CVE-2026-93075

Summary

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

dax/fsdev: clear pgmap ops and owner on unbind

fsdev_dax_probe() sets pgmap->ops = &fsdev_pagemap_ops and pgmap->owner = dev_dax, but nothing ever clears them. For a dynamic device the pgmap is devm-allocated and freed on unbind, so this is harmless. For a static device the pgmap is the shared, long-lived one owned by the dax bus (kill_dev_dax() only NULLs dev_dax->pgmap for the non-static case), and device.c's probe sets only pgmap->type, never clearing ops/owner.

So after fsdev unbinds a static device the stale fsdev_pagemap_ops survives on the shared pgmap. If the device is then rebound to device_dax (MEMORY_DEVICE_GENERIC, which installs no ->memory_failure), or the fsdev_dax module is unloaded, a subsequent memory_failure on that pgmap dispatches through the stale – and possibly freed – handler.

Register a devm action that clears pgmap->ops and pgmap->owner on unbind, symmetric with setting them at probe, so the pgmap carries no fsdev state once fsdev is detached.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/9b0f91dc9147a8601cec3d4d83cf13c6aaf71b27
• https://git.kernel.org/stable/c/f48884ac31b6bfc99f36b3f207b8c0cbe5d54bd7

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