Re: [PATCH] fs: aio: reject partial mremap to avoid Null-pointer-dereference error

[Christian Brauner]

On Sat, 18 Apr 2026 14:06:34 +0800, Zizhi Wo wrote:
> [BUG]
> Recently, our internal syzkaller testing uncovered a null pointer
> dereference issue:
> BUG: kernel NULL pointer dereference, address: 0000000000000000
> ...
> [   51.111664]  filemap_read_folio+0x25/0xe0
> [   51.112410]  filemap_fault+0xad7/0x1250
> [   51.113112]  __do_fault+0x4b/0x460
> [   51.113699]  do_pte_missing+0x5bc/0x1db0
> [   51.114250]  ? __pte_offset_map+0x23/0x170
> [   51.114822]  __handle_mm_fault+0x9f8/0x1680
> ...
> Crash analysis showed the file involved was an AIO ring file. The
> phenomenon triggered is the same as the issue described in [1].
> 
> [...]

Applied to the vfs.fixes branch of the vfs/vfs.git tree.
Patches in the vfs.fixes branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.fixes

[1/1] fs: aio: reject partial mremap to avoid Null-pointer-dereference error
      https://git.kernel.org/vfs/vfs/c/db80e11b54d2