| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.18 04/68] md:raid1: fix a dead loop when read from a WriteMostly disk | Date | Fri, 5 May 2017 11:31:49 -0700 |
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3.18-stable review patch. If anyone has any objections, please let me know.
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From: Wei Fang <fangwei1@huawei.com>
commit 816b0acf3deb6d6be5d0519b286fdd4bafade905 upstream.
If first_bad == this_sector when we get the WriteMostly disk in read_balance(), valid disk will be returned with zero max_sectors. It'll lead to a dead loop in make_request(), and OOM will happen because of endless allocation of struct bio.
Since we can't get data from this disk in this case, so continue for another disk.
Signed-off-by: Wei Fang <fangwei1@huawei.com> Signed-off-by: Shaohua Li <shli@fb.com> Cc: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/md/raid1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -563,7 +563,7 @@ static int read_balance(struct r1conf *c if (best_dist_disk < 0) { if (is_badblock(rdev, this_sector, sectors, &first_bad, &bad_sectors)) { - if (first_bad < this_sector) + if (first_bad <= this_sector) /* Cannot use this */ continue; best_good_sectors = first_bad - this_sector;
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