CVE-2026-89710

Summary

In the Linux kernel, the following vulnerability has been resolved:

NFSv4.1: fix layout segment leak on the pnfs_layout_process() forget path

When the server returns a new layout stateid while a valid one is still held, pnfs_layout_process() calls pnfs_mark_matching_lsegs_return() on the on-stack free_me list and jumps to out_forget. Segments whose reference count drops to zero are unlinked from lo->plh_segs and moved to free_me by mark_lseg_invalid(); for an idle cached segment the layout header holds the only reference, so this happens on the first decrement.

out_forget never drains free_me – only the success path calls pnfs_free_lseg_list().

Commit 814b84971388 ("pNFS/NFSv4: Fix a layout segment leak in pnfs_layout_process()") added the drain; commit 08bd8dbe8882 ("pNFS/NFSv4: Try to return invalid layout in pnfs_layout_process()") removed it while switching the destination to lo->plh_return_segs, which is drained elsewhere. Commit fb700ef02676 ("NFSv4.1: Simplify layout return in pnfs_layout_process()") switched the destination back to free_me without restoring the drain.

Restore the pnfs_free_lseg_list() call.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/7c5b0e813efd9124760d5fd1bfc6b229f03fb1a2
• https://git.kernel.org/stable/c/36e3f13bf0728f4ce11ee8904cec82a783222f62
• https://git.kernel.org/stable/c/32ac1b0b7f1cfa0d1a1faf9c72f4154046101070
• https://git.kernel.org/stable/c/ee5a386cfe60f3f8286de16a9db8e1a08f0bc124

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