6.6-stable review patch. If anyone has any objections, please let me know.
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From: Mikulas Patocka mpatocka@redhat.com
commit 28f07f2ab4b3a2714f1fefcc58ada4bcc195f806 upstream.
The commit 5721d4e5a9cd enhanced dm-verity, so that it can verify blocks from tasklets rather than from workqueues. This reportedly improves performance significantly.
However, dm-verity was using the flag CRYPTO_TFM_REQ_MAY_SLEEP from tasklets which resulted in warnings about sleeping function being called from non-sleeping context.
BUG: sleeping function called from invalid context at crypto/internal.h:206 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 14, name: ksoftirqd/0 preempt_count: 100, expected: 0 RCU nest depth: 0, expected: 0 CPU: 0 PID: 14 Comm: ksoftirqd/0 Tainted: G W 6.7.0-rc1 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x32/0x50 __might_resched+0x110/0x160 crypto_hash_walk_done+0x54/0xb0 shash_ahash_update+0x51/0x60 verity_hash_update.isra.0+0x4a/0x130 [dm_verity] verity_verify_io+0x165/0x550 [dm_verity] ? free_unref_page+0xdf/0x170 ? psi_group_change+0x113/0x390 verity_tasklet+0xd/0x70 [dm_verity] tasklet_action_common.isra.0+0xb3/0xc0 __do_softirq+0xaf/0x1ec ? smpboot_thread_fn+0x1d/0x200 ? sort_range+0x20/0x20 run_ksoftirqd+0x15/0x30 smpboot_thread_fn+0xed/0x200 kthread+0xdc/0x110 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x28/0x40 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork_asm+0x11/0x20 </TASK>
This commit fixes dm-verity so that it doesn't use the flags CRYPTO_TFM_REQ_MAY_SLEEP and CRYPTO_TFM_REQ_MAY_BACKLOG from tasklets. The crypto API would do GFP_ATOMIC allocation instead, it could return -ENOMEM and we catch -ENOMEM in verity_tasklet and requeue the request to the workqueue.
Signed-off-by: Mikulas Patocka mpatocka@redhat.com Cc: stable@vger.kernel.org # v6.0+ Fixes: 5721d4e5a9cd ("dm verity: Add optional "try_verify_in_tasklet" feature") Signed-off-by: Mike Snitzer snitzer@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/dm-verity-fec.c | 4 ++-- drivers/md/dm-verity-target.c | 23 ++++++++++++----------- drivers/md/dm-verity.h | 2 +- 3 files changed, 15 insertions(+), 14 deletions(-)
--- a/drivers/md/dm-verity-fec.c +++ b/drivers/md/dm-verity-fec.c @@ -185,7 +185,7 @@ static int fec_is_erasure(struct dm_veri { if (unlikely(verity_hash(v, verity_io_hash_req(v, io), data, 1 << v->data_dev_block_bits, - verity_io_real_digest(v, io)))) + verity_io_real_digest(v, io), true))) return 0;
return memcmp(verity_io_real_digest(v, io), want_digest, @@ -386,7 +386,7 @@ static int fec_decode_rsb(struct dm_veri /* Always re-validate the corrected block against the expected hash */ r = verity_hash(v, verity_io_hash_req(v, io), fio->output, 1 << v->data_dev_block_bits, - verity_io_real_digest(v, io)); + verity_io_real_digest(v, io), true); if (unlikely(r < 0)) return r;
--- a/drivers/md/dm-verity-target.c +++ b/drivers/md/dm-verity-target.c @@ -135,20 +135,21 @@ static int verity_hash_update(struct dm_ * Wrapper for crypto_ahash_init, which handles verity salting. */ static int verity_hash_init(struct dm_verity *v, struct ahash_request *req, - struct crypto_wait *wait) + struct crypto_wait *wait, bool may_sleep) { int r;
ahash_request_set_tfm(req, v->tfm); - ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP | - CRYPTO_TFM_REQ_MAY_BACKLOG, - crypto_req_done, (void *)wait); + ahash_request_set_callback(req, + may_sleep ? CRYPTO_TFM_REQ_MAY_SLEEP | CRYPTO_TFM_REQ_MAY_BACKLOG : 0, + crypto_req_done, (void *)wait); crypto_init_wait(wait);
r = crypto_wait_req(crypto_ahash_init(req), wait);
if (unlikely(r < 0)) { - DMERR("crypto_ahash_init failed: %d", r); + if (r != -ENOMEM) + DMERR("crypto_ahash_init failed: %d", r); return r; }
@@ -179,12 +180,12 @@ out: }
int verity_hash(struct dm_verity *v, struct ahash_request *req, - const u8 *data, size_t len, u8 *digest) + const u8 *data, size_t len, u8 *digest, bool may_sleep) { int r; struct crypto_wait wait;
- r = verity_hash_init(v, req, &wait); + r = verity_hash_init(v, req, &wait, may_sleep); if (unlikely(r < 0)) goto out;
@@ -322,7 +323,7 @@ static int verity_verify_level(struct dm
r = verity_hash(v, verity_io_hash_req(v, io), data, 1 << v->hash_dev_block_bits, - verity_io_real_digest(v, io)); + verity_io_real_digest(v, io), !io->in_tasklet); if (unlikely(r < 0)) goto release_ret_r;
@@ -556,7 +557,7 @@ static int verity_verify_io(struct dm_ve continue; }
- r = verity_hash_init(v, req, &wait); + r = verity_hash_init(v, req, &wait, !io->in_tasklet); if (unlikely(r < 0)) return r;
@@ -652,7 +653,7 @@ static void verity_tasklet(unsigned long
io->in_tasklet = true; err = verity_verify_io(io); - if (err == -EAGAIN) { + if (err == -EAGAIN || err == -ENOMEM) { /* fallback to retrying with work-queue */ INIT_WORK(&io->work, verity_work); queue_work(io->v->verify_wq, &io->work); @@ -1033,7 +1034,7 @@ static int verity_alloc_zero_digest(stru goto out;
r = verity_hash(v, req, zero_data, 1 << v->data_dev_block_bits, - v->zero_digest); + v->zero_digest, true);
out: kfree(req); --- a/drivers/md/dm-verity.h +++ b/drivers/md/dm-verity.h @@ -128,7 +128,7 @@ extern int verity_for_bv_block(struct dm u8 *data, size_t len));
extern int verity_hash(struct dm_verity *v, struct ahash_request *req, - const u8 *data, size_t len, u8 *digest); + const u8 *data, size_t len, u8 *digest, bool may_sleep);
extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io, sector_t block, u8 *digest, bool *is_zero);