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fs/pipe: fix pipe buffer index use in FUSE

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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 <ravi@prevas.dk>
Link: https://lore.kernel.org/all/878qpi5wz4.fsf@prevas.dk/
Fixes: 3d252160b8 ("fs/pipe: Read pipe->{head,tail} atomically outside pipe->mutex")Cc: Oleg >
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Swapnil Sapkal <swapnil.sapkal@amd.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2025-03-06 07:53:25 -10:00
parent d810d4c27b
commit ebb0f38bb4
1 changed files with 6 additions and 7 deletions
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13
fs/fuse/dev.c
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@ -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) {