From: Tasos Sahanidis tasos@tasossah.com
[ Upstream commit fb48febce7e30baed94dd791e19521abd2c3fd83 ]
When the watchdog detects a disk change, it calls cancel_activity(), which in turn tries to cancel the fd_timer delayed work.
In the above scenario, fd_timer_fn is set to fd_watchdog(), meaning it is trying to cancel its own work. This results in a hang as cancel_delayed_work_sync() is waiting for the watchdog (itself) to return, which never happens.
This can be reproduced relatively consistently by attempting to read a broken floppy, and ejecting it while IO is being attempted and retried.
To resolve this, this patch calls cancel_delayed_work() instead, which cancels the work without waiting for the watchdog to return and finish.
Before this regression was introduced, the code in this section used del_timer(), and not del_timer_sync() to delete the watchdog timer.
Link: https://lore.kernel.org/r/399e486c-6540-db27-76aa-7a271b061f76@tasossah.com Fixes: 070ad7e793dc ("floppy: convert to delayed work and single-thread wq") Signed-off-by: Tasos Sahanidis tasos@tasossah.com Signed-off-by: Denis Efremov efremov@linux.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/floppy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 40c251ef175db..826ab5f2f6b9f 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -994,7 +994,7 @@ static DECLARE_DELAYED_WORK(fd_timer, fd_timer_workfn); static void cancel_activity(void) { do_floppy = NULL; - cancel_delayed_work_sync(&fd_timer); + cancel_delayed_work(&fd_timer); cancel_work_sync(&floppy_work); }