diff mbox

async_pq: Remove VLA usage

Message ID 20180503225716.154235-1-ksspiers@google.com (mailing list archive)
State Not Applicable
Delegated to: Herbert Xu
Headers show

Commit Message

Kyle Spiers May 3, 2018, 10:57 p.m. UTC 
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 <ksspiers@google.com>
---
 crypto/async_tx/async_pq.c  | 18 ++++++++++++++----
 crypto/async_tx/raid6test.c |  8 +++++++-
 2 files changed, 21 insertions(+), 5 deletions(-)

Comments

Kees Cook May 3, 2018, 11:32 p.m. UTC | #1 
On Thu, May 3, 2018 at 3:57 PM, Kyle Spiers <ksspiers@google.com> 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 <ksspiers@google.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

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(&submit, 0, NULL, NULL, NULL, addr_conv);
>                         tx = async_gen_syndrome(ptrs, 0, disks, bytes, &submit);
>                 } 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(&submit, 0, tx, NULL, NULL, addr_conv);
>                         tx = async_gen_syndrome(ptrs, 0, disks, bytes, &submit);
> +                       kfree(blocks);
>                 }
>         } else {
>                 if (failb == disks-2) {
> --
> 2.17.0.441.gb46fe60e1d-goog
>
kernel test robot May 4, 2018, 6:25 p.m. UTC | #2 
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(&submit, 0, NULL, NULL, NULL, addr_conv);
    82				tx = async_gen_syndrome(ptrs, 0, disks, bytes, &submit);
    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(&submit, ASYNC_TX_XOR_ZERO_DST, NULL,
   104						  NULL, NULL, addr_conv);
   105				tx = async_xor(dest, blocks, 0, count, bytes, &submit);
   106	
   107				init_async_submit(&submit, 0, tx, NULL, NULL, addr_conv);
   108				tx = async_gen_syndrome(ptrs, 0, disks, bytes, &submit);
 > 109				kfree(blocks);
   110			}
   111		} else {
   112			if (failb == disks-2) {
   113				/* data+P failure. */
   114				init_async_submit(&submit, 0, NULL, NULL, NULL, addr_conv);
   115				tx = async_raid6_datap_recov(disks, bytes, faila, ptrs, &submit);
   116			} else {
   117				/* data+data failure. */
   118				init_async_submit(&submit, 0, NULL, NULL, NULL, addr_conv);
   119				tx = async_raid6_2data_recov(disks, bytes, faila, failb, ptrs, &submit);
   120			}
   121		}
   122		init_completion(&cmp);
   123		init_async_submit(&submit, ASYNC_TX_ACK, tx, callback, &cmp, addr_conv);
   124		tx = async_syndrome_val(ptrs, 0, disks, bytes, &result, spare, &submit);
   125		async_tx_issue_pending(tx);
   126	
   127		if (wait_for_completion_timeout(&cmp, msecs_to_jiffies(3000)) == 0)
   128			pr("%s: timeout! (faila: %d failb: %d disks: %d)\n",
   129			   __func__, faila, failb, disks);
   130	
   131		if (result != 0)
   132			pr("%s: validation failure! faila: %d failb: %d sum_check_flags: %x\n",
   133			   __func__, faila, failb, result);
   134	}
   135	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
diff mbox

Patch

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(&submit, 0, NULL, NULL, NULL, addr_conv);
 			tx = async_gen_syndrome(ptrs, 0, disks, bytes, &submit);
 		} 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(&submit, 0, tx, NULL, NULL, addr_conv);
 			tx = async_gen_syndrome(ptrs, 0, disks, bytes, &submit);
+			kfree(blocks);
 		}
 	} else {
 		if (failb == disks-2) {