CVE-2025-71102

Summary

In the Linux kernel, the following vulnerability has been resolved:

scs: fix a wrong parameter in __scs_magic

__scs_magic() needs a 'void *' variable, but a 'struct task_struct *' is given. 'task_scs(tsk)' is the starting address of the task's shadow call stack, and '__scs_magic(task_scs(tsk))' is the end address of the task's shadow call stack. Here should be '__scs_magic(task_scs(tsk))'.

The user-visible effect of this bug is that when CONFIG_DEBUG_STACK_USAGE is enabled, the shadow call stack usage checking function (scs_check_usage) would scan an incorrect memory range. This could lead

  1. Inaccurate stack usage reporting: The function would calculate wrong usage statistics for the shadow call stack, potentially showing incorrect value in kmsg.

  2. Potential kernel crash: If the value of __scs_magic(tsk)is greater than that of __scs_magic(task_scs(tsk)), the for loop may access unmapped memory, potentially causing a kernel panic. However, this scenario is unlikely because task_struct is allocated via the slab allocator (which typically returns lower addresses), while the shadow call stack returned by task_scs(tsk) is allocated via vmalloc(which typically returns higher addresses).

However, since this is purely a debugging feature (CONFIG_DEBUG_STACK_USAGE), normal production systems should be not unaffected. The bug only impacts developers and testers who are actively debugging stack usage with this configuration enabled.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux5bbaf9d1fcb9be696ee9a61636ab6803556c70f2 < 1727e8bd69103a68963a5613a0ddb6d8d37df5d3affected
LinuxLinux5bbaf9d1fcb9be696ee9a61636ab6803556c70f2 < cfdf6250b63b953b1d8e60814c8ca96c6f9d1c8caffected
LinuxLinux5bbaf9d1fcb9be696ee9a61636ab6803556c70f2 < 57ba40b001be27786d0570dd292289df748b306baffected
LinuxLinux5bbaf9d1fcb9be696ee9a61636ab6803556c70f2 < 062774439d442882b44f5eab8c256ad3423ef284affected
LinuxLinux5bbaf9d1fcb9be696ee9a61636ab6803556c70f2 < 9ef28943471a16e4f9646bc3e8e2de148e7d8d7baffected
LinuxLinux5bbaf9d1fcb9be696ee9a61636ab6803556c70f2 < a19fb3611e4c06624fc0f83ef19f4fb8d57d4751affected
LinuxLinux5bbaf9d1fcb9be696ee9a61636ab6803556c70f2 < 08bd4c46d5e63b78e77f2605283874bbe868ab19affected
LinuxLinux5.8affected
LinuxLinux0 < 5.8unaffected
LinuxLinux5.10.248 <= 5.10.*unaffected
LinuxLinux5.15.198 <= 5.15.*unaffected
LinuxLinux6.1.160 <= 6.1.*unaffected
LinuxLinux6.6.120 <= 6.6.*unaffected
LinuxLinux6.12.64 <= 6.12.*unaffected
LinuxLinux6.18.3 <= 6.18.*unaffected
LinuxLinux6.19 <= *unaffected

Weaknesses

References