The patch titled
Subject: mm/oom_kill.c: syzbot: dump all threads upon global OOM
has been added to the -mm tree. Its filename is
syzbot-dump-all-threads-upon-global-oom.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/syzbot-dump-all-threads-upon-global-oom.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/syzbot-dump-all-threads-upon-global-oom.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Subject: mm/oom_kill.c: syzbot: dump all threads upon global OOM
syzbot is getting stalls with linux-next kernels because dump_tasks() from
out_of_memory() is printing 5600 tasks. Most of these tasks are syzbot
processes but syzbot is supposed not to create so many processes.
Therefore, let's start from checking what these tasks are doing. This
change will be removed after the bug is fixed.
Link: http://lkml.kernel.org/r/312c642d-559b-92c7-0377-d98ec416e0bd@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/oom_kill.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
--- a/mm/oom_kill.c~syzbot-dump-all-threads-upon-global-oom
+++ a/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"
@@ -446,6 +447,24 @@ static void dump_header(struct oom_contr
if (is_dump_unreclaim_slabs())
dump_unreclaimable_slab();
}
+#ifdef CONFIG_DEBUG_AID_FOR_SYZBOT
+ if (!is_sysrq_oom(oc) && !is_memcg_oom(oc)) {
+ struct task_struct *p;
+ unsigned int tasks = 0;
+
+ rcu_read_lock();
+ for_each_process(p) {
+ if (!(p->flags & PF_KTHREAD))
+ tasks++;
+ }
+ rcu_read_unlock();
+
+ if (tasks >= 1000) {
+ show_state();
+ panic("Out of memory with too many tasks.");
+ }
+ }
+#endif
if (sysctl_oom_dump_tasks)
dump_tasks(oc->memcg, oc->nodemask);
}
_
Patches currently in -mm which might be from penguin-kernel@xxxxxxxxxxxxxxxxxxx are
syzbot-dump-all-threads-upon-global-oom.patch
