ 380.576759] try_to_free_pages+0xc8/0x110
[ 380.579476] __alloc_pages_slowpath+0x28a/0x8d9
[ 380.582639] __alloc_pages_nodemask+0x21d/0x260
[ 380.585662] new_slab+0x558/0x760
[ 380.588188] ___slab_alloc+0x353/0x6f0
[ 380.590962] ? copy_process.part.41+0x121f/0x1fe0
[ 380.594008] ? find_held_lock+0x2d/0x90
[ 380.596750] ? copy_process.part.41+0x121f/0x1fe0
[ 380.599852] __slab_alloc+0x41/0x7a
[ 380.602469] ? copy_process.part.41+0x121f/0x1fe0
[ 380.605607] kmem_cache_alloc+0x1a6/0x1f0
[ 380.608528] copy_process.part.41+0x121f/0x1fe0 /* kmem_cache_alloc(GFP_KERNEL) in dup_mmap() */
[ 380.611613] ? _do_fork+0xe6/0x560
[ 380.614299] _do_fork+0xe6/0x560
[ 380.616752] ? syscall_trace_enter+0x1a9/0x240
[ 380.619813] ? retint_user+0x18/0x18
[ 380.622588] ? page_fault+0x2f/0x50
[ 380.625184] ? trace_hardirqs_on_caller+0x11f/0x1b0
[ 380.628841] do_syscall_64+0x74/0x230
[ 380.631660] entry_SYSCALL_64_after_hwframe+0x42/0xb7
[ 600.285293] oom_reaper: unable to reap pid:7550 (a.out)
[ 600.289112] a.out D13104 7550 6931 0x00100084
[ 600.292918] Call Trace:
[ 600.295506] ? __schedule+0x25f/0x780
[ 600.298614] ? __lock_acquire+0x246/0xfd0
[ 600.301879] schedule+0x2d/0x80
[ 600.304623] schedule_timeout+0x1fd/0x350
[ 600.307633] ? find_held_lock+0x2d/0x90
[ 600.310909] ? mark_held_locks+0x60/0x80
[ 600.314001] ? _raw_spin_unlock_irq+0x24/0x30
[ 600.317382] wait_for_completion+0xab/0x130
[ 600.320579] ? wake_up_q+0x70/0x70
[ 600.323419] flush_work+0x1bd/0x260
[ 600.326434] ? flush_work+0x174/0x260
[ 600.329332] ? destroy_worker+0x90/0x90
[ 600.332301] drain_all_pages+0x16d/0x1e0
[ 600.335464] __alloc_pages_slowpath+0x443/0x8d9
[ 600.338743] __alloc_pages_nodemask+0x21d/0x260
[ 600.342178] new_slab+0x558/0x760
[ 600.344861] ___slab_alloc+0x353/0x6f0
[ 600.347744] ? copy_process.part.41+0x121f/0x1fe0
[ 600.351213] ? find_held_lock+0x2d/0x90
[ 600.354119] ? copy_process.part.41+0x121f/0x1fe0
[ 600.357491] __slab_alloc+0x41/0x7a
[ 600.360206] ? copy_process.part.41+0x121f/0x1fe0
[ 600.363480] kmem_cache_alloc+0x1a6/0x1f0
[ 600.366579] copy_process.part.41+0x121f/0x1fe0 /* kmem_cache_alloc(GFP_KERNEL) in dup_mmap() */
[ 600.369761] ? _do_fork+0xe6/0x560
[ 600.372382] _do_fork+0xe6/0x560
[ 600.375142] ? syscall_trace_enter+0x1a9/0x240
[ 600.378258] ? retint_user+0x18/0x18
[ 600.380978] ? page_fault+0x2f/0x50
[ 600.383814] ? trace_hardirqs_on_caller+0x11f/0x1b0
[ 600.387096] do_syscall_64+0x74/0x230
[ 600.389928] entry_SYSCALL_64_after_hwframe+0x42/0xb7
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
---
mm/oom_kill.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 5336985..900300c 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -41,6 +41,7 @@
#include <linux/kthread.h>
#include <linux/init.h>
#include <linux/mmu_notifier.h>
+#include <linux/sched/debug.h>
#include <asm/tlb.h>
#include "internal.h"
@@ -596,6 +597,7 @@ static void oom_reap_task(struct task_struct *tsk)
pr_info("oom_reaper: unable to reap pid:%d (%s)\n",
task_pid_nr(tsk), tsk->comm);
+ sched_show_task(tsk);
debug_show_all_locks();
done:
--
1.8.3.1
