From 6688d6a5dd67fbbd666132859a5da7a950bd55c8 Mon Sep 17 00:00:00 2001 From: Ben Collins Date: Fri, 3 Apr 2015 16:09:46 +0000 Subject: [PATCH] dm crypt: fix deadlock when async crypto algorithm returns -EBUSY commit 0618764cb25f6fa9fb31152995de42a8a0496475 upstream. I suspect this doesn't show up for most anyone because software algorithms typically don't have a sense of being too busy. However, when working with the Freescale CAAM driver it will return -EBUSY on occasion under heavy -- which resulted in dm-crypt deadlock. After checking the logic in some other drivers, the scheme for crypt_convert() and it's callback, kcryptd_async_done(), were not correctly laid out to properly handle -EBUSY or -EINPROGRESS. Fix this by using the completion for both -EBUSY and -EINPROGRESS. Now crypt_convert()'s use of completion is comparable to af_alg_wait_for_completion(). Similarly, kcryptd_async_done() follows the pattern used in af_alg_complete(). Before this fix dm-crypt would lockup within 1-2 minutes running with the CAAM driver. Fix was regression tested against software algorithms on PPC32 and x86_64, and things seem perfectly happy there as well. Change-Id: I4750c93721392d358088b4ba04639af7e989192d Signed-off-by: Ben Collins Signed-off-by: Mike Snitzer [lizf: Backported to 3.4: adjust context] Signed-off-by: Zefan Li --- drivers/md/dm-crypt.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index 19391c1f3061..37da15abb98c 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -753,11 +753,10 @@ static int crypt_convert(struct crypt_config *cc, switch (r) { /* async */ + case -EINPROGRESS: case -EBUSY: wait_for_completion(&ctx->restart); INIT_COMPLETION(ctx->restart); - /* fall through*/ - case -EINPROGRESS: ctx->req = NULL; ctx->sector++; continue; @@ -1169,10 +1168,8 @@ static void kcryptd_async_done(struct crypto_async_request *async_req, struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx); struct crypt_config *cc = io->target->private; - if (error == -EINPROGRESS) { - complete(&ctx->restart); + if (error == -EINPROGRESS) return; - } if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post) error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq); @@ -1183,12 +1180,15 @@ static void kcryptd_async_done(struct crypto_async_request *async_req, mempool_free(req_of_dmreq(cc, dmreq), cc->req_pool); if (!atomic_dec_and_test(&ctx->pending)) - return; + goto done; if (bio_data_dir(io->base_bio) == READ) kcryptd_crypt_read_done(io); else kcryptd_crypt_write_io_submit(io, 1); +done: + if (!completion_done(&ctx->restart)) + complete(&ctx->restart); } static void kcryptd_crypt(struct work_struct *work)