CVE-2026-31467

/// Technical description

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

erofs: add GFP_NOIO in the bio completion if needed

The bio completion path in the process context (e.g. dm-verity)

will directly call into decompression rather than trigger another

workqueue context for minimal scheduling latencies, which can

then call vm_map_ram() with GFP_KERNEL.

Due to insufficient memory, vm_map_ram() may generate memory

swapping I/O, which can cause submit_bio_wait to deadlock

in some scenarios.

Trimmed down the call stack, as follows:

f2fs_submit_read_io

submit_bio //bio_list is initialized.

mmc_blk_mq_recovery

z_erofs_endio

vm_map_ram

__pte_alloc_kernel

__alloc_pages_direct_reclaim

shrink_folio_list

__swap_writepage

submit_bio_wait //bio_list is non-NULL, hang!!!

Use memalloc_noio_{save,restore}() to wrap up this path.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References