The patch titled
revert "Drop tasklist lock in do_sched_setscheduler"
has been added to the -mm tree. Its filename is
for-2618-revert-drop-tasklist-lock-in-do_sched_setscheduler.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: revert "Drop tasklist lock in do_sched_setscheduler"
From: Oleg Nesterov <oleg@xxxxxxxxxx>
sched_setscheduler() looks at ->signal->rlim[]. It is unsafe do
dereference ->signal unless tasklist_lock or ->siglock is held (or p ==
current). We pin the task structure, but this can't prevent from
release_task()->__exit_signal() which sets ->signal = NULL.
Restore tasklist_lock across the setscheduler call.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/sched.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff -puN kernel/sched.c~for-2618-revert-drop-tasklist-lock-in-do_sched_setscheduler kernel/sched.c
--- a/kernel/sched.c~for-2618-revert-drop-tasklist-lock-in-do_sched_setscheduler
+++ a/kernel/sched.c
@@ -4162,10 +4162,8 @@ do_sched_setscheduler(pid_t pid, int pol
read_unlock_irq(&tasklist_lock);
return -ESRCH;
}
- get_task_struct(p);
- read_unlock_irq(&tasklist_lock);
retval = sched_setscheduler(p, policy, &lparam);
- put_task_struct(p);
+ read_unlock_irq(&tasklist_lock);
return retval;
}
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
sys_getppid-oopses-on-debug-kernel-v2.patch
for-2618-revert-drop-tasklist-lock-in-do_sched_setscheduler.patch
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
simplify-pid-iterators.patch
pidhash-temporary-debug-checks.patch
-
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