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| author |  Ahmed S. Darwish <a.darwish@linutronix.de>
| 2020-06-03 16:49:48 +0200 |
|---|---|---|
| committer |  Jens Axboe <axboe@kernel.dk>
| 2020-06-04 21:22:28 -0600 |
| commit | 15b81ce5abdc4b502aa31dff2d415b79d2349d2f (patch) | |
| tree | 33b5c887643b18efec05f05d65749d0e79af59ac /kernel | |
| parent | block: remove the error argument to the block_bio_complete tracepoint (diff) | |
| download | linux-15b81ce5abdc4b502aa31dff2d415b79d2349d2f.tar.gz linux-15b81ce5abdc4b502aa31dff2d415b79d2349d2f.tar.bz2 linux-15b81ce5abdc4b502aa31dff2d415b79d2349d2f.zip | |
block: nr_sects_write(): Disable preemption on seqcount write
For optimized block readers not holding a mutex, the "number of sectors"
64-bit value is protected from tearing on 32-bit architectures by a
sequence counter.
Disable preemption before entering that sequence counter's write side
critical section. Otherwise, the read side can preempt the write side
section and spin for the entire scheduler tick. If the reader belongs to
a real-time scheduling class, it can spin forever and the kernel will
livelock.
Fixes: c83f6bf98dc1 ("block: add partition resize function to blkpg ioctl")
Cc: <stable@vger.kernel.org>
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'kernel')
0 files changed, 0 insertions, 0 deletions