From: Vladimir Oltean <vladimir.oltean@nxp.com> stable inclusion from stable-v6.6.88 commit bbb80f004f7a90c3dcaacc982c59967457254a05 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IC5BMR CVE: CVE-2025-37787 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit c84f6ce918a9e6f4996597cbc62536bbf2247c96 ] Russell King reports that a system with mv88e6xxx dereferences a NULL pointer when unbinding this driver: https://lore.kernel.org/netdev/Z_lRkMlTJ1KQ0kVX@shell.armlinux.org.uk/ The crash seems to be in devlink_region_destroy(), which is not NULL tolerant but is given a NULL devlink global region pointer. At least on some chips, some devlink regions are conditionally registered since the blamed commit, see mv88e6xxx_setup_devlink_regions_global(): if (cond && !cond(chip)) continue; These are MV88E6XXX_REGION_STU and MV88E6XXX_REGION_PVT. If the chip does not have an STU or PVT, it should crash like this. To fix the issue, avoid unregistering those regions which are NULL, i.e. were skipped at mv88e6xxx_setup_devlink_regions_global() time. Fixes: 836021a2d0e0 ("net: dsa: mv88e6xxx: Export cross-chip PVT as devlink region") Tested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Link: https://patch.msgid.link/20250414212850.2953957-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Wang Liang <wangliang74@huawei.com> --- drivers/net/dsa/mv88e6xxx/devlink.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/dsa/mv88e6xxx/devlink.c b/drivers/net/dsa/mv88e6xxx/devlink.c index a08dab75e0c0..f57fde02077d 100644 --- a/drivers/net/dsa/mv88e6xxx/devlink.c +++ b/drivers/net/dsa/mv88e6xxx/devlink.c @@ -743,7 +743,8 @@ void mv88e6xxx_teardown_devlink_regions_global(struct dsa_switch *ds) int i; for (i = 0; i < ARRAY_SIZE(mv88e6xxx_regions); i++) - dsa_devlink_region_destroy(chip->regions[i]); + if (chip->regions[i]) + dsa_devlink_region_destroy(chip->regions[i]); } void mv88e6xxx_teardown_devlink_regions_port(struct dsa_switch *ds, int port) -- 2.34.1