Hi
This is the backport of the patch for 4.14.
Mikulas
From gregkh@linuxfoundation.org Sun Sep 23 15:18:04 2018
Date: Sun, 23 Sep 2018 21:17:27 +0200 From: gregkh@linuxfoundation.org To: mpatocka@redhat.com, snitzer@redhat.com Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] dm: disable CRYPTO_TFM_REQ_MAY_SLEEP to fix a GFP_KERNEL" failed to apply to 4.14-stable tree
The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 432061b3da64e488be3403124a72a9250bbe96d4 Mon Sep 17 00:00:00 2001
From: Mikulas Patocka mpatocka@redhat.com Date: Wed, 5 Sep 2018 09:17:45 -0400 Subject: [PATCH] dm: disable CRYPTO_TFM_REQ_MAY_SLEEP to fix a GFP_KERNEL recursion deadlock
There's a XFS on dm-crypt deadlock, recursing back to itself due to the crypto subsystems use of GFP_KERNEL, reported here: https://bugzilla.kernel.org/show_bug.cgi?id=200835
* dm-crypt calls crypt_convert in xts mode * init_crypt from xts.c calls kmalloc(GFP_KERNEL) * kmalloc(GFP_KERNEL) recurses into the XFS filesystem, the filesystem tries to submit some bios and wait for them, causing a deadlock
Fix this by updating both the DM crypt and integrity targets to no longer use the CRYPTO_TFM_REQ_MAY_SLEEP flag, which will change the crypto allocations from GFP_KERNEL to GFP_ATOMIC, therefore they can't recurse into a filesystem. A GFP_ATOMIC allocation can fail, but init_crypt() in xts.c handles the allocation failure gracefully - it will fall back to preallocated buffer if the allocation fails.
The crypto API maintainer says that the crypto API only needs to allocate memory when dealing with unaligned buffers and therefore turning CRYPTO_TFM_REQ_MAY_SLEEP off is safe (see this discussion: https://www.redhat.com/archives/dm-devel/2018-August/msg00195.html )
Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka mpatocka@redhat.com Signed-off-by: Mike Snitzer snitzer@redhat.com
--- drivers/md/dm-crypt.c | 10 +++++----- drivers/md/dm-integrity.c | 4 ++-- 2 files changed, 7 insertions(+), 7 deletions(-)
Index: linux-stable/drivers/md/dm-crypt.c =================================================================== --- linux-stable.orig/drivers/md/dm-crypt.c 2019-04-16 10:49:33.000000000 +0200 +++ linux-stable/drivers/md/dm-crypt.c 2019-04-16 10:51:15.000000000 +0200 @@ -334,7 +334,7 @@ static int crypt_iv_essiv_init(struct cr
sg_init_one(&sg, cc->key, cc->key_size); ahash_request_set_tfm(req, essiv->hash_tfm); - ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL); + ahash_request_set_callback(req, 0, NULL, NULL); ahash_request_set_crypt(req, &sg, essiv->salt, cc->key_size);
err = crypto_ahash_digest(req); @@ -609,7 +609,7 @@ static int crypt_iv_lmk_one(struct crypt int i, r;
desc->tfm = lmk->hash_tfm; - desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + desc->flags = 0;
r = crypto_shash_init(desc); if (r) @@ -771,7 +771,7 @@ static int crypt_iv_tcw_whitening(struct
/* calculate crc32 for every 32bit part and xor it */ desc->tfm = tcw->crc32_tfm; - desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + desc->flags = 0; for (i = 0; i < 4; i++) { r = crypto_shash_init(desc); if (r) @@ -1254,7 +1254,7 @@ static void crypt_alloc_req_skcipher(str * requests if driver request queue is full. */ skcipher_request_set_callback(ctx->r.req, - CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, + CRYPTO_TFM_REQ_MAY_BACKLOG, kcryptd_async_done, dmreq_of_req(cc, ctx->r.req)); }
@@ -1271,7 +1271,7 @@ static void crypt_alloc_req_aead(struct * requests if driver request queue is full. */ aead_request_set_callback(ctx->r.req_aead, - CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, + CRYPTO_TFM_REQ_MAY_BACKLOG, kcryptd_async_done, dmreq_of_req(cc, ctx->r.req_aead)); }
Index: linux-stable/drivers/md/dm-integrity.c =================================================================== --- linux-stable.orig/drivers/md/dm-integrity.c 2019-04-16 10:49:33.000000000 +0200 +++ linux-stable/drivers/md/dm-integrity.c 2019-04-16 10:49:33.000000000 +0200 @@ -493,7 +493,7 @@ static void section_mac(struct dm_integr unsigned j, size;
desc->tfm = ic->journal_mac; - desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; + desc->flags = 0;
r = crypto_shash_init(desc); if (unlikely(r)) { @@ -637,7 +637,7 @@ static void complete_journal_encrypt(str static bool do_crypt(bool encrypt, struct skcipher_request *req, struct journal_completion *comp) { int r; - skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, + skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, complete_journal_encrypt, comp); if (likely(encrypt)) r = crypto_skcipher_encrypt(req);