From 5065c7059125e6ddb122535b1fa70af740294d88 Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Thu, 10 Nov 2016 10:46:38 -0800 Subject: [PATCH 1/1] coredump: fix unfreezable coredumping task commit 70d78fe7c8b640b5acfad56ad341985b3810998a upstream. It could be not possible to freeze coredumping task when it waits for 'core_state->startup' completion, because threads are frozen in get_signal() before they got a chance to complete 'core_state->startup'. Inability to freeze a task during suspend will cause suspend to fail. Also CRIU uses cgroup freezer during dump operation. So with an unfreezable task the CRIU dump will fail because it waits for a transition from 'FREEZING' to 'FROZEN' state which will never happen. Use freezer_do_not_count() to tell freezer to ignore coredumping task while it waits for core_state->startup completion. Link: http://lkml.kernel.org/r/1475225434-3753-1-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin Acked-by: Pavel Machek Acked-by: Oleg Nesterov Cc: Alexander Viro Cc: Tejun Heo Cc: "Rafael J. Wysocki" Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: adjust filename, context] Signed-off-by: Ben Hutchings --- fs/exec.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/exec.c b/fs/exec.c index a0006d85785c..3f8d8f331a98 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -1974,8 +1975,11 @@ static int coredump_wait(int exit_code, struct core_state *core_state) complete(vfork_done); } - if (core_waiters) + if (core_waiters > 0) { + freezer_do_not_count(); wait_for_completion(&core_state->startup); + freezer_count(); + } fail: return core_waiters; } -- 2.39.2