linux-kernel - [PATCH 4.19 28/73] s390/crypto: fix possible sleep during spinlock aquired

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Date:   Fri,  7 Jun 2019 17:39:15 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Harald Freudenberger <freude@...ux.ibm.com>,
        Julian Wiedmann <jwi@...ux.ibm.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>
Subject: [PATCH 4.19 28/73] s390/crypto: fix possible sleep during spinlock aquired

From: Harald Freudenberger <freude@...ux.ibm.com>

commit 1c2c7029c008922d4d48902cc386250502e73d51 upstream.

This patch fixes a complain about possible sleep during
spinlock aquired
"BUG: sleeping function called from invalid context at
include/crypto/algapi.h:426"
for the ctr(aes) and ctr(des) s390 specific ciphers.

Instead of using a spinlock this patch introduces a mutex
which is save to be held in sleeping context. Please note
a deadlock is not possible as mutex_trylock() is used.

Signed-off-by: Harald Freudenberger <freude@...ux.ibm.com>
Reported-by: Julian Wiedmann <jwi@...ux.ibm.com>
Cc: stable@...r.kernel.org
Signed-off-by: Heiko Carstens <heiko.carstens@...ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/s390/crypto/aes_s390.c |    8 ++++----
 arch/s390/crypto/des_s390.c |    7 ++++---
 2 files changed, 8 insertions(+), 7 deletions(-)

--- a/arch/s390/crypto/aes_s390.c
+++ b/arch/s390/crypto/aes_s390.c
@@ -27,14 +27,14 @@
 #include <linux/module.h>
 #include <linux/cpufeature.h>
 #include <linux/init.h>
-#include <linux/spinlock.h>
+#include <linux/mutex.h>
 #include <linux/fips.h>
 #include <linux/string.h>
 #include <crypto/xts.h>
 #include <asm/cpacf.h>
 
 static u8 *ctrblk;
-static DEFINE_SPINLOCK(ctrblk_lock);
+static DEFINE_MUTEX(ctrblk_lock);
 
 static cpacf_mask_t km_functions, kmc_functions, kmctr_functions,
 		    kma_functions;
@@ -698,7 +698,7 @@ static int ctr_aes_crypt(struct blkciphe
 	unsigned int n, nbytes;
 	int ret, locked;
 
-	locked = spin_trylock(&ctrblk_lock);
+	locked = mutex_trylock(&ctrblk_lock);
 
 	ret = blkcipher_walk_virt_block(desc, walk, AES_BLOCK_SIZE);
 	while ((nbytes = walk->nbytes) >= AES_BLOCK_SIZE) {
@@ -716,7 +716,7 @@ static int ctr_aes_crypt(struct blkciphe
 		ret = blkcipher_walk_done(desc, walk, nbytes - n);
 	}
 	if (locked)
-		spin_unlock(&ctrblk_lock);
+		mutex_unlock(&ctrblk_lock);
 	/*
 	 * final block may be < AES_BLOCK_SIZE, copy only nbytes
 	 */
--- a/arch/s390/crypto/des_s390.c
+++ b/arch/s390/crypto/des_s390.c
@@ -14,6 +14,7 @@
 #include <linux/cpufeature.h>
 #include <linux/crypto.h>
 #include <linux/fips.h>
+#include <linux/mutex.h>
 #include <crypto/algapi.h>
 #include <crypto/des.h>
 #include <asm/cpacf.h>
@@ -21,7 +22,7 @@
 #define DES3_KEY_SIZE	(3 * DES_KEY_SIZE)
 
 static u8 *ctrblk;
-static DEFINE_SPINLOCK(ctrblk_lock);
+static DEFINE_MUTEX(ctrblk_lock);
 
 static cpacf_mask_t km_functions, kmc_functions, kmctr_functions;
 
@@ -387,7 +388,7 @@ static int ctr_desall_crypt(struct blkci
 	unsigned int n, nbytes;
 	int ret, locked;
 
-	locked = spin_trylock(&ctrblk_lock);
+	locked = mutex_trylock(&ctrblk_lock);
 
 	ret = blkcipher_walk_virt_block(desc, walk, DES_BLOCK_SIZE);
 	while ((nbytes = walk->nbytes) >= DES_BLOCK_SIZE) {
@@ -404,7 +405,7 @@ static int ctr_desall_crypt(struct blkci
 		ret = blkcipher_walk_done(desc, walk, nbytes - n);
 	}
 	if (locked)
-		spin_unlock(&ctrblk_lock);
+		mutex_unlock(&ctrblk_lock);
 	/* final block may be < DES_BLOCK_SIZE, copy only nbytes */
 	if (nbytes) {
 		cpacf_kmctr(fc, ctx->key, buf, walk->src.virt.addr,