From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: mhocko@kernel.org
Cc: rientjes@google.com, oleg@redhat.com,
torvalds@linux-foundation.org, kwalker@redhat.com, cl@linux.com,
akpm@linux-foundation.org, hannes@cmpxchg.org,
vdavydov@parallels.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, skozina@redhat.com
Subject: Re: Can't we use timeout based OOM warning/killing?
Date: Tue, 6 Oct 2015 23:51:49 +0900 [thread overview]
Message-ID: <201510062351.JHJ57310.VFQLFHFOJtSMOO@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <201510031502.BJD59536.HFJMtQOOLFFVSO@I-love.SAKURA.ne.jp>
Tetsuo Handa wrote:
> Sorry. This was my misunderstanding. But I still think that we need to be
> prepared for cases where zapping OOM victim's mm approach fails.
> ( http://lkml.kernel.org/r/201509242050.EHE95837.FVFOOtMQHLJOFS@I-love.SAKURA.ne.jp )
I tested whether it is easy/difficult to make zapping OOM victim's mm
approach fail. The result seems that not difficult to make it fail.
---------- Reproducer start ----------
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sched.h>
#include <sys/mman.h>
static int reader(void *unused)
{
char c;
int fd = open("/proc/self/cmdline", O_RDONLY);
while (pread(fd, &c, 1, 0) == 1);
return 0;
}
static int writer(void *unused)
{
const int fd = open("/proc/self/exe", O_RDONLY);
static void *ptr[10000];
int i;
sleep(2);
while (1) {
for (i = 0; i < 10000; i++)
ptr[i] = mmap(NULL, 4096, PROT_READ, MAP_PRIVATE, fd,
0);
for (i = 0; i < 10000; i++)
munmap(ptr[i], 4096);
}
return 0;
}
int main(int argc, char *argv[])
{
int zero_fd = open("/dev/zero", O_RDONLY);
char *buf = NULL;
unsigned long size = 0;
int i;
for (size = 1048576; size < 512UL * (1 << 30); size <<= 1) {
char *cp = realloc(buf, size);
if (!cp) {
size >>= 1;
break;
}
buf = cp;
}
for (i = 0; i < 100; i++) {
clone(reader, malloc(1024) + 1024, CLONE_THREAD | CLONE_SIGHAND | CLONE_VM,
NULL);
}
clone(writer, malloc(1024) + 1024, CLONE_THREAD | CLONE_SIGHAND | CLONE_VM, NULL);
read(zero_fd, buf, size); /* Will cause OOM due to overcommit */
return * (char *) NULL; /* Kill all threads. */
}
---------- Reproducer end ----------
(I wrote this program for trying to mimic a trouble that a customer's system
hung up with a lot of ps processes blocked at reading /proc/pid/ entries
due to unkillable down_read(&mm->mmap_sem) in __access_remote_vm(). Though
I couldn't identify what function was holding the mmap_sem for writing...)
Uptime > 429 of http://I-love.SAKURA.ne.jp/tmp/serial-20151006.txt.xz showed
a OOM livelock that
(1) thread group leader is blocked at down_read(&mm->mmap_sem) in exit_mm()
called from do_exit().
(2) writer thread is blocked at down_write(&mm->mmap_sem) in vm_mmap_pgoff()
called from SyS_mmap_pgoff() called from SyS_mmap().
(3) many reader threads are blocking the writer thread because of
down_read(&mm->mmap_sem) called from proc_pid_cmdline_read().
(4) while the thread group leader is blocked at down_read(&mm->mmap_sem),
some of the reader threads are trying to allocate memory via page fault.
So, zapping the first OOM victim's mm might fail by chance.
--
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next prev parent reply other threads:[~2015-10-06 14:52 UTC|newest]
Thread overview: 109+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-17 17:59 [PATCH] mm/oom_kill.c: don't kill TASK_UNINTERRUPTIBLE tasks Kyle Walker
2015-09-17 19:22 ` Oleg Nesterov
2015-09-18 15:41 ` Christoph Lameter
2015-09-18 16:24 ` Oleg Nesterov
2015-09-18 16:39 ` Tetsuo Handa
2015-09-18 16:54 ` Oleg Nesterov
2015-09-18 17:00 ` Christoph Lameter
2015-09-18 19:07 ` Oleg Nesterov
2015-09-18 19:19 ` Christoph Lameter
2015-09-18 21:28 ` Kyle Walker
2015-09-18 22:07 ` Christoph Lameter
2015-09-19 8:32 ` Michal Hocko
2015-09-19 14:33 ` Tetsuo Handa
2015-09-19 15:51 ` Michal Hocko
2015-09-21 23:33 ` David Rientjes
2015-09-22 5:33 ` Tetsuo Handa
2015-09-22 23:32 ` David Rientjes
2015-09-23 12:03 ` Kyle Walker
2015-09-24 11:50 ` Tetsuo Handa
2015-09-19 14:44 ` Oleg Nesterov
2015-09-21 23:27 ` David Rientjes
2015-09-19 8:25 ` Michal Hocko
2015-09-19 8:22 ` Michal Hocko
2015-09-21 23:08 ` David Rientjes
2015-09-19 15:03 ` can't oom-kill zap the victim's memory? Oleg Nesterov
2015-09-19 15:10 ` Oleg Nesterov
2015-09-19 15:58 ` Michal Hocko
2015-09-20 13:16 ` Oleg Nesterov
2015-09-19 22:24 ` Linus Torvalds
2015-09-19 22:54 ` Raymond Jennings
2015-09-19 23:00 ` Raymond Jennings
2015-09-19 23:13 ` Linus Torvalds
2015-09-20 9:33 ` Michal Hocko
2015-09-20 13:06 ` Oleg Nesterov
2015-09-20 12:56 ` Oleg Nesterov
2015-09-20 18:05 ` Linus Torvalds
2015-09-20 18:21 ` Raymond Jennings
2015-09-20 18:23 ` Raymond Jennings
2015-09-20 19:07 ` Raymond Jennings
2015-09-21 13:57 ` Oleg Nesterov
2015-09-21 13:44 ` Oleg Nesterov
2015-09-21 14:24 ` Michal Hocko
2015-09-21 15:32 ` Oleg Nesterov
2015-09-21 16:12 ` Michal Hocko
2015-09-22 16:06 ` Oleg Nesterov
2015-09-22 23:04 ` David Rientjes
2015-09-23 20:59 ` Michal Hocko
2015-09-24 21:15 ` David Rientjes
2015-09-25 9:35 ` Michal Hocko
2015-09-25 16:14 ` Tetsuo Handa
2015-09-28 16:18 ` Tetsuo Handa
2015-09-28 22:28 ` David Rientjes
2015-10-02 12:36 ` Michal Hocko
2015-10-02 19:01 ` Linus Torvalds
2015-10-05 14:44 ` Michal Hocko
2015-10-07 5:16 ` Vlastimil Babka
2015-10-07 10:43 ` Tetsuo Handa
2015-10-08 9:40 ` Vlastimil Babka
2015-10-06 7:55 ` Eric W. Biederman
2015-10-06 8:49 ` Linus Torvalds
2015-10-06 8:55 ` Linus Torvalds
2015-10-06 14:52 ` Eric W. Biederman
2015-10-03 6:02 ` Can't we use timeout based OOM warning/killing? Tetsuo Handa
2015-10-06 14:51 ` Tetsuo Handa [this message]
2015-10-12 6:43 ` Tetsuo Handa
2015-10-12 15:25 ` Silent hang up caused by pages being not scanned? Tetsuo Handa
2015-10-12 21:23 ` Linus Torvalds
2015-10-13 12:21 ` Tetsuo Handa
2015-10-13 16:37 ` Linus Torvalds
2015-10-14 12:21 ` Tetsuo Handa
2015-10-15 13:14 ` Michal Hocko
2015-10-16 15:57 ` Michal Hocko
2015-10-16 18:34 ` Linus Torvalds
2015-10-16 18:49 ` Tetsuo Handa
2015-10-19 12:57 ` Michal Hocko
2015-10-19 12:53 ` Michal Hocko
2015-10-13 13:32 ` Michal Hocko
2015-10-13 16:19 ` Tetsuo Handa
2015-10-14 13:22 ` Michal Hocko
2015-10-14 14:38 ` Tetsuo Handa
2015-10-14 14:59 ` Michal Hocko
2015-10-14 15:06 ` Tetsuo Handa
2015-10-26 11:44 ` Newbie's question: memory allocation when reclaiming memory Tetsuo Handa
2015-11-05 8:46 ` Vlastimil Babka
2015-10-06 15:25 ` Can't we use timeout based OOM warning/killing? Linus Torvalds
2015-10-08 15:33 ` Tetsuo Handa
2015-10-10 12:50 ` Tetsuo Handa
2015-09-28 22:24 ` can't oom-kill zap the victim's memory? David Rientjes
2015-09-29 7:57 ` Tetsuo Handa
2015-09-29 22:56 ` David Rientjes
2015-09-30 4:25 ` Tetsuo Handa
2015-09-30 10:21 ` Tetsuo Handa
2015-09-30 21:11 ` David Rientjes
2015-10-01 12:13 ` Tetsuo Handa
2015-10-01 14:48 ` Michal Hocko
2015-10-02 13:06 ` Tetsuo Handa
2015-10-06 18:45 ` Oleg Nesterov
2015-10-07 11:03 ` Tetsuo Handa
2015-10-07 12:00 ` Oleg Nesterov
2015-10-08 14:04 ` Michal Hocko
2015-10-08 14:01 ` Michal Hocko
2015-09-21 16:51 ` Tetsuo Handa
2015-09-22 12:43 ` Oleg Nesterov
2015-09-22 14:30 ` Tetsuo Handa
2015-09-22 14:45 ` Oleg Nesterov
2015-09-21 23:42 ` David Rientjes
2015-09-21 16:55 ` Linus Torvalds
2015-09-20 14:50 ` Tetsuo Handa
2015-09-20 14:55 ` Oleg Nesterov
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