Re: [PATCH v2 1/4] md/raid10: fix null-ptr-deref of mreplace in raid10_sync_request
From: Yu Kuai <hidden>
Date: 2023-05-27 01:21:38
Also in:
lkml
Hi, 在 2023/05/26 15:45, linan666@huaweicloud.com 写道:
From: Li Nan <redacted>
need_replace will be set to 1 if no-Faulty mreplace exists, and mreplace
will be deref later. However, the latter check of mreplace might set
mreplace to NULL, null-ptr-deref occurs if need_replace is 1 at this time.
Fix it by merging two checks into one. And replace 'need_replace' with
'mreplace' because their values are always the same.
Fixes: ee37d7314a32 ("md/raid10: Fix raid10 replace hang when new added disk faulty")
Signed-off-by: Li Nan <redacted>Other than some nits below, this patch looks good to me, feel free too add: Reviewed-by: Yu Kuai <redacted>
quoted hunk ↗ jump to hunk
--- drivers/md/raid10.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-)diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 4fcfcb350d2b..e21502c03b45 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c@@ -3438,7 +3438,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr, int must_sync; int any_working; int need_recover = 0; - int need_replace = 0; struct raid10_info *mirror = &conf->mirrors[i]; struct md_rdev *mrdev, *mreplace;@@ -3451,10 +3450,10 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr, !test_bit(In_sync, &mrdev->flags)) need_recover = 1; if (mreplace != NULL && - !test_bit(Faulty, &mreplace->flags)) - need_replace = 1; + test_bit(Faulty, &mreplace->flags))
This can be keeped in one line.
quoted hunk ↗ jump to hunk
+ mreplace = NULL; - if (!need_recover && !need_replace) { + if (!need_recover && !mreplace) { rcu_read_unlock(); continue; }@@ -3470,8 +3469,6 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr, rcu_read_unlock(); continue; } - if (mreplace && test_bit(Faulty, &mreplace->flags)) - mreplace = NULL; /* Unless we are doing a full sync, or a replacement * we only need to recover the block if it is set in * the bitmap@@ -3594,11 +3591,11 @@ static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr, bio = r10_bio->devs[1].repl_bio; if (bio) bio->bi_end_io = NULL; - /* Note: if need_replace, then bio + /* Note: if replace is not NULL, then bio * cannot be NULL as r10buf_pool_alloc will * have allocated it. */ - if (!need_replace) + if (!mreplace) break; bio->bi_next = biolist; biolist = bio;