dax: read holder_ops once in dax_holder_notify_failure()

Summary

In the Linux kernel, the following vulnerability has been resolved: dax: read holder_ops once in dax_holder_notify_failure() dax_holder_notify_failure() reads dax_dev->holder_ops twice without READ_ONCE() -- once for the NULL check and once for the indirect notify_failure() call. A concurrent fs_put_dax() can clear holder_ops between the two reads, so the check can observe a non-NULL pointer while the call dereferences NULL. (kill_dax() also clears holder_ops, but only after synchronize_srcu(), so it cannot race a reader that is inside dax_read_lock(); fs_put_dax() does no such synchronization.) Fetch holder_ops once into a local with READ_ONCE() so the NULL check and the indirect call observe the same value.

Timeline

1. Sep 17, 2026, 4:10 PM UTCCVE published
2. Oct 19, 2026, 9:05 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 8012b866085523758780850087102421dbcce522 · fixed in 1661b9bf78def01a8c96409569772d9b2592f4ba; From 8012b866085523758780850087102421dbcce522 · fixed in 0a42180d5410c98829ee72d1d426fb7faf9e6873; From 8012b866085523758780850087102421dbcce522 · fixed in ee1251621d1c7cf3155c6704542cbb358d799968; From 8012b866085523758780850087102421dbcce522 · fixed in 6a37acecc7c29136235cbc446a1b89e81414344b; From 8012b866085523758780850087102421dbcce522 · fixed in eb412f80311fc7ab6eb3203091a3fe59a5e9fd30; From 8012b866085523758780850087102421dbcce522 · fixed in 7ae9d15bdcde0f2955ae13b6a95587f9e23b2359

• Linux Linux

  6.0

• KernelLinux

  From 6.0.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.110; From 6.13.0 · fixed in 6.18.52; From 6.19.0 · fixed in 7.2.6

References 6