https://github.com/torvalds/linux
Revision cdb281e63874086a650552d36c504ea717a0e0cb authored by Qi Zheng on 26 July 2022, 06:24:36 UTC, committed by Linus Torvalds on 26 July 2022, 16:21:43 UTC
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>
1 parent e0dccc3
Tip revision: cdb281e63874086a650552d36c504ea717a0e0cb authored by Qi Zheng on 26 July 2022, 06:24:36 UTC
mm: fix NULL pointer dereference in wp_page_reuse()
mm: fix NULL pointer dereference in wp_page_reuse()
Tip revision: cdb281e
| File | Mode | Size |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | -rw-r--r-- | 19.8 KB |
| .cocciconfig | -rw-r--r-- | 59 bytes |
| .get_maintainer.ignore | -rw-r--r-- | 71 bytes |
| .gitattributes | -rw-r--r-- | 62 bytes |
| .gitignore | -rw-r--r-- | 1.9 KB |
| .mailmap | -rw-r--r-- | 23.0 KB |
| COPYING | -rw-r--r-- | 496 bytes |
| CREDITS | -rw-r--r-- | 99.0 KB |
| Kbuild | -rw-r--r-- | 1.3 KB |
| Kconfig | -rw-r--r-- | 555 bytes |
| MAINTAINERS | -rw-r--r-- | 653.4 KB |
| Makefile | -rw-r--r-- | 64.1 KB |
| README | -rw-r--r-- | 727 bytes |
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