The patch titled
select_bad_process(): kill a bogus PF_DEAD/TASK_DEAD check
has been added to the -mm tree. Its filename is
select_bad_process-kill-a-bogus-pf_dead-task_dead-check.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: select_bad_process(): kill a bogus PF_DEAD/TASK_DEAD check
From: Oleg Nesterov <oleg@xxxxxxxxxx>
The only one usage of TASK_DEAD outside of last schedule path,
select_bad_process:
for_each_task(p) {
if (!p->mm)
continue;
...
if (p->state == TASK_DEAD)
continue;
...
TASK_DEAD state is set at the end of do_exit(), this means that p->mm
was already set == NULL by exit_mm(), so this task was already rejected
by 'if (!p->mm)' above.
Note also that the caller holds tasklist_lock, this means that p can't
pass exit_notify() and then set TASK_DEAD when p->mm != NULL.
Also, remove open-coded is_init().
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
mm/oom_kill.c | 12 ++++++------
1 files changed, 6 insertions(+), 6 deletions(-)
diff -puN mm/oom_kill.c~select_bad_process-kill-a-bogus-pf_dead-task_dead-check mm/oom_kill.c
--- a/mm/oom_kill.c~select_bad_process-kill-a-bogus-pf_dead-task_dead-check
+++ a/mm/oom_kill.c
@@ -207,11 +207,14 @@ static struct task_struct *select_bad_pr
unsigned long points;
int releasing;
- /* skip kernel threads */
+ /*
+ * skip kernel threads and tasks which have already released
+ * their mm.
+ */
if (!p->mm)
continue;
- /* skip the init task with pid == 1 */
- if (p->pid == 1)
+ /* skip the init task */
+ if (is_init(p))
continue;
/*
@@ -227,9 +230,6 @@ static struct task_struct *select_bad_pr
releasing = test_tsk_thread_flag(p, TIF_MEMDIE) ||
p->flags & PF_EXITING;
if (releasing) {
- /* TASK_DEAD tasks have already released their mm */
- if (p->state == TASK_DEAD)
- continue;
if (p->flags & PF_EXITING && p == current) {
chosen = p;
*ppoints = ULONG_MAX;
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
pid-implement-transfer_pid-and-use-it-to-simplify-de_thread.patch
pid-remove-temporary-debug-code-in-attach_pid.patch
rtmutex-clean-up-and-remove-some-extra-spinlocks.patch
rtmutex-clean-up-and-remove-some-extra-spinlocks-more.patch
elf_core_dump-dont-take-tasklist_lock.patch
elf_fdpic_core_dump-dont-take-tasklist_lock.patch
has_stopped_jobs-cleanup.patch
__dequeue_signal-cleanup.patch
do_sched_setscheduler-dont-take-tasklist_lock.patch
introduce-is_rt_policy-helper.patch
sched_setscheduler-fix-policy-checks.patch
reparent_to_init-use-has_rt_policy.patch
copy_process-cosmetic-ioprio-tweak.patch
futex_find_get_task-dont-take-tasklist_lock.patch
sys_get_robust_list-dont-take-tasklist_lock.patch
set-exit_dead-state-in-do_exit-not-in-schedule.patch
kill-pf_dead-flag.patch
introduce-task_dead-state.patch
select_bad_process-kill-a-bogus-pf_dead-task_dead-check.patch
simplify-pid-iterators.patch
pidhash-temporary-debug-checks.patch
-
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