From: Ignat Korchagin <ig...@cloudflare.com> commit d68b29584c25dbacd01ed44a3e45abb35353f1de upstream.
Commit 39d42fa96ba1 ("dm crypt: add flags to optionally bypass kcryptd workqueues") made it possible for some code paths in dm-crypt to be executed in softirq context, when the underlying driver processes IO requests in interrupt/softirq context. In this case sometimes when allocating a new crypto request we may get a stacktrace like below: [ 210.103008][ C0] BUG: sleeping function called from invalid context at mm/mempool.c:381 [ 210.104746][ C0] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2602, name: fio [ 210.106599][ C0] CPU: 0 PID: 2602 Comm: fio Tainted: G W 5.10.0+ #50 [ 210.108331][ C0] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 [ 210.110212][ C0] Call Trace: [ 210.110921][ C0] <IRQ> [ 210.111527][ C0] dump_stack+0x7d/0xa3 [ 210.112411][ C0] ___might_sleep.cold+0x122/0x151 [ 210.113527][ C0] mempool_alloc+0x16b/0x2f0 [ 210.114524][ C0] ? __queue_work+0x515/0xde0 [ 210.115553][ C0] ? mempool_resize+0x700/0x700 [ 210.116586][ C0] ? crypt_endio+0x91/0x180 [ 210.117479][ C0] ? blk_update_request+0x757/0x1150 [ 210.118513][ C0] ? blk_mq_end_request+0x4b/0x480 [ 210.119572][ C0] ? blk_done_softirq+0x21d/0x340 [ 210.120628][ C0] ? __do_softirq+0x190/0x611 [ 210.121626][ C0] crypt_convert+0x29f9/0x4c00 [ 210.122668][ C0] ? _raw_spin_lock_irqsave+0x87/0xe0 [ 210.123824][ C0] ? kasan_set_track+0x1c/0x30 [ 210.124858][ C0] ? crypt_iv_tcw_ctr+0x4a0/0x4a0 [ 210.125930][ C0] ? kmem_cache_free+0x104/0x470 [ 210.126973][ C0] ? crypt_endio+0x91/0x180 [ 210.127947][ C0] kcryptd_crypt_read_convert+0x30e/0x420 [ 210.129165][ C0] blk_update_request+0x757/0x1150 [ 210.130231][ C0] blk_mq_end_request+0x4b/0x480 [ 210.131294][ C0] blk_done_softirq+0x21d/0x340 [ 210.132332][ C0] ? _raw_spin_lock+0x81/0xd0 [ 210.133289][ C0] ? blk_mq_stop_hw_queue+0x30/0x30 [ 210.134399][ C0] ? _raw_read_lock_irq+0x40/0x40 [ 210.135458][ C0] __do_softirq+0x190/0x611 [ 210.136409][ C0] ? handle_edge_irq+0x221/0xb60 [ 210.137447][ C0] asm_call_irq_on_stack+0x12/0x20 [ 210.138507][ C0] </IRQ> [ 210.139118][ C0] do_softirq_own_stack+0x37/0x40 [ 210.140191][ C0] irq_exit_rcu+0x110/0x1b0 [ 210.141151][ C0] common_interrupt+0x74/0x120 [ 210.142171][ C0] asm_common_interrupt+0x1e/0x40 Fix this by allocating crypto requests with GFP_ATOMIC mask in interrupt context. Fixes: 39d42fa96ba1 ("dm crypt: add flags to optionally bypass kcryptd workqueues") Cc: sta...@vger.kernel.org # v5.9+ Reported-by: Maciej S. Szmigiero <m...@maciej.szmigiero.name> Signed-off-by: Ignat Korchagin <ig...@cloudflare.com> Acked-by: Mikulas Patocka <mpato...@redhat.com> Signed-off-by: Mike Snitzer <snit...@redhat.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- drivers/md/dm-crypt.c | 35 +++++++++++++++++++++++++---------- 1 file changed, 25 insertions(+), 10 deletions(-) --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -1454,13 +1454,16 @@ static int crypt_convert_block_skcipher( static void kcryptd_async_done(struct crypto_async_request *async_req, int error); -static void crypt_alloc_req_skcipher(struct crypt_config *cc, +static int crypt_alloc_req_skcipher(struct crypt_config *cc, struct convert_context *ctx) { unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1); - if (!ctx->r.req) - ctx->r.req = mempool_alloc(&cc->req_pool, GFP_NOIO); + if (!ctx->r.req) { + ctx->r.req = mempool_alloc(&cc->req_pool, in_interrupt() ? GFP_ATOMIC : GFP_NOIO); + if (!ctx->r.req) + return -ENOMEM; + } skcipher_request_set_tfm(ctx->r.req, cc->cipher_tfm.tfms[key_index]); @@ -1471,13 +1474,18 @@ static void crypt_alloc_req_skcipher(str skcipher_request_set_callback(ctx->r.req, CRYPTO_TFM_REQ_MAY_BACKLOG, kcryptd_async_done, dmreq_of_req(cc, ctx->r.req)); + + return 0; } -static void crypt_alloc_req_aead(struct crypt_config *cc, +static int crypt_alloc_req_aead(struct crypt_config *cc, struct convert_context *ctx) { - if (!ctx->r.req_aead) - ctx->r.req_aead = mempool_alloc(&cc->req_pool, GFP_NOIO); + if (!ctx->r.req) { + ctx->r.req = mempool_alloc(&cc->req_pool, in_interrupt() ? GFP_ATOMIC : GFP_NOIO); + if (!ctx->r.req) + return -ENOMEM; + } aead_request_set_tfm(ctx->r.req_aead, cc->cipher_tfm.tfms_aead[0]); @@ -1488,15 +1496,17 @@ static void crypt_alloc_req_aead(struct aead_request_set_callback(ctx->r.req_aead, CRYPTO_TFM_REQ_MAY_BACKLOG, kcryptd_async_done, dmreq_of_req(cc, ctx->r.req_aead)); + + return 0; } -static void crypt_alloc_req(struct crypt_config *cc, +static int crypt_alloc_req(struct crypt_config *cc, struct convert_context *ctx) { if (crypt_integrity_aead(cc)) - crypt_alloc_req_aead(cc, ctx); + return crypt_alloc_req_aead(cc, ctx); else - crypt_alloc_req_skcipher(cc, ctx); + return crypt_alloc_req_skcipher(cc, ctx); } static void crypt_free_req_skcipher(struct crypt_config *cc, @@ -1539,7 +1549,12 @@ static blk_status_t crypt_convert(struct while (ctx->iter_in.bi_size && ctx->iter_out.bi_size) { - crypt_alloc_req(cc, ctx); + r = crypt_alloc_req(cc, ctx); + if (r) { + complete(&ctx->restart); + return BLK_STS_DEV_RESOURCE; + } + atomic_inc(&ctx->cc_pending); if (crypt_integrity_aead(cc))