3.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: NeilBrown <[email protected]> commit e0ee778528bbaad28a5c69d2e219269a3a096607 upstream. A 'struct r10bio' has an array of per-copy information at the end. This array is declared with size [0] and r10bio_pool_alloc allocates enough extra space to store the per-copy information depending on the number of copies needed. So declaring a 'struct r10bio on the stack isn't going to work. It won't allocate enough space, and memory corruption will ensue. So in the two places where this is done, declare a sufficiently large structure and use that instead. The two call-sites of this bug were introduced in 3.4 and 3.5 so this is suitable for both those kernels. The patch will have to be modified for 3.4 as it only has one bug. Reported-by: Ivan Vasilyev <[email protected]> Tested-by: Ivan Vasilyev <[email protected]> Signed-off-by: NeilBrown <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/md/raid10.c | 16 ++++++++++------ drivers/md/raid10.h | 2 +- 2 files changed, 11 insertions(+), 7 deletions(-) --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -612,20 +612,24 @@ static int raid10_mergeable_bvec(struct max = biovec->bv_len; if (mddev->merge_check_needed) { - struct r10bio r10_bio; + struct { + struct r10bio r10_bio; + struct r10dev devs[conf->copies]; + } on_stack; + struct r10bio *r10_bio = &on_stack.r10_bio; int s; - r10_bio.sector = sector; - raid10_find_phys(conf, &r10_bio); + r10_bio->sector = sector; + raid10_find_phys(conf, r10_bio); rcu_read_lock(); for (s = 0; s < conf->copies; s++) { - int disk = r10_bio.devs[s].devnum; + int disk = r10_bio->devs[s].devnum; struct md_rdev *rdev = rcu_dereference( conf->mirrors[disk].rdev); if (rdev && !test_bit(Faulty, &rdev->flags)) { struct request_queue *q = bdev_get_queue(rdev->bdev); if (q->merge_bvec_fn) { - bvm->bi_sector = r10_bio.devs[s].addr + bvm->bi_sector = r10_bio->devs[s].addr + rdev->data_offset; bvm->bi_bdev = rdev->bdev; max = min(max, q->merge_bvec_fn( @@ -637,7 +641,7 @@ static int raid10_mergeable_bvec(struct struct request_queue *q = bdev_get_queue(rdev->bdev); if (q->merge_bvec_fn) { - bvm->bi_sector = r10_bio.devs[s].addr + bvm->bi_sector = r10_bio->devs[s].addr + rdev->data_offset; bvm->bi_bdev = rdev->bdev; max = min(max, q->merge_bvec_fn( --- a/drivers/md/raid10.h +++ b/drivers/md/raid10.h @@ -104,7 +104,7 @@ struct r10bio { * We choose the number when they are allocated. * We sometimes need an extra bio to write to the replacement. */ - struct { + struct r10dev { struct bio *bio; union { struct bio *repl_bio; /* used for resync and -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
