CVE-2026-98223
Description
AI Translation Available
In the Linux kernel, the following vulnerability has been resolved:
mm: filemap: retain mapped dropbehind folios
Fault-around can map ready dropbehind folios without going through the
normal page-cache lookup that clears dropbehind. A mapping represents a
competing cached user, so retain the folio instead of forcibly unmapping
it when writeback completes.
For a mapped folio, folio_unmap_invalidate() can call
unmap_mapping_folio(), which takes i_mmap_rwsem and may sleep. Retaining
mapped folios avoids this path when folio_end_dropbehind() runs in
non-preemptible task context.
Tal was able to trigger a sleeping-in-atomic warning due to this [1].
Unmapped dropbehind folios continue through the existing invalidation path.
https://git.kernel.org/stable/c/2897601dffe576fcd87a4259102f41f7fb0cbfc8
https://git.kernel.org/stable/c/77c0fade37c80e8aa16ac048a9828249055e3f66
https://git.kernel.org/stable/c/848d2ce2fce15fbdc083fbf9691bfa72911033c4