diff options
| author | David Rientjes <rientjes@google.com> | 2015-11-05 18:48:05 -0800 |
|---|---|---|
| committer | Moyster <oysterized@gmail.com> | 2019-07-08 14:08:55 +0200 |
| commit | 173048a77ade2e0a276ba52ebf5e9ead5f4091d3 (patch) | |
| tree | 2b5fc3e96a25133ec716eba4c5361c0be31eb608 /mm/oom_kill.c | |
| parent | 3feac374ea522799fa5470b4f6d8d577b5490974 (diff) | |
mm, oom: remove task_lock protecting comm printing
The oom killer takes task_lock() in a couple of places solely to protect
printing the task's comm.
A process's comm, including current's comm, may change due to
/proc/pid/comm or PR_SET_NAME.
The comm will always be NULL-terminated, so the worst race scenario would
only be during update. We can tolerate a comm being printed that is in
the middle of an update to avoid taking the lock.
Other locations in the kernel have already dropped task_lock() when
printing comm, so this is consistent.
Change-Id: I89f64666a1db5d414aa53862fd6b665bbb8125bc
Signed-off-by: David Rientjes <rientjes@google.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/oom_kill.c')
| -rw-r--r-- | mm/oom_kill.c | 8 |
1 files changed, 1 insertions, 7 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 4b7e9037d..5933c3c15 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -399,13 +399,11 @@ void dump_tasks(const struct mem_cgroup *memcg, const nodemask_t *nodemask) static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order, struct mem_cgroup *memcg, const nodemask_t *nodemask) { - task_lock(current); pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, " "oom_score_adj=%hd\n", current->comm, gfp_mask, order, current->signal->oom_score_adj); - cpuset_print_task_mems_allowed(current); - task_unlock(current); + cpuset_print_current_mems_allowed(); dump_stack(); if (memcg) mem_cgroup_print_oom_info(memcg, p); @@ -533,10 +531,8 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, if (__ratelimit(&oom_rs)) dump_header(p, gfp_mask, order, memcg, nodemask); - task_lock(p); pr_err("%s: Kill process %d (%s) score %u or sacrifice child\n", message, task_pid_nr(p), p->comm, points); - task_unlock(p); /* * If any of p's children has a different mm and is eligible for kill, @@ -629,10 +625,8 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, if (fatal_signal_pending(p)) continue; - task_lock(p); /* Protect ->comm from prctl() */ pr_info("Kill process %d (%s) sharing same memory\n", task_pid_nr(p), p->comm); - task_unlock(p); do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true); } rcu_read_unlock(); |