CVE-2026-80855fuse: fix invalidate lock leak on open O_TRUNC DAX failure

Official description

In the Linux kernel, the following vulnerability has been resolved: fuse: fix invalidate lock leak on open O_TRUNC DAX failure fuse_open() takes filemap_invalidate_lock() for a DAX truncate (dax_truncate = true) and releases it before the out_inode_unlock label. But when fuse_dax_break_layouts() fails, the goto out_inode_unlock skips the unlock and leaks the rwsem, so any later fault or truncate on the file stalls on the stale lock. fuse_dax_break_layouts() can fail with -ERESTARTSYS when a signal interrupts the wait for busy DAX pages to drain: open("file", O_RDWR | O_TRUNC) └─ fuse_open() ├─ filemap_invalidate_lock() # dax_truncate └─ fuse_dax_break_layouts() └─ dax_break_layout() └─ wait_page_idle() # TASK_INTERRUPTIBLE └─ fuse_wait_dax_page() # unlock, schedule, re-lock └─ signal → -ERESTARTSYS goto out_inode_unlock # <- lock leaked Fix this by moving filemap_invalidate_unlock() below the label so that all error paths release the lock, and rename the label to out_unlock as it now covers more than just the inode lock.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/69a294e561c10909688bcb25456535dcd1818e1a
• https://git.kernel.org/stable/c/1b04d80a27d317064cce2307472f5bef9975bc50
• https://git.kernel.org/stable/c/a61524da59a2f5ac9c8de23ff98b30da769ab144
• https://git.kernel.org/stable/c/dcf30a56624c2a0cfab1bada5b1ca8cc0c02f010
• https://git.kernel.org/stable/c/7288c279ddbd654a06c82118c1a3f5570c1807f0
• https://git.kernel.org/stable/c/776e85fda752f9a15e0f82dec42ecacd12a9bd94
• https://git.kernel.org/stable/c/1d3e701cda2f41d48aa721b3ebefbe0fbf8d74da
• https://git.kernel.org/stable/c/e981474d7bf1457da12404e169ea147d2c8ecea7
• https://git.kernel.org/stable/c/a927f1867e61b78f39f9da0bbba3c98c2ca151fe