Wu Fengguang 977b7e3a52 writeback: fix dereferencing NULL bdi->dev on trace_writeback_queue ...

When a SD card is hot removed without umount, del_gendisk() will call
bdi_unregister() without destroying/freeing it. This leaves the bdi in
the bdi->dev = NULL, bdi->wb.task = NULL, bdi->bdi_list removed state.

When sync(2) gets the bdi before bdi_unregister() and calls
bdi_queue_work() after the unregister, trace_writeback_queue will be
dereferencing the NULL bdi->dev. Fix it with a simple test for NULL.

LKML-reference: http://lkml.org/lkml/2012/1/18/346
Cc: stable@kernel.org
Reported-by: Rabin Vincent <rabin@rab.in>
Tested-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>

2012-02-06 11:17:25 +08:00

..

events

writeback: fix dereferencing NULL bdi->dev on trace_writeback_queue

2012-02-06 11:17:25 +08:00

define_trace.h

Revert "tracing: Include module.h in define_trace.h"

2011-10-31 19:32:35 -04:00

ftrace.h

perf: Fix counter of ftrace events

2011-10-04 11:07:54 +02:00

syscall.h

tracing: Use a global field list for all syscall exit events

2010-06-28 17:12:44 -04:00