From bf0972039ddc483a9cb79edae73076c635876568 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 3 Apr 2014 14:46:23 -0700 Subject: bdi: avoid oops on device removal commit 5acda9d12dcf1ad0d9a5a2a7c646de3472fa7555 upstream. After commit 839a8e8660b6 ("writeback: replace custom worker pool implementation with unbound workqueue") when device is removed while we are writing to it we crash in bdi_writeback_workfn() -> set_worker_desc() because bdi->dev is NULL. This can happen because even though bdi_unregister() cancels all pending flushing work, nothing really prevents new ones from being queued from balance_dirty_pages() or other places. Fix the problem by clearing BDI_registered bit in bdi_unregister() and checking it before scheduling of any flushing work. Fixes: 839a8e8660b6777e7fe4e80af1a048aebe2b5977 Reviewed-by: Tejun Heo Signed-off-by: Jan Kara Cc: Derek Basehore Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- include/linux/backing-dev.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index c3881553f7d1..4cfdbf28fc6a 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -95,7 +95,7 @@ struct backing_dev_info { unsigned int max_ratio, max_prop_frac; struct bdi_writeback wb; /* default writeback info for this bdi */ - spinlock_t wb_lock; /* protects work_list */ + spinlock_t wb_lock; /* protects work_list & wb.dwork scheduling */ struct list_head work_list; -- cgit v1.2.3