On Wed, Dec 04, 2019 at 07:27:44PM +0100, Vlastimil Babka wrote:
On 12/4/19 6:56 PM, Greg Kroah-Hartman wrote:
From: Vlastimil Babka vbabka@suse.cz
The mainline commit 8fde12ca79af ("mm: prevent get_user_pages() from overflowing page refcount") was backported to 4.9.y stable as commit 2ed768cfd895. The backport however missed that in 4.9, there are several arch-specific gup.c versions with fast gup implementations, so these do not prevent refcount overflow.
This is partially fixed for x86 in stable-only commit d73af79742e7 ("x86, mm, gup: prevent get_page() race with munmap in paravirt guest"). This stable-only commit adds missing parts to x86 version, as well as s390 version, both taken from the SUSE SLES/openSUSE 4.12-based kernels.
The remaining architectures with own gup.c are sparc, mips, sh. It's unlikely the known overflow scenario based on FUSE, which needs 140GB of RAM, is a problem for those architectures, and I don't feel confident enough to patch them.
Signed-off-by: Vlastimil Babka vbabka@suse.cz Signed-off-by: Sasha Levin sashal@kernel.org
No, this one had a leak bug and I've sent updated version: https://lore.kernel.org/linux-mm/e274291b-054f-2fad-28e8-59fabf312e61@suse.c...
Ugh. Ok, let me go fix that up...