hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

memcg: avoid deadlock caused by race between oom and cpuset_attach 

mpol_rebind_mm(), which can be called from cpuset_attach(), does
down_write(mm->mmap_sem).  This means down_write(mm->mmap_sem) can be
called under cgroup_mutex.

OTOH, page fault path does down_read(mm->mmap_sem) and calls
mem_cgroup_try_charge_xxx(), which may eventually calls
mem_cgroup_out_of_memory().  And mem_cgroup_out_of_memory() calls
cgroup_lock().  This means cgroup_lock() can be called under
down_read(mm->mmap_sem).

If those two paths race, deadlock can happen.

This patch avoid this deadlock by:
  - remove cgroup_lock() from mem_cgroup_out_of_memory().
  - define new mutex (memcg_tasklist) and serialize mem_cgroup_move_task()
    (->attach handler of memory cgroup) and mem_cgroup_out_of_memory.

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Daisuke Nishimura 2009-01-07 18:08:29 -08:00 committed by Linus Torvalds
parent a5e924f5f8
commit 7f4d454dee
2 changed files with 5 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
mm/memcontrol.c
View File

@ -51,6 +51,7 @@ static int really_do_swap_account __initdata = 1; /* for remember boot option*/
#define do_swap_account (0) #define do_swap_account (0)
#endif #endif
static DEFINE_MUTEX(memcg_tasklist); /* can be hold under cgroup_mutex */
/* /*
* Statistics for memory cgroup. * Statistics for memory cgroup.
@ -827,7 +828,9 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
if (!nr_retries--) { if (!nr_retries--) {
if (oom) { if (oom) {
mutex_lock(&memcg_tasklist);
mem_cgroup_out_of_memory(mem_over_limit, gfp_mask); mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
mutex_unlock(&memcg_tasklist);
mem_over_limit->last_oom_jiffies = jiffies; mem_over_limit->last_oom_jiffies = jiffies;
} }
goto nomem; goto nomem;
@ -2211,10 +2214,12 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
struct cgroup *old_cont, struct cgroup *old_cont,
struct task_struct *p) struct task_struct *p)
{ {
mutex_lock(&memcg_tasklist);
/* /*
* FIXME: It's better to move charges of this process from old * FIXME: It's better to move charges of this process from old
* memcg to new memcg. But it's just on TODO-List now. * memcg to new memcg. But it's just on TODO-List now.
*/ */
mutex_unlock(&memcg_tasklist);
} }
struct cgroup_subsys mem_cgroup_subsys = { struct cgroup_subsys mem_cgroup_subsys = {

2
mm/oom_kill.c
View File

@ -429,7 +429,6 @@ void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask)
unsigned long points = 0; unsigned long points = 0;
struct task_struct *p; struct task_struct *p;
cgroup_lock();
read_lock(&tasklist_lock); read_lock(&tasklist_lock);
retry: retry:
p = select_bad_process(&points, mem); p = select_bad_process(&points, mem);
@ -444,7 +443,6 @@ retry:
goto retry; goto retry;
out: out:
read_unlock(&tasklist_lock); read_unlock(&tasklist_lock);
cgroup_unlock();
} }
#endif #endif