[PATCH 5.1 33/85] s390/crypto: fix possible sleep during spinlock aquired

From: Greg Kroah-Hartman
Date: Fri Jun 07 2019 - 11:54:12 EST


From: Harald Freudenberger <freude@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
Reported-by: Julian Wiedmann <jwi@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
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,