dm: writecache: Use 2-factor allocator arguments

PATCH In review Kees Cook 3 participants 6 messages Jun 18, 2018 – Jun 27, 2018 Device mapper

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Kees Cook

author

2018-06-18 17:50 UTC #0 lore raw

PATCH 1/1 dm: writecache: Use 2-factor allocator arguments

This adjusts the allocator calls to use the 2-factor argument style, as already done treewide for better defense against allocator overflows. Additionally adjusts style nit to avoid assignments in test expressions.

Signed-off-by Kees Cook <[email protected]>

---
 drivers/md/dm-writecache.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

drivers/md/dm-writecache.c +10 -6

index 5961c7794ef3..7773f4c75701 100644
@@ -259,7 +259,7 @@ static int persistent_memory_claim(struct dm_writecache *wc)
 	if (da != p) {
 		long i;
 		wc->memory_map = NULL;
-		pages = kvmalloc(p * sizeof(struct page *), GFP_KERNEL);
+		pages = kvmalloc_array(p, sizeof(struct page *), GFP_KERNEL);
 		if (!pages) {
 			r = -ENOMEM;
 			goto err2;

@@ -859,7 +859,8 @@ static int writecache_alloc_entries(struct dm_writecache *wc)
 
 	if (wc->entries)
 		return 0;
-	wc->entries = vmalloc(sizeof(struct wc_entry) * wc->n_blocks);
+	wc->entries = vmalloc(array_size(sizeof(struct wc_entry),
+					 wc->n_blocks));
 	if (!wc->entries)
 		return -ENOMEM;
 	for (b = 0; b < wc->n_blocks; b++) {

@@ -1480,10 +1481,13 @@ static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeba
 		bio_set_dev(&wb->bio, wc->dev->bdev);
 		wb->bio.bi_iter.bi_sector = read_original_sector(wc, e);
 		wb->page_offset = PAGE_SIZE;
-		if (max_pages <= WB_LIST_INLINE ||
-		    unlikely(!(wb->wc_list = kmalloc(max_pages * sizeof(struct wc_entry *),
-						     GFP_NOIO | __GFP_NORETRY |
-						     __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
+		if (max_pages > WB_LIST_INLINE)
+			wb->wc_list = kmalloc_array(max_pages,
+						    sizeof(struct wc_entry *),
+						    GFP_NOIO | __GFP_NORETRY |
+						    __GFP_NOMEMALLOC |
+						    __GFP_NOWARN);
+		if (max_pages <= WB_LIST_INLINE || !wb->wc_list) {
 			wb->wc_list = wb->wc_list_inline;
 			max_pages = WB_LIST_INLINE;
 		}

Signature · 6 lines

2.17.0


-- 
Kees Cook
Pixel Security

Mikulas Patocka

maintainer

2018-06-18 21:12 UTC #1 lore raw

Quoted 37 lines · Kees Cook

Signed-off-by Kees Cook <[email protected]>

---
 drivers/md/dm-writecache.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

drivers/md/dm-writecache.c +3 -3

index 5961c7794ef3..7773f4c75701 100644
@@ -259,7 +259,7 @@ static int persistent_memory_claim(struct dm_writecache *wc)
 	if (da != p) {
 		long i;
 		wc->memory_map = NULL;
-		pages = kvmalloc(p * sizeof(struct page *), GFP_KERNEL);
+		pages = kvmalloc_array(p, sizeof(struct page *), GFP_KERNEL);
 		if (!pages) {
 			r = -ENOMEM;
 			goto err2;

@@ -859,7 +859,8 @@ static int writecache_alloc_entries(struct dm_writecache *wc)
 
 	if (wc->entries)
 		return 0;
-	wc->entries = vmalloc(sizeof(struct wc_entry) * wc->n_blocks);
+	wc->entries = vmalloc(array_size(sizeof(struct wc_entry),
+					 wc->n_blocks));
 	if (!wc->entries)
 		return -ENOMEM;
 	for (b = 0; b < wc->n_blocks; b++) {

@@ -1480,10 +1481,13 @@ static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeba
 		bio_set_dev(&wb->bio, wc->dev->bdev);
 		wb->bio.bi_iter.bi_sector = read_original_sector(wc, e);
 		wb->page_offset = PAGE_SIZE;
-		if (max_pages <= WB_LIST_INLINE ||

drivers/md/dm-writecache.c static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeba · line 1490

Quoted 10 lines

drivers/md/dm-writecache.c +7 -3

-		    unlikely(!(wb->wc_list = kmalloc(max_pages * sizeof(struct wc_entry *),
-						     GFP_NOIO | __GFP_NORETRY |
-						     __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
+		if (max_pages > WB_LIST_INLINE)
+			wb->wc_list = kmalloc_array(max_pages,
+						    sizeof(struct wc_entry *),
+						    GFP_NOIO | __GFP_NORETRY |
+						    __GFP_NOMEMALLOC |
+						    __GFP_NOWARN);
+		if (max_pages <= WB_LIST_INLINE || !wb->wc_list) {

The rest of patch is OK - but you shouldn't duplicate the comparison against WB_LIST_INLINE.

Mikulas

Quoted 11 lines

drivers/md/dm-writecache.c +0 -0

 			wb->wc_list = wb->wc_list_inline;
 			max_pages = WB_LIST_INLINE;
 		}

Signature · 6 lines

2.17.0


-- 
Kees Cook
Pixel Security

Kees Cook

author

2018-06-18 22:10 UTC #2 lore raw

Quoted 46 lines · Mikulas Patocka

Quoted 42 lines · Kees Cook

Signed-off-by Kees Cook <[email protected]>

---
 drivers/md/dm-writecache.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

drivers/md/dm-writecache.c +5 -6

index 5961c7794ef3..7773f4c75701 100644
@@ -259,7 +259,7 @@ static int persistent_memory_claim(struct dm_writecache *wc)
      if (da != p) {
              long i;
              wc->memory_map = NULL;
-             pages = kvmalloc(p * sizeof(struct page *), GFP_KERNEL);
+             pages = kvmalloc_array(p, sizeof(struct page *), GFP_KERNEL);
              if (!pages) {
                      r = -ENOMEM;
                      goto err2;

@@ -859,7 +859,8 @@ static int writecache_alloc_entries(struct dm_writecache *wc)
 
      if (wc->entries)
              return 0;
-     wc->entries = vmalloc(sizeof(struct wc_entry) * wc->n_blocks);
+     wc->entries = vmalloc(array_size(sizeof(struct wc_entry),
+                                      wc->n_blocks));
      if (!wc->entries)
              return -ENOMEM;
      for (b = 0; b < wc->n_blocks; b++) {

@@ -1480,10 +1481,13 @@ static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeba
              bio_set_dev(&wb->bio, wc->dev->bdev);
              wb->bio.bi_iter.bi_sector = read_original_sector(wc, e);
              wb->page_offset = PAGE_SIZE;
-             if (max_pages <= WB_LIST_INLINE ||
-                 unlikely(!(wb->wc_list = kmalloc(max_pages * sizeof(struct wc_entry *),
-                                                  GFP_NOIO | __GFP_NORETRY |
-                                                  __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
+             if (max_pages > WB_LIST_INLINE)
+                     wb->wc_list = kmalloc_array(max_pages,

Quoted 8 lines

drivers/md/dm-writecache.c static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeba · line 1490

Quoted 5 lines

drivers/md/dm-writecache.c +5 -0

+                                                 sizeof(struct wc_entry *),
+                                                 GFP_NOIO | __GFP_NORETRY |
+                                                 __GFP_NOMEMALLOC |
+                                                 __GFP_NOWARN);
+             if (max_pages <= WB_LIST_INLINE || !wb->wc_list) {

The rest of patch is OK - but you shouldn't duplicate the comparison against WB_LIST_INLINE.

I couldn't find a better way to avoid an assignment in a test... open to suggestions! :)

-Kees

Signature · 2 lines

Kees Cook
Pixel Security

Kees Cook

author

2018-06-27 21:48 UTC #3 lore raw

In reply to Kees Cook

Quoted 5 lines · Kees Cook

This adjusts the allocator calls to use the 2-factor argument style, as already done treewide for better defense against allocator overflows. Additionally adjusts style nit to avoid assignments in test expressions.
Signed-off-by Kees Cook <[email protected]>

Friendly ping -- I'd like to make sure this makes it into 4.18. All other 2-factor allocations have been fixed in the kernel.

-Kees

Quoted 52 lines

---
 drivers/md/dm-writecache.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

drivers/md/dm-writecache.c +10 -7

index 5961c7794ef3..7773f4c75701 100644
@@ -259,7 +259,7 @@ static int persistent_memory_claim(struct dm_writecache *wc)
        if (da != p) {
                long i;
                wc->memory_map = NULL;
-               pages = kvmalloc(p * sizeof(struct page *), GFP_KERNEL);
+               pages = kvmalloc_array(p, sizeof(struct page *), GFP_KERNEL);
                if (!pages) {
                        r = -ENOMEM;
                        goto err2;

@@ -859,7 +859,8 @@ static int writecache_alloc_entries(struct dm_writecache *wc)
 
        if (wc->entries)
                return 0;
-       wc->entries = vmalloc(sizeof(struct wc_entry) * wc->n_blocks);
+       wc->entries = vmalloc(array_size(sizeof(struct wc_entry),
+                                        wc->n_blocks));
        if (!wc->entries)
                return -ENOMEM;
        for (b = 0; b < wc->n_blocks; b++) {

@@ -1480,10 +1481,13 @@ static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeba
                bio_set_dev(&wb->bio, wc->dev->bdev);
                wb->bio.bi_iter.bi_sector = read_original_sector(wc, e);
                wb->page_offset = PAGE_SIZE;
-               if (max_pages <= WB_LIST_INLINE ||
-                   unlikely(!(wb->wc_list = kmalloc(max_pages * sizeof(struct wc_entry *),
-                                                    GFP_NOIO | __GFP_NORETRY |
-                                                    __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
+               if (max_pages > WB_LIST_INLINE)
+                       wb->wc_list = kmalloc_array(max_pages,
+                                                   sizeof(struct wc_entry *),
+                                                   GFP_NOIO | __GFP_NORETRY |
+                                                   __GFP_NOMEMALLOC |
+                                                   __GFP_NOWARN);
+               if (max_pages <= WB_LIST_INLINE || !wb->wc_list) {
                        wb->wc_list = wb->wc_list_inline;
                        max_pages = WB_LIST_INLINE;
                }
--

2.17.0

--
Kees Cook
Pixel Security

Signature · 2 lines

Kees Cook
Pixel Security

Mike Snitzer

2018-06-27 21:52 UTC #4 lore raw

Quoted 9 lines · Kees Cook

Quoted 5 lines · Kees Cook
This adjusts the allocator calls to use the 2-factor argument style, as already done treewide for better defense against allocator overflows. Additionally adjusts style nit to avoid assignments in test expressions.
Signed-off-by Kees Cook <[email protected]>
Friendly ping -- I'd like to make sure this makes it into 4.18. All other 2-factor allocations have been fixed in the kernel.

Yeap, I'll be sending it to Linus this week. Already staged and ready to go, please see:
https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-4.18&id=50a7d3ba7c9ac5e0b7e03fc7f420180989361dbf

Thanks,
Mike

Kees Cook

author

2018-06-27 21:53 UTC #5 lore raw

Quoted 8 lines · Mike Snitzer

Quoted 5 lines · Kees Cook
Quoted 4 lines · Kees Cook
This adjusts the allocator calls to use the 2-factor argument style, as already done treewide for better defense against allocator overflows. Additionally adjusts style nit to avoid assignments in test expressions.

Quoted 8 lines

Quoted 4 lines
Quoted 1 line
Signed-off-by Kees Cook <[email protected]>
Friendly ping -- I'd like to make sure this makes it into 4.18. All other 2-factor allocations have been fixed in the kernel.
Yeap, I'll be sending it to Linus this week. Already staged and ready to go, please see:
https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=dm-4.18&id=50a7d3ba7c9ac5e0b7e03fc7f420180989361dbf

Ah! Thank you very much! :)

-Kees

Signature · 2 lines

Kees Cook
Pixel Security