Re: [PATCH] async_pq: Remove VLA usage

2018-05-04 Thread kbuild test robot 
Hi Kyle,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on cryptodev/master]
[also build test ERROR on v4.17-rc3 next-20180504]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:
https://github.com/0day-ci/linux/commits/Kyle-Spiers/async_pq-Remove-VLA-usage/20180505-012638
base:   
https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git master
config: sparc64-allmodconfig (attached as .config)
compiler: sparc64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
wget 
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O 
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=sparc64 

All error/warnings (new ones prefixed by >>):

   crypto/async_tx/raid6test.c: In function 'raid6_dual_recov':
>> crypto/async_tx/raid6test.c:89:13: error: implicit declaration of function 
>> 'kmalloc_array'; did you mean 'kvmalloc_array'? 
>> [-Werror=implicit-function-declaration]
   blocks = kmalloc_array(disks, sizeof(*blocks),
^
kvmalloc_array
>> crypto/async_tx/raid6test.c:89:11: warning: assignment makes pointer from 
>> integer without a cast [-Wint-conversion]
   blocks = kmalloc_array(disks, sizeof(*blocks),
  ^
>> crypto/async_tx/raid6test.c:109:4: error: implicit declaration of function 
>> 'kfree'; did you mean 'kvfree'? [-Werror=implicit-function-declaration]
   kfree(blocks);
   ^
   kvfree
   cc1: some warnings being treated as errors

vim +89 crypto/async_tx/raid6test.c

66  
67  /* Recover two failed blocks. */
68  static void raid6_dual_recov(int disks, size_t bytes, int faila, int 
failb, struct page **ptrs)
69  {
70  struct async_submit_ctl submit;
71  struct completion cmp;
72  struct dma_async_tx_descriptor *tx = NULL;
73  enum sum_check_flags result = ~0;
74  
75  if (faila > failb)
76  swap(faila, failb);
77  
78  if (failb == disks-1) {
79  if (faila == disks-2) {
80  /* P+Q failure.  Just rebuild the syndrome. */
81  init_async_submit(, 0, NULL, NULL, NULL, 
addr_conv);
82  tx = async_gen_syndrome(ptrs, 0, disks, bytes, 
);
83  } else {
84  struct page **blocks;
85  struct page *dest;
86  int count = 0;
87  int i;
88  
  > 89  blocks = kmalloc_array(disks, sizeof(*blocks),
90  GFP_KERNEL);
91  if (!blocks)
92  return;
93  
94  /* data+Q failure.  Reconstruct data from P,
95   * then rebuild syndrome
96   */
97  for (i = disks; i-- ; ) {
98  if (i == faila || i == failb)
99  continue;
   100  blocks[count++] = ptrs[i];
   101  }
   102  dest = ptrs[faila];
   103  init_async_submit(, 
ASYNC_TX_XOR_ZERO_DST, NULL,
   104NULL, NULL, addr_conv);
   105  tx = async_xor(dest, blocks, 0, count, bytes, 
);
   106  
   107  init_async_submit(, 0, tx, NULL, NULL, 
addr_conv);
   108  tx = async_gen_syndrome(ptrs, 0, disks, bytes, 
);
 > 109  kfree(blocks);
   110  }
   111  } else {
   112  if (failb == disks-2) {
   113  /* data+P failure. */
   114  init_async_submit(, 0, NULL, NULL, NULL, 
addr_conv);
   115  tx = async_raid6_datap_recov(disks, bytes, 
faila, ptrs, );
   116  } else {
   117  /* data+data failure. */
   118  init_async_submit(, 0, NULL, NULL, NULL, 
addr_conv);
   119  tx = async_raid6_2data_recov(disks, bytes, 
faila, failb, ptrs, );
   120  }
   121  }
   122  init_completion();
   123  init_async_submit(, ASYNC_TX_ACK, tx, callback, , 
addr_conv);
   124  tx = async_syndrome_val(ptrs, 0, disks, bytes, , spare, 
);
   125  async_tx_issue_pending(tx);
   126  
   127  if (wait_for_completion_timeout(, msecs_to_jiffies(3000)) 
== 0)
   128  pr("%s: timeout! (faila: %d failb: %d disks: %d)\n",
   129

Re: [PATCH] async_pq: Remove VLA usage

2018-05-04 Thread kbuild test robot 
Hi Kyle,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on cryptodev/master]
[also build test ERROR on v4.17-rc3 next-20180504]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:
https://github.com/0day-ci/linux/commits/Kyle-Spiers/async_pq-Remove-VLA-usage/20180505-012638
base:   
https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git master
config: sparc64-allmodconfig (attached as .config)
compiler: sparc64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
wget 
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O 
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=sparc64 

All error/warnings (new ones prefixed by >>):

   crypto/async_tx/raid6test.c: In function 'raid6_dual_recov':
>> crypto/async_tx/raid6test.c:89:13: error: implicit declaration of function 
>> 'kmalloc_array'; did you mean 'kvmalloc_array'? 
>> [-Werror=implicit-function-declaration]
   blocks = kmalloc_array(disks, sizeof(*blocks),
^
kvmalloc_array
>> crypto/async_tx/raid6test.c:89:11: warning: assignment makes pointer from 
>> integer without a cast [-Wint-conversion]
   blocks = kmalloc_array(disks, sizeof(*blocks),
  ^
>> crypto/async_tx/raid6test.c:109:4: error: implicit declaration of function 
>> 'kfree'; did you mean 'kvfree'? [-Werror=implicit-function-declaration]
   kfree(blocks);
   ^
   kvfree
   cc1: some warnings being treated as errors

vim +89 crypto/async_tx/raid6test.c

66  
67  /* Recover two failed blocks. */
68  static void raid6_dual_recov(int disks, size_t bytes, int faila, int 
failb, struct page **ptrs)
69  {
70  struct async_submit_ctl submit;
71  struct completion cmp;
72  struct dma_async_tx_descriptor *tx = NULL;
73  enum sum_check_flags result = ~0;
74  
75  if (faila > failb)
76  swap(faila, failb);
77  
78  if (failb == disks-1) {
79  if (faila == disks-2) {
80  /* P+Q failure.  Just rebuild the syndrome. */
81  init_async_submit(, 0, NULL, NULL, NULL, 
addr_conv);
82  tx = async_gen_syndrome(ptrs, 0, disks, bytes, 
);
83  } else {
84  struct page **blocks;
85  struct page *dest;
86  int count = 0;
87  int i;
88  
  > 89  blocks = kmalloc_array(disks, sizeof(*blocks),
90  GFP_KERNEL);
91  if (!blocks)
92  return;
93  
94  /* data+Q failure.  Reconstruct data from P,
95   * then rebuild syndrome
96   */
97  for (i = disks; i-- ; ) {
98  if (i == faila || i == failb)
99  continue;
   100  blocks[count++] = ptrs[i];
   101  }
   102  dest = ptrs[faila];
   103  init_async_submit(, 
ASYNC_TX_XOR_ZERO_DST, NULL,
   104NULL, NULL, addr_conv);
   105  tx = async_xor(dest, blocks, 0, count, bytes, 
);
   106  
   107  init_async_submit(, 0, tx, NULL, NULL, 
addr_conv);
   108  tx = async_gen_syndrome(ptrs, 0, disks, bytes, 
);
 > 109  kfree(blocks);
   110  }
   111  } else {
   112  if (failb == disks-2) {
   113  /* data+P failure. */
   114  init_async_submit(, 0, NULL, NULL, NULL, 
addr_conv);
   115  tx = async_raid6_datap_recov(disks, bytes, 
faila, ptrs, );
   116  } else {
   117  /* data+data failure. */
   118  init_async_submit(, 0, NULL, NULL, NULL, 
addr_conv);
   119  tx = async_raid6_2data_recov(disks, bytes, 
faila, failb, ptrs, );
   120  }
   121  }
   122  init_completion();
   123  init_async_submit(, ASYNC_TX_ACK, tx, callback, , 
addr_conv);
   124  tx = async_syndrome_val(ptrs, 0, disks, bytes, , spare, 
);
   125  async_tx_issue_pending(tx);
   126  
   127  if (wait_for_completion_timeout(, msecs_to_jiffies(3000)) 
== 0)
   128  pr("%s: timeout! (faila: %d failb: %d disks: %d)\n",
   129

Re: [PATCH] async_pq: Remove VLA usage

2018-05-03 Thread Kees Cook 
On Thu, May 3, 2018 at 3:57 PM, Kyle Spiers  wrote:
> In the quest to remove VLAs from the kernel[1], this moves the
> allocation of coefs and blocks from the stack to being kmalloc()ed.
>
> [1] https://lkml.org/lkml/2018/3/7/621
>
> Signed-off-by: Kyle Spiers 

Reviewed-by: Kees Cook 

Thanks for working on this one!

-Kees

> ---
>  crypto/async_tx/async_pq.c  | 18 ++
>  crypto/async_tx/raid6test.c |  8 +++-
>  2 files changed, 21 insertions(+), 5 deletions(-)
>
> diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
> index 56bd612927ab..af1912313a23 100644
> --- a/crypto/async_tx/async_pq.c
> +++ b/crypto/async_tx/async_pq.c
> @@ -194,9 +194,9 @@ async_gen_syndrome(struct page **blocks, unsigned int 
> offset, int disks,
> (src_cnt <= dma_maxpq(device, 0) ||
>  dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
> is_dma_pq_aligned(device, offset, 0, len)) {
> -   struct dma_async_tx_descriptor *tx;
> +   struct dma_async_tx_descriptor *tx = NULL;
> enum dma_ctrl_flags dma_flags = 0;
> -   unsigned char coefs[src_cnt];
> +   unsigned char *coefs;
> int i, j;
>
> /* run the p+q asynchronously */
> @@ -207,6 +207,9 @@ async_gen_syndrome(struct page **blocks, unsigned int 
> offset, int disks,
>  * sources and update the coefficients accordingly
>  */
> unmap->len = len;
> +   coefs = kmalloc_array(src_cnt, sizeof(*coefs), GFP_KERNEL);
> +   if (!coefs)
> +   goto out;
> for (i = 0, j = 0; i < src_cnt; i++) {
> if (blocks[i] == NULL)
> continue;
> @@ -240,7 +243,9 @@ async_gen_syndrome(struct page **blocks, unsigned int 
> offset, int disks,
> }
>
> tx = do_async_gen_syndrome(chan, coefs, j, unmap, dma_flags, 
> submit);
> +out:
> dmaengine_unmap_put(unmap);
> +   kfree(coefs);
> return tx;
> }
>
> @@ -298,8 +303,8 @@ async_syndrome_val(struct page **blocks, unsigned int 
> offset, int disks,
>  {
> struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
> struct dma_device *device = chan ? chan->device : NULL;
> -   struct dma_async_tx_descriptor *tx;
> -   unsigned char coefs[disks-2];
> +   struct dma_async_tx_descriptor *tx = NULL;
> +   unsigned char *coefs = NULL;
> enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 
> 0;
> struct dmaengine_unmap_data *unmap = NULL;
>
> @@ -318,6 +323,9 @@ async_syndrome_val(struct page **blocks, unsigned int 
> offset, int disks,
>  __func__, disks, len);
>
> unmap->len = len;
> +   coefs = kmalloc_array(disks - 2, sizeof(*coefs), GFP_KERNEL);
> +   if (!coefs)
> +   goto out;
> for (i = 0; i < disks-2; i++)
> if (likely(blocks[i])) {
> unmap->addr[j] = dma_map_page(dev, blocks[i],
> @@ -423,6 +431,8 @@ async_syndrome_val(struct page **blocks, unsigned int 
> offset, int disks,
> async_tx_sync_epilog(submit);
> tx = NULL;
> }
> +out:
> +   kfree(coefs);
> dmaengine_unmap_put(unmap);
>
> return tx;
> diff --git a/crypto/async_tx/raid6test.c b/crypto/async_tx/raid6test.c
> index dad95f45b88f..ea036b531ef2 100644
> --- a/crypto/async_tx/raid6test.c
> +++ b/crypto/async_tx/raid6test.c
> @@ -81,11 +81,16 @@ static void raid6_dual_recov(int disks, size_t bytes, int 
> faila, int failb, stru
> init_async_submit(, 0, NULL, NULL, NULL, 
> addr_conv);
> tx = async_gen_syndrome(ptrs, 0, disks, bytes, 
> );
> } else {
> -   struct page *blocks[disks];
> +   struct page **blocks;
> struct page *dest;
> int count = 0;
> int i;
>
> +   blocks = kmalloc_array(disks, sizeof(*blocks),
> +   GFP_KERNEL);
> +   if (!blocks)
> +   return;
> +
> /* data+Q failure.  Reconstruct data from P,
>  * then rebuild syndrome
>  */
> @@ -101,6 +106,7 @@ static void raid6_dual_recov(int disks, size_t bytes, int 
> faila, int failb, stru
>
> init_async_submit(, 0, tx, NULL, NULL, 
> addr_conv);
> tx = async_gen_syndrome(ptrs, 0, disks, bytes, 
> );
> +   kfree(blocks);
> }
> } else {
>

Re: [PATCH] async_pq: Remove VLA usage

2018-05-03 Thread Kees Cook 
On Thu, May 3, 2018 at 3:57 PM, Kyle Spiers  wrote:
> In the quest to remove VLAs from the kernel[1], this moves the
> allocation of coefs and blocks from the stack to being kmalloc()ed.
>
> [1] https://lkml.org/lkml/2018/3/7/621
>
> Signed-off-by: Kyle Spiers 

Reviewed-by: Kees Cook 

Thanks for working on this one!

-Kees

> ---
>  crypto/async_tx/async_pq.c  | 18 ++
>  crypto/async_tx/raid6test.c |  8 +++-
>  2 files changed, 21 insertions(+), 5 deletions(-)
>
> diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
> index 56bd612927ab..af1912313a23 100644
> --- a/crypto/async_tx/async_pq.c
> +++ b/crypto/async_tx/async_pq.c
> @@ -194,9 +194,9 @@ async_gen_syndrome(struct page **blocks, unsigned int 
> offset, int disks,
> (src_cnt <= dma_maxpq(device, 0) ||
>  dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
> is_dma_pq_aligned(device, offset, 0, len)) {
> -   struct dma_async_tx_descriptor *tx;
> +   struct dma_async_tx_descriptor *tx = NULL;
> enum dma_ctrl_flags dma_flags = 0;
> -   unsigned char coefs[src_cnt];
> +   unsigned char *coefs;
> int i, j;
>
> /* run the p+q asynchronously */
> @@ -207,6 +207,9 @@ async_gen_syndrome(struct page **blocks, unsigned int 
> offset, int disks,
>  * sources and update the coefficients accordingly
>  */
> unmap->len = len;
> +   coefs = kmalloc_array(src_cnt, sizeof(*coefs), GFP_KERNEL);
> +   if (!coefs)
> +   goto out;
> for (i = 0, j = 0; i < src_cnt; i++) {
> if (blocks[i] == NULL)
> continue;
> @@ -240,7 +243,9 @@ async_gen_syndrome(struct page **blocks, unsigned int 
> offset, int disks,
> }
>
> tx = do_async_gen_syndrome(chan, coefs, j, unmap, dma_flags, 
> submit);
> +out:
> dmaengine_unmap_put(unmap);
> +   kfree(coefs);
> return tx;
> }
>
> @@ -298,8 +303,8 @@ async_syndrome_val(struct page **blocks, unsigned int 
> offset, int disks,
>  {
> struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
> struct dma_device *device = chan ? chan->device : NULL;
> -   struct dma_async_tx_descriptor *tx;
> -   unsigned char coefs[disks-2];
> +   struct dma_async_tx_descriptor *tx = NULL;
> +   unsigned char *coefs = NULL;
> enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 
> 0;
> struct dmaengine_unmap_data *unmap = NULL;
>
> @@ -318,6 +323,9 @@ async_syndrome_val(struct page **blocks, unsigned int 
> offset, int disks,
>  __func__, disks, len);
>
> unmap->len = len;
> +   coefs = kmalloc_array(disks - 2, sizeof(*coefs), GFP_KERNEL);
> +   if (!coefs)
> +   goto out;
> for (i = 0; i < disks-2; i++)
> if (likely(blocks[i])) {
> unmap->addr[j] = dma_map_page(dev, blocks[i],
> @@ -423,6 +431,8 @@ async_syndrome_val(struct page **blocks, unsigned int 
> offset, int disks,
> async_tx_sync_epilog(submit);
> tx = NULL;
> }
> +out:
> +   kfree(coefs);
> dmaengine_unmap_put(unmap);
>
> return tx;
> diff --git a/crypto/async_tx/raid6test.c b/crypto/async_tx/raid6test.c
> index dad95f45b88f..ea036b531ef2 100644
> --- a/crypto/async_tx/raid6test.c
> +++ b/crypto/async_tx/raid6test.c
> @@ -81,11 +81,16 @@ static void raid6_dual_recov(int disks, size_t bytes, int 
> faila, int failb, stru
> init_async_submit(, 0, NULL, NULL, NULL, 
> addr_conv);
> tx = async_gen_syndrome(ptrs, 0, disks, bytes, 
> );
> } else {
> -   struct page *blocks[disks];
> +   struct page **blocks;
> struct page *dest;
> int count = 0;
> int i;
>
> +   blocks = kmalloc_array(disks, sizeof(*blocks),
> +   GFP_KERNEL);
> +   if (!blocks)
> +   return;
> +
> /* data+Q failure.  Reconstruct data from P,
>  * then rebuild syndrome
>  */
> @@ -101,6 +106,7 @@ static void raid6_dual_recov(int disks, size_t bytes, int 
> faila, int failb, stru
>
> init_async_submit(, 0, tx, NULL, NULL, 
> addr_conv);
> tx = async_gen_syndrome(ptrs, 0, disks, bytes, 
> );
> +   kfree(blocks);
> }
> } else {
> if (failb == disks-2) {
> --
> 2.17.0.441.gb46fe60e1d-goog
>

[PATCH] async_pq: Remove VLA usage

2018-05-03 Thread Kyle Spiers 
In the quest to remove VLAs from the kernel[1], this moves the
allocation of coefs and blocks from the stack to being kmalloc()ed.

[1] https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Kyle Spiers 
---
 crypto/async_tx/async_pq.c  | 18 ++
 crypto/async_tx/raid6test.c |  8 +++-
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index 56bd612927ab..af1912313a23 100644
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -194,9 +194,9 @@ async_gen_syndrome(struct page **blocks, unsigned int 
offset, int disks,
(src_cnt <= dma_maxpq(device, 0) ||
 dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
is_dma_pq_aligned(device, offset, 0, len)) {
-   struct dma_async_tx_descriptor *tx;
+   struct dma_async_tx_descriptor *tx = NULL;
enum dma_ctrl_flags dma_flags = 0;
-   unsigned char coefs[src_cnt];
+   unsigned char *coefs;
int i, j;
 
/* run the p+q asynchronously */
@@ -207,6 +207,9 @@ async_gen_syndrome(struct page **blocks, unsigned int 
offset, int disks,
 * sources and update the coefficients accordingly
 */
unmap->len = len;
+   coefs = kmalloc_array(src_cnt, sizeof(*coefs), GFP_KERNEL);
+   if (!coefs)
+   goto out;
for (i = 0, j = 0; i < src_cnt; i++) {
if (blocks[i] == NULL)
continue;
@@ -240,7 +243,9 @@ async_gen_syndrome(struct page **blocks, unsigned int 
offset, int disks,
}
 
tx = do_async_gen_syndrome(chan, coefs, j, unmap, dma_flags, 
submit);
+out:
dmaengine_unmap_put(unmap);
+   kfree(coefs);
return tx;
}
 
@@ -298,8 +303,8 @@ async_syndrome_val(struct page **blocks, unsigned int 
offset, int disks,
 {
struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
struct dma_device *device = chan ? chan->device : NULL;
-   struct dma_async_tx_descriptor *tx;
-   unsigned char coefs[disks-2];
+   struct dma_async_tx_descriptor *tx = NULL;
+   unsigned char *coefs = NULL;
enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
struct dmaengine_unmap_data *unmap = NULL;
 
@@ -318,6 +323,9 @@ async_syndrome_val(struct page **blocks, unsigned int 
offset, int disks,
 __func__, disks, len);
 
unmap->len = len;
+   coefs = kmalloc_array(disks - 2, sizeof(*coefs), GFP_KERNEL);
+   if (!coefs)
+   goto out;
for (i = 0; i < disks-2; i++)
if (likely(blocks[i])) {
unmap->addr[j] = dma_map_page(dev, blocks[i],
@@ -423,6 +431,8 @@ async_syndrome_val(struct page **blocks, unsigned int 
offset, int disks,
async_tx_sync_epilog(submit);
tx = NULL;
}
+out:
+   kfree(coefs);
dmaengine_unmap_put(unmap);
 
return tx;
diff --git a/crypto/async_tx/raid6test.c b/crypto/async_tx/raid6test.c
index dad95f45b88f..ea036b531ef2 100644
--- a/crypto/async_tx/raid6test.c
+++ b/crypto/async_tx/raid6test.c
@@ -81,11 +81,16 @@ static void raid6_dual_recov(int disks, size_t bytes, int 
faila, int failb, stru
init_async_submit(, 0, NULL, NULL, NULL, 
addr_conv);
tx = async_gen_syndrome(ptrs, 0, disks, bytes, );
} else {
-   struct page *blocks[disks];
+   struct page **blocks;
struct page *dest;
int count = 0;
int i;
 
+   blocks = kmalloc_array(disks, sizeof(*blocks),
+   GFP_KERNEL);
+   if (!blocks)
+   return;
+
/* data+Q failure.  Reconstruct data from P,
 * then rebuild syndrome
 */
@@ -101,6 +106,7 @@ static void raid6_dual_recov(int disks, size_t bytes, int 
faila, int failb, stru
 
init_async_submit(, 0, tx, NULL, NULL, 
addr_conv);
tx = async_gen_syndrome(ptrs, 0, disks, bytes, );
+   kfree(blocks);
}
} else {
if (failb == disks-2) {
-- 
2.17.0.441.gb46fe60e1d-goog

[PATCH] async_pq: Remove VLA usage

2018-05-03 Thread Kyle Spiers 
In the quest to remove VLAs from the kernel[1], this moves the
allocation of coefs and blocks from the stack to being kmalloc()ed.

[1] https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Kyle Spiers 
---
 crypto/async_tx/async_pq.c  | 18 ++
 crypto/async_tx/raid6test.c |  8 +++-
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index 56bd612927ab..af1912313a23 100644
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -194,9 +194,9 @@ async_gen_syndrome(struct page **blocks, unsigned int 
offset, int disks,
(src_cnt <= dma_maxpq(device, 0) ||
 dma_maxpq(device, DMA_PREP_CONTINUE) > 0) &&
is_dma_pq_aligned(device, offset, 0, len)) {
-   struct dma_async_tx_descriptor *tx;
+   struct dma_async_tx_descriptor *tx = NULL;
enum dma_ctrl_flags dma_flags = 0;
-   unsigned char coefs[src_cnt];
+   unsigned char *coefs;
int i, j;
 
/* run the p+q asynchronously */
@@ -207,6 +207,9 @@ async_gen_syndrome(struct page **blocks, unsigned int 
offset, int disks,
 * sources and update the coefficients accordingly
 */
unmap->len = len;
+   coefs = kmalloc_array(src_cnt, sizeof(*coefs), GFP_KERNEL);
+   if (!coefs)
+   goto out;
for (i = 0, j = 0; i < src_cnt; i++) {
if (blocks[i] == NULL)
continue;
@@ -240,7 +243,9 @@ async_gen_syndrome(struct page **blocks, unsigned int 
offset, int disks,
}
 
tx = do_async_gen_syndrome(chan, coefs, j, unmap, dma_flags, 
submit);
+out:
dmaengine_unmap_put(unmap);
+   kfree(coefs);
return tx;
}
 
@@ -298,8 +303,8 @@ async_syndrome_val(struct page **blocks, unsigned int 
offset, int disks,
 {
struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
struct dma_device *device = chan ? chan->device : NULL;
-   struct dma_async_tx_descriptor *tx;
-   unsigned char coefs[disks-2];
+   struct dma_async_tx_descriptor *tx = NULL;
+   unsigned char *coefs = NULL;
enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
struct dmaengine_unmap_data *unmap = NULL;
 
@@ -318,6 +323,9 @@ async_syndrome_val(struct page **blocks, unsigned int 
offset, int disks,
 __func__, disks, len);
 
unmap->len = len;
+   coefs = kmalloc_array(disks - 2, sizeof(*coefs), GFP_KERNEL);
+   if (!coefs)
+   goto out;
for (i = 0; i < disks-2; i++)
if (likely(blocks[i])) {
unmap->addr[j] = dma_map_page(dev, blocks[i],
@@ -423,6 +431,8 @@ async_syndrome_val(struct page **blocks, unsigned int 
offset, int disks,
async_tx_sync_epilog(submit);
tx = NULL;
}
+out:
+   kfree(coefs);
dmaengine_unmap_put(unmap);
 
return tx;
diff --git a/crypto/async_tx/raid6test.c b/crypto/async_tx/raid6test.c
index dad95f45b88f..ea036b531ef2 100644
--- a/crypto/async_tx/raid6test.c
+++ b/crypto/async_tx/raid6test.c
@@ -81,11 +81,16 @@ static void raid6_dual_recov(int disks, size_t bytes, int 
faila, int failb, stru
init_async_submit(, 0, NULL, NULL, NULL, 
addr_conv);
tx = async_gen_syndrome(ptrs, 0, disks, bytes, );
} else {
-   struct page *blocks[disks];
+   struct page **blocks;
struct page *dest;
int count = 0;
int i;
 
+   blocks = kmalloc_array(disks, sizeof(*blocks),
+   GFP_KERNEL);
+   if (!blocks)
+   return;
+
/* data+Q failure.  Reconstruct data from P,
 * then rebuild syndrome
 */
@@ -101,6 +106,7 @@ static void raid6_dual_recov(int disks, size_t bytes, int 
faila, int failb, stru
 
init_async_submit(, 0, tx, NULL, NULL, 
addr_conv);
tx = async_gen_syndrome(ptrs, 0, disks, bytes, );
+   kfree(blocks);
}
} else {
if (failb == disks-2) {
-- 
2.17.0.441.gb46fe60e1d-goog