* [PATCH] hugetlbfs: avoid overflow in hugetlbfs_fallocate
@ 2021-11-24 4:08 yangerkun
2021-11-24 4:24 ` Matthew Wilcox
0 siblings, 1 reply; 3+ messages in thread
From: yangerkun @ 2021-11-24 4:08 UTC (permalink / raw)
To: mike.kravetz, willy; +Cc: linux-mm, linux-fsdevel, yukuai3, yangerkun
luojiajun report a problem[1] two years ago which seems still exists in
mainline. vfs_fallocate can avoid 'offset + len' trigger overflow, but
'offset + len + hpage_size - 1' may overflow too and will lead to a
wrong 'end'. luojiajun give a solution which can fix the wrong 'end'
but leave the overflow still happened. We should fix it by transfer
'offset' to unsigned long long.
[1] https://patchwork.kernel.org/project/linux-mm/patch/1554775226-67213-1-git-send-email-luojiajun3@huawei.com/
Signed-off-by: yangerkun <yangerkun@huawei.com>
---
fs/hugetlbfs/inode.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 49d2e686be74..8012a14901de 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -651,7 +651,8 @@ static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
* as well as being converted to page offsets.
*/
start = offset >> hpage_shift;
- end = (offset + len + hpage_size - 1) >> hpage_shift;
+ end = ((unsigned long long)offset + len + hpage_size - 1)
+ >> hpage_shift;
inode_lock(inode);
--
2.31.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] hugetlbfs: avoid overflow in hugetlbfs_fallocate
2021-11-24 4:08 [PATCH] hugetlbfs: avoid overflow in hugetlbfs_fallocate yangerkun
@ 2021-11-24 4:24 ` Matthew Wilcox
2021-11-24 6:05 ` yangerkun
0 siblings, 1 reply; 3+ messages in thread
From: Matthew Wilcox @ 2021-11-24 4:24 UTC (permalink / raw)
To: yangerkun; +Cc: mike.kravetz, linux-mm, linux-fsdevel, yukuai3
On Wed, Nov 24, 2021 at 12:08:18PM +0800, yangerkun wrote:
> start = offset >> hpage_shift;
> - end = (offset + len + hpage_size - 1) >> hpage_shift;
> + end = ((unsigned long long)offset + len + hpage_size - 1)
> + >> hpage_shift;
+ end = DIV_ROUND_UP_ULL(offset + len, hpage_size);
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] hugetlbfs: avoid overflow in hugetlbfs_fallocate
2021-11-24 4:24 ` Matthew Wilcox
@ 2021-11-24 6:05 ` yangerkun
0 siblings, 0 replies; 3+ messages in thread
From: yangerkun @ 2021-11-24 6:05 UTC (permalink / raw)
To: Matthew Wilcox; +Cc: mike.kravetz, linux-mm, linux-fsdevel, yukuai3
On 2021/11/24 12:24, Matthew Wilcox wrote:
> On Wed, Nov 24, 2021 at 12:08:18PM +0800, yangerkun wrote:
>> start = offset >> hpage_shift;
>> - end = (offset + len + hpage_size - 1) >> hpage_shift;
>> + end = ((unsigned long long)offset + len + hpage_size - 1)
>> + >> hpage_shift;
>
> + end = DIV_ROUND_UP_ULL(offset + len, hpage_size);
Thanks, will do it in v2!
> .
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-11-24 4:08 [PATCH] hugetlbfs: avoid overflow in hugetlbfs_fallocate yangerkun
2021-11-24 4:24 ` Matthew Wilcox
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