diff options
| author | Qi Zheng <zhengqi.arch@bytedance.com> | 2022-07-26 09:24:36 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-07-26 19:21:43 +0300 |
| commit | cdb281e63874086a650552d36c504ea717a0e0cb (patch) | |
| tree | 22d312d4d3875c486bdd61311d36a116fada06be /mm/hugetlb.c | |
| parent | e0dccc3b76fb35bb257b4118367a883073d7390e (diff) | |
mm: fix NULL pointer dereference in wp_page_reuse()
The vmf->page can be NULL when the wp_page_reuse() is invoked by
wp_pfn_shared(), it will cause the following panic:
BUG: kernel NULL pointer dereference, address: 000000000000008
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 18 PID: 923 Comm: Xorg Not tainted 5.19.0-rc8.bm.1-amd64 #263
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g14
RIP: 0010:_compound_head+0x0/0x40
[...]
Call Trace:
wp_page_reuse+0x1c/0xa0
do_wp_page+0x1a5/0x3f0
__handle_mm_fault+0x8cf/0xd20
handle_mm_fault+0xd5/0x2a0
do_user_addr_fault+0x1d0/0x680
exc_page_fault+0x78/0x170
asm_exc_page_fault+0x22/0x30
To fix it, this patch performs a NULL pointer check before dereferencing
the vmf->page.
Fixes: 6c287605fd56 ("mm: remember exclusively mapped anonymous pages with PG_anon_exclusive")
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
0 files changed, 0 insertions, 0 deletions