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authorPrasanna S. Panchamukhi <prasanna.panchamukhi@riverbed.com>2010-06-24 13:31:03 +1000
committerNeilBrown <neilb@suse.de>2010-06-24 13:31:03 +1000
commit0544a21db02c1d8883158fd6f323364f830a120a (patch)
tree086c38e3c9132a8ecdee0ccbdd845ce2604caad9 /drivers/md
parentf3b99be19ded511a1bf05a148276239d9f13eefa (diff)
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.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 03724992cdf..6d420cb487b 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--;