CVE-2026-31467

Summary

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.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/d6565ea662e17d45a577184b0011bd69de22dc2b
• https://git.kernel.org/stable/c/d9d8360cb66e3b599d89d2526e7da8b530ebf2ff
• https://git.kernel.org/stable/c/5c8ecdcfbfb0b0c6a82a4ebadc1ddea61609b902
• https://git.kernel.org/stable/c/378949f46e897204384f3f5f91e42e93e3f87568
• https://git.kernel.org/stable/c/da40464064599eefe78749f75cd2bba371044c04
• https://git.kernel.org/stable/c/e83e20b82859f0588e9a52a6fa9fea704a2061cf
• https://git.kernel.org/stable/c/c23df30915f83e7257c8625b690a1cece94142a0

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