From: Andrey Ryabinin <[email protected]> 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/[email protected] Signed-off-by: Andrey Ryabinin <[email protected]> Acked-by: Pavel Machek <[email protected]> Acked-by: Oleg Nesterov <[email protected]> Cc: Alexander Viro <[email protected]> Cc: Tejun Heo <[email protected]> Cc: "Rafael J. Wysocki" <[email protected]> Cc: Michal Hocko <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Willy Tarreau <[email protected]> --- fs/coredump.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/coredump.c b/fs/coredump.c index 4f03b2b..a94f94d 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -1,6 +1,7 @@ #include <linux/slab.h> #include <linux/file.h> #include <linux/fdtable.h> +#include <linux/freezer.h> #include <linux/mm.h> #include <linux/stat.h> #include <linux/fcntl.h> @@ -375,7 +376,9 @@ 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 -- 2.8.0.rc2.1.gbe9624a
