There's a fix for this already in the for-next branch: https://github.com/btrfs/linux/commit/1a287050962c6847fa4918d6b2a0f4cee35c6943 On 17/12/24 22:58, Mirsad Todorovac wrote: > > > The static analyser tool gave the following advice: > > ./fs/btrfs/ioctl.c:4987:9-16: WARNING opportunity for kmemdup > > 4986 if (!iov) { > → 4987 iov = kmalloc(sizeof(struct iovec) * args.iovcnt, GFP_NOFS); > 4988 if (!iov) { > 4989 unlock_extent(io_tree, start, lockend, &cached_state); > 4990 btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED); > 4991 ret = -ENOMEM; > 4992 goto out_acct; > 4993 } > 4994 > → 4995 memcpy(iov, iovstack, sizeof(struct iovec) * args.iovcnt); > 4996 } > > Replacing kmalloc() + memcpy() with kmemdump() doesn't change semantics. > Original code works without fault, so this is not a bug fix but proposed improvement. > > Link: https://urldefense.com/v3/__https://lwn.net/Articles/198928/__;!!Bt8RZUm9aw!4OVzQmIUbyH-UGdUwMAL582hR4Q-7HN2fn9IpyxeA1T8qrcC8RdBVz4xuL4m35_kksUllAi6OmdbRehcFpwfHw$ > Fixes: 34310c442e175 ("btrfs: add io_uring command for encoded reads (ENCODED_READ ioctl)") > Cc: Chris Mason <clm@xxxxxx> > Cc: Josef Bacik <josef@xxxxxxxxxxxxxx> > Cc: David Sterba <dsterba@xxxxxxxx> > Cc: linux-btrfs@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Signed-off-by: Mirsad Todorovac <mtodorovac69@xxxxxxxxx> > --- > v1: > initial version. > > fs/btrfs/ioctl.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > index 3af8bb0c8d75..c2f769334d3c 100644 > --- a/fs/btrfs/ioctl.c > +++ b/fs/btrfs/ioctl.c > @@ -4984,15 +4984,13 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue > * undo this. > */ > if (!iov) { > - iov = kmalloc(sizeof(struct iovec) * args.iovcnt, GFP_NOFS); > + iov = kmemdup(iovstack, sizeof(struct iovec) * args.iovcnt, GFP_NOFS); > if (!iov) { > unlock_extent(io_tree, start, lockend, &cached_state); > btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED); > ret = -ENOMEM; > goto out_acct; > } > - > - memcpy(iov, iovstack, sizeof(struct iovec) * args.iovcnt); > } > > count = min_t(u64, iov_iter_count(&iter), disk_io_size);
