| ID |
CVE-2026-53064
|
| Sažetak |
In the Linux kernel, the following vulnerability has been resolved:
dm cache: fix null-deref with concurrent writes in passthrough mode
In passthrough mode, when dm-cache starts to invalidate a cache
entry and bio prison cell lock fails due to concurrent write to
the same cached block, mg->cell remains NULL. The error path in
invalidate_complete() attempts to unlock and free the cell
unconditionally, causing a NULL pointer dereference:
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 134 Comm: fio Not tainted 6.19.0-rc7 #3 PREEMPT
RIP: 0010:dm_cell_unlock_v2+0x3f/0x210
<snip>
Call Trace:
invalidate_complete+0xef/0x430
map_bio+0x130f/0x1a10
cache_map+0x320/0x6b0
__map_bio+0x458/0x510
dm_submit_bio+0x40e/0x16d0
__submit_bio+0x419/0x870
<snip>
Reproduce steps:
1. Create a cache device
dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
dmsetup create cdata --table "0 131072 linear /dev/sdc 8192"
dmsetup create corig --table "0 262144 linear /dev/sdc 262144"
dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct
dmsetup create cache --table "0 262144 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"
2. Promote the first data block into cache
fio --filename=/dev/mapper/cache --name=populate --rw=write --bs=4k \
--direct=1 --size=64k
3. Reload the cache into passthrough mode
dmsetup suspend cache
dmsetup reload cache --table "0 262144 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 passthrough smq 0"
dmsetup resume cache
4. Write to the first cached block concurrently
fio --filename=/dev/mapper/cache --name test --rw=randwrite --bs=4k \
--randrepeat=0 --direct=1 --numjobs=2 --size 64k
Fix by checking if mg->cell is valid before attempting to unlock it. |
| Reference |
|
| CVSS |
| Base: | 0.0 |
| Impact: | None |
| Exploitability: | None |
|
| Pristup |
| Vektor | Složenost | Autentikacija |
| None |
None |
None |
|
| Impact |
| Povjerljivost | Cjelovitost | Dostupnost |
| None |
None |
None |
|
| CVSS vektor |
None |
| Zadnje važnije ažuriranje |
24-06-2026 - 17:17 |
| Objavljeno |
24-06-2026 - 17:17 |
