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authorPeter Zijlstra <peterz@infradead.org>2014-09-24 10:18:49 +0200
committerIngo Molnar <mingo@kernel.org>2014-10-28 10:55:30 +0100
commit1029a2b52c09e479fd7b07275812ad97868c0fb0 (patch)
tree9fc5eacd5cc76fdcef6238eff08278cd79e253ed /kernel/exit.c
parente22b886a8a43b147e1994a9f970f678fc0df2033 (diff)
downloadlinux-sh-1029a2b52c09e479fd7b07275812ad97868c0fb0.tar.gz
sched, exit: Deal with nested sleeps
do_wait() is a big wait loop, but we set TASK_RUNNING too late; we end up calling potential sleeps before we reset it. Not strictly a bug since we're guaranteed to exit the loop and not call schedule(); put in annotations to quiet might_sleep(). WARNING: CPU: 0 PID: 1 at ../kernel/sched/core.c:7123 __might_sleep+0x7e/0x90() do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8109a788>] do_wait+0x88/0x270 Call Trace: [<ffffffff81694991>] dump_stack+0x4e/0x7a [<ffffffff8109877c>] warn_slowpath_common+0x8c/0xc0 [<ffffffff8109886c>] warn_slowpath_fmt+0x4c/0x50 [<ffffffff810bca6e>] __might_sleep+0x7e/0x90 [<ffffffff811a1c15>] might_fault+0x55/0xb0 [<ffffffff8109a3fb>] wait_consider_task+0x90b/0xc10 [<ffffffff8109a804>] do_wait+0x104/0x270 [<ffffffff8109b837>] SyS_wait4+0x77/0x100 [<ffffffff8169d692>] system_call_fastpath+0x16/0x1b Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: tglx@linutronix.de Cc: umgwanakikbuti@gmail.com Cc: ilya.dryomov@inktank.com Cc: Alex Elder <alex.elder@linaro.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Axel Lin <axel.lin@ingics.com> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Dave Jones <davej@redhat.com> Cc: Guillaume Morin <guillaume@morinfr.org> Cc: Ionut Alexa <ionut.m.alexa@gmail.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Michal Schmidt <mschmidt@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20140924082242.186408915@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/exit.c')
-rw-r--r--kernel/exit.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 5d30019ff953..232c4bc8bcc9 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -997,6 +997,8 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
get_task_struct(p);
read_unlock(&tasklist_lock);
+ sched_annotate_sleep();
+
if ((exit_code & 0x7f) == 0) {
why = CLD_EXITED;
status = exit_code >> 8;
@@ -1079,6 +1081,7 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
* thread can reap it because we its state == DEAD/TRACE.
*/
read_unlock(&tasklist_lock);
+ sched_annotate_sleep();
retval = wo->wo_rusage
? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;
@@ -1210,6 +1213,7 @@ unlock_sig:
pid = task_pid_vnr(p);
why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
read_unlock(&tasklist_lock);
+ sched_annotate_sleep();
if (unlikely(wo->wo_flags & WNOWAIT))
return wait_noreap_copyout(wo, p, pid, uid, why, exit_code);
@@ -1272,6 +1276,7 @@ static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
pid = task_pid_vnr(p);
get_task_struct(p);
read_unlock(&tasklist_lock);
+ sched_annotate_sleep();
if (!wo->wo_info) {
retval = wo->wo_rusage