dm-crypt: remove per-cpu structure
-Remove per-cpu structure and make it per-convert_context instead.
-This allows moving requests between different cpus.
+Dm-crypt used per-cpu structures to hold pointers to ablkcipher_request.
+The code assumed that the work item keeps executing on a single CPU, so it
+used no synchronization when accessing this structure.
+
+When we disable a CPU by writing zero to
+/sys/devices/system/cpu/cpu*/online, the work item could be moved to
+another CPU. This causes crashes in dm-crypt because the code starts using
+a wrong ablkcipher_request.
+
+This patch fixes this bug by removing the percpu definition. The structure
+ablkcipher_request is accessed via a pointer from convert_context.
+Consequently, if the work item is rescheduled to a different CPU, the
+thread still uses the same ablkcipher_request.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
+Cc: stable@vger.kernel.org
---
drivers/md/dm-crypt.c | 61 +++++++++-----------------------------------------
1 file changed, 12 insertions(+), 49 deletions(-)
-Index: linux-3.10.4-fast/drivers/md/dm-crypt.c
+Index: linux-3.14-rc1/drivers/md/dm-crypt.c
===================================================================
---- linux-3.10.4-fast.orig/drivers/md/dm-crypt.c 2013-07-31 16:59:48.000000000 +0200
-+++ linux-3.10.4-fast/drivers/md/dm-crypt.c 2013-07-31 17:03:10.000000000 +0200
-@@ -18,7 +18,6 @@
+--- linux-3.14-rc1.orig/drivers/md/dm-crypt.c 2014-02-03 19:18:23.000000000 +0100
++++ linux-3.14-rc1/drivers/md/dm-crypt.c 2014-02-03 19:21:35.000000000 +0100
+@@ -19,7 +19,6 @@
#include <linux/crypto.h>
#include <linux/workqueue.h>
#include <linux/backing-dev.h>
#include <linux/atomic.h>
#include <linux/scatterlist.h>
#include <asm/page.h>
-@@ -44,6 +43,7 @@ struct convert_context {
- unsigned int idx_out;
+@@ -43,6 +42,7 @@ struct convert_context {
+ struct bvec_iter iter_out;
sector_t cc_sector;
atomic_t cc_pending;
+ struct ablkcipher_request *req;
};
/*
-@@ -105,15 +105,7 @@ struct iv_lmk_private {
+@@ -111,15 +111,7 @@ struct iv_tcw_private {
enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
/*
*/
struct crypt_config {
struct dm_dev *dev;
-@@ -143,12 +135,6 @@ struct crypt_config {
+@@ -150,12 +142,6 @@ struct crypt_config {
sector_t iv_offset;
unsigned int iv_size;
/* ESSIV: struct crypto_cipher *essiv_tfm */
void *iv_private;
struct crypto_ablkcipher **tfms;
-@@ -184,11 +170,6 @@ static void clone_init(struct dm_crypt_i
+@@ -192,11 +178,6 @@ static void clone_init(struct dm_crypt_i
static void kcryptd_queue_crypt(struct dm_crypt_io *io);
static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq);
/*
* Use this to access cipher attributes that are the same for each CPU.
*/
-@@ -738,16 +719,15 @@ static void kcryptd_async_done(struct cr
+@@ -903,16 +884,15 @@ static void kcryptd_async_done(struct cr
static void crypt_alloc_req(struct crypt_config *cc,
struct convert_context *ctx)
{
}
/*
-@@ -756,7 +736,6 @@ static void crypt_alloc_req(struct crypt
+@@ -921,7 +901,6 @@ static void crypt_alloc_req(struct crypt
static int crypt_convert(struct crypt_config *cc,
struct convert_context *ctx)
{
int r;
atomic_set(&ctx->cc_pending, 1);
-@@ -768,7 +747,7 @@ static int crypt_convert(struct crypt_co
+@@ -932,7 +911,7 @@ static int crypt_convert(struct crypt_co
atomic_inc(&ctx->cc_pending);
switch (r) {
/* async */
-@@ -777,7 +756,7 @@ static int crypt_convert(struct crypt_co
- INIT_COMPLETION(ctx->restart);
+@@ -941,7 +920,7 @@ static int crypt_convert(struct crypt_co
+ reinit_completion(&ctx->restart);
/* fall through*/
case -EINPROGRESS:
- this_cc->req = NULL;
ctx->cc_sector++;
continue;
-@@ -876,6 +855,7 @@ static struct dm_crypt_io *crypt_io_allo
+@@ -1040,6 +1019,7 @@ static struct dm_crypt_io *crypt_io_allo
io->sector = sector;
io->error = 0;
io->base_io = NULL;
atomic_set(&io->io_pending, 0);
return io;
-@@ -901,6 +881,8 @@ static void crypt_dec_pending(struct dm_
+@@ -1065,6 +1045,8 @@ static void crypt_dec_pending(struct dm_
if (!atomic_dec_and_test(&io->io_pending))
return;
mempool_free(io, cc->io_pool);
if (likely(!base_io))
-@@ -1326,8 +1308,6 @@ static int crypt_wipe_key(struct crypt_c
+@@ -1492,8 +1474,6 @@ static int crypt_wipe_key(struct crypt_c
static void crypt_dtr(struct dm_target *ti)
{
struct crypt_config *cc = ti->private;
ti->private = NULL;
-@@ -1339,13 +1319,6 @@ static void crypt_dtr(struct dm_target *
+@@ -1505,13 +1485,6 @@ static void crypt_dtr(struct dm_target *
if (cc->crypt_queue)
destroy_workqueue(cc->crypt_queue);
crypt_free_tfms(cc);
if (cc->bs)
-@@ -1364,9 +1337,6 @@ static void crypt_dtr(struct dm_target *
+@@ -1530,9 +1503,6 @@ static void crypt_dtr(struct dm_target *
if (cc->dev)
dm_put_device(ti, cc->dev);
kzfree(cc->cipher);
kzfree(cc->cipher_string);
-@@ -1421,13 +1391,6 @@ static int crypt_ctr_cipher(struct dm_ta
+@@ -1588,13 +1558,6 @@ static int crypt_ctr_cipher(struct dm_ta
if (tmp)
DMWARN("Ignoring unexpected additional cipher options");
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