CVE-2026-98388exec: do_close_on_exec() before taking exec_update_lock

Official description

In the Linux kernel, the following vulnerability has been resolved: exec: do_close_on_exec() before taking exec_update_lock do_close_on_exec() currently happens while holding the exec_update_lock, which is used in a lot of places that access process state to synchronize access checks. I recently added another such use of exec_update_lock, causing a regression. do_close_on_exec() can block waiting for a reply from a filesystem. That means a hung filesystem can block codepaths that use exec_update_lock; and it also means that a FUSE filesystem which attempts to inspect the calling process can deadlock. To avoid such problems, move do_close_on_exec() before the exec_update_lock is taken, but after the FD table has been copied if necessary. I have looked through all the calls between the old and new position of the do_close_on_exec() call; there seems to be no file descriptor table access in between.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/955973fff4a36d39a848b00cac1706863f568fe1
• https://git.kernel.org/stable/c/550feab5b01000ab314868b62211fb3ddfd600e8
• https://git.kernel.org/stable/c/5aacc19ba2b1faf84c4a2f2cf9a1784e03d1ff38
• https://git.kernel.org/stable/c/3feb4020bfb7ccf0d347f27051639d25e19cd65d
• https://git.kernel.org/stable/c/0d86cd6b709c39216e6ee5ea8f0fc4242bbb2b53
• https://git.kernel.org/stable/c/19ddef61ee0a49782a60f8f497e50597ad5de2da
• https://git.kernel.org/stable/c/63be3d8511bdafa095cd14a393cbf3c58dbbb928
• https://git.kernel.org/stable/c/e780259b54e618ceb4763fbc21314acf3565e813