33 lines
1.3 KiB
Diff
33 lines
1.3 KiB
Diff
From: Stefan Bader <stefan.bader@canonical.com>
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Date: Sun, 29 Nov 2015 18:44:49 -0800
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Subject: [7/8] bcache: prevent crash on changing writeback_running
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Origin: https://git.kernel.org/cgit/linux/kernel/git/axboe/linux-block.git/commit?id=8d16ce540c94c9d366eb36fc91b7154d92d6397b
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Added a safeguard in the shutdown case. At least while not being
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attached it is also possible to trigger a kernel bug by writing into
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writeback_running. This change adds the same check before trying to
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wake up the thread for that case.
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Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
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Cc: Kent Overstreet <kent.overstreet@gmail.com>
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Cc: stable@vger.kernel.org
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Signed-off-by: Jens Axboe <axboe@fb.com>
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---
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drivers/md/bcache/writeback.h | 3 ++-
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1 file changed, 2 insertions(+), 1 deletion(-)
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diff --git a/drivers/md/bcache/writeback.h b/drivers/md/bcache/writeback.h
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index 0a9dab1..073a042 100644
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--- a/drivers/md/bcache/writeback.h
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+++ b/drivers/md/bcache/writeback.h
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@@ -63,7 +63,8 @@ static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
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static inline void bch_writeback_queue(struct cached_dev *dc)
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{
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- wake_up_process(dc->writeback_thread);
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+ if (!IS_ERR_OR_NULL(dc->writeback_thread))
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+ wake_up_process(dc->writeback_thread);
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}
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static inline void bch_writeback_add(struct cached_dev *dc)
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