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| author | Prasanna S. Panchamukhi <prasanna.panchamukhi@riverbed.com> | 2010-06-24 13:31:03 +1000 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2010-06-24 13:31:03 +1000 |
| commit | 0544a21db02c1d8883158fd6f323364f830a120a (patch) | |
| tree | 086c38e3c9132a8ecdee0ccbdd845ce2604caad9 /drivers/md | |
| parent | f3b99be19ded511a1bf05a148276239d9f13eefa (diff) | |
| download | linux-0544a21db02c1d8883158fd6f323364f830a120a.tar.gz linux-0544a21db02c1d8883158fd6f323364f830a120a.tar.bz2 linux-0544a21db02c1d8883158fd6f323364f830a120a.zip | |
md: raid10: Fix null pointer dereference in fix_read_error()
Such NULL pointer dereference can occur when the driver was fixing the
read errors/bad blocks and the disk was physically removed
causing a system crash. This patch check if the
rcu_dereference() returns valid rdev before accessing it in fix_read_error().
Cc: stable@kernel.org
Signed-off-by: Prasanna S. Panchamukhi <prasanna.panchamukhi@riverbed.com>
Signed-off-by: Rob Becker <rbecker@riverbed.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/raid10.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 03724992cdf2..6d420cb487b5 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1482,14 +1482,14 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio) int sectors = r10_bio->sectors; mdk_rdev_t*rdev; int max_read_errors = atomic_read(&mddev->max_corr_read_errors); + int d = r10_bio->devs[r10_bio->read_slot].devnum; rcu_read_lock(); - { - int d = r10_bio->devs[r10_bio->read_slot].devnum; + rdev = rcu_dereference(conf->mirrors[d].rdev); + if (rdev) { /* If rdev is not NULL */ char b[BDEVNAME_SIZE]; int cur_read_error_count = 0; - rdev = rcu_dereference(conf->mirrors[d].rdev); bdevname(rdev->bdev, b); if (test_bit(Faulty, &rdev->flags)) { @@ -1530,7 +1530,7 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio) rcu_read_lock(); do { - int d = r10_bio->devs[sl].devnum; + d = r10_bio->devs[sl].devnum; rdev = rcu_dereference(conf->mirrors[d].rdev); if (rdev && test_bit(In_sync, &rdev->flags)) { @@ -1564,7 +1564,7 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio) rcu_read_lock(); while (sl != r10_bio->read_slot) { char b[BDEVNAME_SIZE]; - int d; + if (sl==0) sl = conf->copies; sl--; @@ -1601,7 +1601,7 @@ static void fix_read_error(conf_t *conf, mddev_t *mddev, r10bio_t *r10_bio) } sl = start; while (sl != r10_bio->read_slot) { - int d; + if (sl==0) sl = conf->copies; sl--; |