From ebb0f38bb47f74b29e267babdbcd2c47d5292aa8 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 6 Mar 2025 07:53:25 -1000 Subject: [PATCH] fs/pipe: fix pipe buffer index use in FUSE This was another case that Rasmus pointed out where the direct access to the pipe head and tail pointers broke on 32-bit configurations due to the type changes. As with the pipe FIONREAD case, fix it by using the appropriate helper functions that deal with the right pipe index sizing. Reported-by: Rasmus Villemoes Link: https://lore.kernel.org/all/878qpi5wz4.fsf@prevas.dk/ Fixes: 3d252160b818 ("fs/pipe: Read pipe->{head,tail} atomically outside pipe->mutex")Cc: Oleg > Cc: Mateusz Guzik Cc: K Prateek Nayak Cc: Swapnil Sapkal Signed-off-by: Linus Torvalds --- fs/fuse/dev.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 2b2d1b7555444..3c9caafca9e29 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -2107,7 +2107,7 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, struct file *out, loff_t *ppos, size_t len, unsigned int flags) { - unsigned int head, tail, mask, count; + unsigned int head, tail, count; unsigned nbuf; unsigned idx; struct pipe_buffer *bufs; @@ -2124,8 +2124,7 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, head = pipe->head; tail = pipe->tail; - mask = pipe->ring_size - 1; - count = head - tail; + count = pipe_occupancy(head, tail); bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL); if (!bufs) { @@ -2135,8 +2134,8 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, nbuf = 0; rem = 0; - for (idx = tail; idx != head && rem < len; idx++) - rem += pipe->bufs[idx & mask].len; + for (idx = tail; !pipe_empty(head, idx) && rem < len; idx++) + rem += pipe_buf(pipe, idx)->len; ret = -EINVAL; if (rem < len) @@ -2147,10 +2146,10 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, struct pipe_buffer *ibuf; struct pipe_buffer *obuf; - if (WARN_ON(nbuf >= count || tail == head)) + if (WARN_ON(nbuf >= count || pipe_empty(head, tail))) goto out_free; - ibuf = &pipe->bufs[tail & mask]; + ibuf = pipe_buf(pipe, tail); obuf = &bufs[nbuf]; if (rem >= ibuf->len) { -- 2.39.5