ntfs3: fix circular locking dependency in run_unpack_ex

Summary

In the Linux kernel, the following vulnerability has been resolved: ntfs3: fix circular locking dependency in run_unpack_ex Syzbot reported a circular locking dependency between wnd->rw_lock (sbi->used.bitmap) and ni->file.run_lock. The deadlock scenario: 1. ntfs_extend_mft() takes ni->file.run_lock then wnd->rw_lock. 2. run_unpack_ex() takes wnd->rw_lock then tries to acquire ni->file.run_lock inside ntfs_refresh_zone(). This creates an AB-BA deadlock. Fix this by using down_read_trylock() instead of down_read() when acquiring run_lock in run_unpack_ex(). If the lock is contended, skip ntfs_refresh_zone() - the MFT zone will be refreshed on the next MFT operation. This breaks the circular dependency since we never block waiting for run_lock while holding wnd->rw_lock.

Timeline

1. May 6, 2026, 11:27 AM UTCCVE published
2. Oct 21, 2026, 12:40 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 57f7979aefdcef66326bda47e07ee0d8be64bf21 · fixed in d60f09d2d16c44a797d8cb67015cde2508720506; From db7fc56646cafe39599a4c21f1398e2bdfd5c185 · fixed in 76016d15bbd90caa0ce7765fddf9bde8e943e601; From 5fc982fe7eca9d0cf7b25832450ebd4f7c8e1c36 · fixed in b014372b62237521444ee51384549bdf48b79015; From 5fc982fe7eca9d0cf7b25832450ebd4f7c8e1c36 · fixed in b8d22d9d8260b0f4f4d8e2898c98037c9982ea66; From 5fc982fe7eca9d0cf7b25832450ebd4f7c8e1c36 · fixed in 08ce2fee1b869ecbfbd94e0eb2630e52203a2e03; From 6.6.66 · fixed in 6.6.160; From 6.12.5 · fixed in 6.12.114

• Linux Linux

  6.13

• KernelLinux

  fixed in 6.6.160; From 6.7.0 · fixed in 6.12.114; From 6.13.0 · fixed in 6.18.16; fixed in 6.19.6

References 5