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authorJens Axboe <axboe@kernel.dk>2026-03-19 14:29:09 -0600
committerJens Axboe <axboe@kernel.dk>2026-03-19 15:09:40 -0600
commit3ecd3e03144b38a21a3b70254f1b9d2e16629b09 (patch)
treef22e192299277974691d60645d808aeb4f84d6b6 /io_uring
parenta68ed2df72131447d131531a08fe4dfcf4fa4653 (diff)
io_uring/kbuf: fix missing BUF_MORE for incremental buffers at EOF
For a zero length transfer, io_kbuf_inc_commit() is called with !len. Since we never enter the while loop to consume the buffers, io_kbuf_inc_commit() ends up returning true, consuming the buffer. But if no data was consumed, by definition it cannot have consumed the buffer. Return false for that case. Reported-by: Martin Michaelis <code@mgjm.de> Cc: stable@vger.kernel.org Fixes: ae98dbf43d75 ("io_uring/kbuf: add support for incremental buffer consumption") Link: https://github.com/axboe/liburing/issues/1553 Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
-rw-r--r--io_uring/kbuf.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index e7f444953dfb..a4cb6752b7aa 100644
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -34,6 +34,10 @@ struct io_provide_buf {
static bool io_kbuf_inc_commit(struct io_buffer_list *bl, int len)
{
+ /* No data consumed, return false early to avoid consuming the buffer */
+ if (!len)
+ return false;
+
while (len) {
struct io_uring_buf *buf;
u32 buf_len, this_len;