CVE-2026-31467erofs: add GFP_NOIO in the bio completion if needed

Official 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.

Affected packages & fixed versions

Affected products (as reported)

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