From e835220ed25f6bd1e62fb51e351f5ccc9a157554 Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Thu, 10 Nov 2016 10:46:38 -0800 Subject: 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 Signed-off-by: Greg Kroah-Hartman --- fs/coredump.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs') diff --git a/fs/coredump.c b/fs/coredump.c index dfc87c5f5a54..5d15c4975ba1 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -1,6 +1,7 @@ #include #include #include +#include #include #include #include @@ -399,7 +400,9 @@ static int coredump_wait(int exit_code, struct core_state *core_state) if (core_waiters > 0) { struct core_thread *ptr; + freezer_do_not_count(); wait_for_completion(&core_state->startup); + freezer_count(); /* * Wait for all the threads to become inactive, so that * all the thread context (extended register state, like -- cgit v1.2.3