Messages in this thread Patch in this message | | | Date | Fri, 30 Jul 2010 10:30:31 -0700 | From | Greg KH <> | Subject | [066/140] md: raid10: Fix null pointer dereference in fix_read_error() |
| |
2.6.33-stable review patch. If anyone has any objections, please let us know.
------------------
From: Prasanna S. Panchamukhi <prasanna.panchamukhi@riverbed.com>
commit 0544a21db02c1d8883158fd6f323364f830a120a upstream.
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().
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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/md/raid10.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
--- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1486,14 +1486,14 @@ static void fix_read_error(conf_t *conf, 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)) { @@ -1533,7 +1533,7 @@ static void fix_read_error(conf_t *conf, 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)) { @@ -1567,7 +1567,7 @@ static void fix_read_error(conf_t *conf, rcu_read_lock(); while (sl != r10_bio->read_slot) { char b[BDEVNAME_SIZE]; - int d; + if (sl==0) sl = conf->copies; sl--; @@ -1603,7 +1603,7 @@ static void fix_read_error(conf_t *conf, } sl = start; while (sl != r10_bio->read_slot) { - int d; + if (sl==0) sl = conf->copies; sl--;
| |