CVE-2025-40220
CVE-2025-40220CVE-2025-40220
Description
In the Linux kernel, the following vulnerability has been resolved:
fuse: fix livelock in synchronous file put from fuseblk workers
I observed a hang when running generic/323 against a fuseblk server.
This test opens a file, initiates a lot of AIO writes to that file
descriptor, and closes the file descriptor before the writes complete.
Unsurprisingly, the AIO exerciser threads are mostly stuck waiting for
responses from the fuseblk server:
# cat /proc/372265/task/372313/stack
[<0>] request_wait_answer+0x1fe/0x2a0 [fuse]
[<0>] __fuse_simple_request+0xd3/0x2b0 [fuse]
[<0>] fuse_do_getattr+0xfc/0x1f0 [fuse]
[<0>] fuse_file_read_iter+0xbe/0x1c0 [fuse]
[<0>] aio_read+0x130/0x1e0
[<0>] io_submit_one+0x542/0x860
[<0>] __x64_sys_io_submit+0x98/0x1a0
[<0>] do_syscall_64+0x37/0xf0
[<0>] entry_SYSCALL_64_after_hwframe+0x4b/0x53
But the /weird/ part is that the fuseblk server threads are waiting for
responses from itself:
# cat /proc/372210/task/372232/stack
[<0>] request_wait_answer+0x1fe/0
Scoring
| Last modified | 2026-10-19 |