We encouter a null ptr problem in our system with the block integrity
feature enabled. The call trace is:
[ 221.903927] ==================================================================
[ 221.904648] BUG: KASAN: null-ptr-deref in bio_integrity_verify_fn+0xbd/0xe3
[ 221.905160] Read of size 8 at addr 0000000000000008 by task kworker/1:1H/135
[ 221.905683]
[ 221.905797] CPU: 1 PID: 135 Comm: kworker/1:1H Not tainted 5.14.0-02729-gb91db6a0b52e-dirty #8
[ 221.906407] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
[ 221.907339] Workqueue: kintegrityd bio_integrity_verify_fn
[ 221.907749] Call Trace:
[ 221.907936] dump_stack_lvl+0x34/0x44
[ 221.908222] kasan_report.cold+0x66/0xdf
[ 221.908511] ? bio_integrity_verify_fn+0xbd/0xe3
[ 221.908865] bio_integrity_verify_fn+0xbd/0xe3
[ 221.909205] process_one_work+0x39f/0x690
[ 221.909515] worker_thread+0x78/0x600
[ 221.909779] ? process_one_work+0x690/0x690
[ 221.910085] kthread+0x1cf/0x200
[ 221.910325] ? set_kthread_struct+0x80/0x80
[ 221.910635] ret_from_fork+0x1f/0x30
[ 221.910902] ==================================================================
[ 221.911426] Disabling lock debugging due to kernel taint
[ 221.911819] BUG: kernel NULL pointer dereference, address: 0000000000000008
[ 221.912323] #PF: supervisor read access in kernel mode
[ 221.912690] #PF: error_code(0x0000) - not-present page
[ 221.913064] PGD 0 P4D 0
[ 221.913263] Oops: 0000 [#1] SMP KASAN
[ 221.913532] CPU: 1 PID: 135 Comm: kworker/1:1H Tainted: G B 5.14.0-02729-gb91db6a0b52e-dirty #8
[ 221.914242] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
[ 221.915222] Workqueue: kintegrityd bio_integrity_verify_fn
[ 221.915636] RIP: 0010:bio_integrity_verify_fn+0xbd/0xe3
[ 221.916024] Code: 2e ff 48 83 7d 00 00 75 0c 48 c7 c7 c0 b9 8b 8f e8 3f ea fd ff 48 89 ef e8 6a fc 2e ff 48 8b 6d 00 48 8d 7d 08 e8 5d fc 2e ff <48> 8b 55 08 48 8d 73 e8 4c 89 e7 e8 bd 10 8c ff 4c 89d
[ 221.917402] RSP: 0018:ffff8881068ffde8 EFLAGS: 00010286
[ 221.917807] RAX: 0000000000000001 RBX: ffff888102d0eb40 RCX: ffffffff8f1bbe22
[ 221.918349] RDX: 1ffffffff3431d80 RSI: 0000000000000246 RDI: ffffffff9a18ec00
[ 221.918872] RBP: 0000000000000000 R08: 0000000000000001 R09: fffffbfff3011121
[ 221.919461] R10: ffffffff98088907 R11: fffffbfff3011120 R12: ffff8881171e7740
[ 221.920132] R13: 0000000000000000 R14: ffff8883d3073000 R15: 0000000000000040
[ 221.920817] FS: 0000000000000000(0000) GS:ffff8883d3040000(0000) knlGS:0000000000000000
[ 221.921601] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 221.922093] CR2: 0000000000000008 CR3: 0000000118df5000 CR4: 00000000000006e0
[ 221.922750] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 221.923431] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 221.924087] Call Trace:
[ 221.924317] process_one_work+0x39f/0x690
[ 221.924710] worker_thread+0x78/0x600
[ 221.925047] ? process_one_work+0x690/0x690
[ 221.925459] kthread+0x1cf/0x200
[ 221.925732] ? set_kthread_struct+0x80/0x80
[ 221.926148] ret_from_fork+0x1f/0x30
[ 221.926514] Modules linked in:
[ 221.926796] CR2: 0000000000000008
[ 221.927225] ---[ end trace 35c0b7896d001c06 ]---
[ 221.927688] RIP: 0010:bio_integrity_verify_fn+0xbd/0xe3
[ 221.928289] Code: 2e ff 48 83 7d 00 00 75 0c 48 c7 c7 c0 b9 8b 8f e8 3f ea fd ff 48 89 ef e8 6a fc 2e ff 48 8b 6d 00 48 8d 7d 08 e8 5d fc 2e ff <48> 8b 55 08 48 8d 73 e8 4c 89 e7 e8 bd 10 8c ff 4c 89d
[ 221.930413] RSP: 0018:ffff8881068ffde8 EFLAGS: 00010286
[ 221.930948] RAX: 0000000000000001 RBX: ffff888102d0eb40 RCX: ffffffff8f1bbe22
[ 221.931628] RDX: 1ffffffff3431d80 RSI: 0000000000000246 RDI: ffffffff9a18ec00
[ 221.932195] RBP: 0000000000000000 R08: 0000000000000001 R09: fffffbfff3011121
[ 221.932739] R10: ffffffff98088907 R11: fffffbfff3011120 R12: ffff8881171e7740
[ 221.933277] R13: 0000000000000000 R14: ffff8883d3073000 R15: 0000000000000040
[ 221.933819] FS: 0000000000000000(0000) GS:ffff8883d3040000(0000) knlGS:0000000000000000
[ 221.934430] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 221.934850] CR2: 0000000000000008 CR3: 0000000118df5000 CR4: 00000000000006e0
[ 221.935391] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 221.935934] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Because the bio verify work is done in the worker thread, someone can
unregister the bio intergity concurrently as below:
CPU0 CPU1
process_one_work nvme_validate_ns
bio_integrity_verify_fn nvme_update_ns_info
nvme_update_disk_info
blk_integrity_unregister
---set queue->integrity as 0
bio_integrity_process
--access bi->profile->veryfy_fn(bi is a pointer of queue->integity)
Before calling blk_integrity_unregister in nvme_update_disk_info, we must
make sure that there is no work item in the kintegrityd_wq. Just call
blk_flush_integrity to flush the work queue so the bug can be resolved.
Signed-off-by: Lihong Kou <koulihong@xxxxxxxxxx>
---
block/blk-core.c | 3 ---
block/blk-integrity.c | 3 +++
drivers/nvme/host/core.c | 3 ++-
3 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 5454db2fa263..62a653e45054 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -389,9 +389,6 @@ void blk_cleanup_queue(struct request_queue *q)
blk_queue_flag_set(QUEUE_FLAG_DEAD, q);
- /* for synchronous bio-based driver finish in-flight integrity i/o */
- blk_flush_integrity();
-
blk_sync_queue(q);
if (queue_is_mq(q))
blk_mq_exit_queue(q);
diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index 69a12177dfb6..94138a2184e3 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -426,6 +426,9 @@ EXPORT_SYMBOL(blk_integrity_register);
*/
void blk_integrity_unregister(struct gendisk *disk)
{
+ /* for synchronous bio-based driver finish in-flight integrity i/o */
+ blk_flush_integrity();
+
blk_queue_flag_clear(QUEUE_FLAG_STABLE_WRITES, disk->queue);
memset(&disk->queue->integrity, 0, sizeof(struct blk_integrity));
}
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 8679a108f571..d937771e456a 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1758,7 +1758,8 @@ static void nvme_update_disk_info(struct gendisk *disk,
bs = (1 << 9);
}
- blk_integrity_unregister(disk);
+ if (blk_get_integrity(disk))
+ blk_integrity_unregister(disk);
atomic_bs = phys_bs = bs;
nvme_setup_streams_ns(ns->ctrl, ns, &phys_bs, &io_opt);
--
2.25.4
