6.8-stable review patch. If anyone has any objections, please let me know.
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From: Yu Kuai yukuai3@huawei.com
commit fcf3f7e2fc8a53a6140beee46ec782a4c88e4744 upstream.
r1_bio->bios[] is used to record new bios that will be issued to underlying disks, however, in raid1_write_request(), r1_bio->bios[] will set to the original bio temporarily. Meanwhile, if blocked rdev is set, free_r1bio() will be called causing that all r1_bio->bios[] to be freed:
raid1_write_request() r1_bio = alloc_r1bio(mddev, bio); -> r1_bio->bios[] is NULL for (i = 0; i < disks; i++) -> for each rdev in conf // first rdev is normal r1_bio->bios[0] = bio; -> set to original bio // second rdev is blocked if (test_bit(Blocked, &rdev->flags)) break
if (blocked_rdev) free_r1bio() put_all_bios() bio_put(r1_bio->bios[0]) -> original bio is freed
Test scripts:
mdadm -CR /dev/md0 -l1 -n4 /dev/sd[abcd] --assume-clean fio -filename=/dev/md0 -ioengine=libaio -rw=write -bs=4k -numjobs=1 \ -iodepth=128 -name=test -direct=1 echo blocked > /sys/block/md0/md/rd2/state
Test result:
BUG bio-264 (Not tainted): Object already free -----------------------------------------------------------------------------
Allocated in mempool_alloc_slab+0x24/0x50 age=1 cpu=1 pid=869 kmem_cache_alloc+0x324/0x480 mempool_alloc_slab+0x24/0x50 mempool_alloc+0x6e/0x220 bio_alloc_bioset+0x1af/0x4d0 blkdev_direct_IO+0x164/0x8a0 blkdev_write_iter+0x309/0x440 aio_write+0x139/0x2f0 io_submit_one+0x5ca/0xb70 __do_sys_io_submit+0x86/0x270 __x64_sys_io_submit+0x22/0x30 do_syscall_64+0xb1/0x210 entry_SYSCALL_64_after_hwframe+0x6c/0x74 Freed in mempool_free_slab+0x1f/0x30 age=1 cpu=1 pid=869 kmem_cache_free+0x28c/0x550 mempool_free_slab+0x1f/0x30 mempool_free+0x40/0x100 bio_free+0x59/0x80 bio_put+0xf0/0x220 free_r1bio+0x74/0xb0 raid1_make_request+0xadf/0x1150 md_handle_request+0xc7/0x3b0 md_submit_bio+0x76/0x130 __submit_bio+0xd8/0x1d0 submit_bio_noacct_nocheck+0x1eb/0x5c0 submit_bio_noacct+0x169/0xd40 submit_bio+0xee/0x1d0 blkdev_direct_IO+0x322/0x8a0 blkdev_write_iter+0x309/0x440 aio_write+0x139/0x2f0
Since that bios for underlying disks are not allocated yet, fix this problem by using mempool_free() directly to free the r1_bio.
Fixes: 992db13a4aee ("md/raid1: free the r1bio before waiting for blocked rdev") Cc: stable@vger.kernel.org # v6.6+ Reported-by: Coly Li colyli@suse.de Signed-off-by: Yu Kuai yukuai3@huawei.com Tested-by: Coly Li colyli@suse.de Signed-off-by: Song Liu song@kernel.org Link: https://lore.kernel.org/r/20240308093726.1047420-1-yukuai1@huaweicloud.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/raid1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1474,7 +1474,7 @@ static void raid1_write_request(struct m for (j = 0; j < i; j++) if (r1_bio->bios[j]) rdev_dec_pending(conf->mirrors[j].rdev, mddev); - free_r1bio(r1_bio); + mempool_free(r1_bio, &conf->r1bio_pool); allow_barrier(conf, bio->bi_iter.bi_sector);
if (bio->bi_opf & REQ_NOWAIT) {