DocumentationOverview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
block: skip sync_blockdev() on surprise removal in bdev_mark_dead()
bdev_mark_dead()’s @surprise == true means the device is already gone. The filesystem callback fs_bdev_mark_dead() honours this and skips sync_filesystem(), but the bare block device path (no ->mark_dead op) lost its !surprise guard when the holder ->mark_dead callback was wired up (see Fixes), and now calls sync_blockdev() unconditionally, which can hang forever waiting on writeback that can no longer complete.
syzkaller hit this via nvme_reset_work()’s “I/O queues lost” path: nvme_mark_namespaces_dead() -> blk_mark_disk_dead() -> bdev_mark_dead(bdev, true) -> sync_blockdev() blocks in folio_wait_writeback(), wedging the reset worker and every task waiting on it.
Skip the sync on surprise removal, matching fs_bdev_mark_dead(); invalidate_bdev() still runs. Orderly removal (surprise == false) is unchanged.
Found by FuzzNvme(Syzkaller with FEMU fuzzing framework).
Details
- Affected product:
- AlmaLinux 9.2 ESU , TuxCare 9.6 ESU , TuxCare 9.8 ESU
- Affected packages:
- kernel @ 5.14.0 (+2 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Debian 13 | Released |
12 kernels
|
| Ubuntu 24.04 | Planned | — |
| Ubuntu 24.04 AWS | Planned | — |
| Ubuntu 26.04 | Will Not Fix | — |