CVE-2022-49977: 
Linux Kernel vulnerability analysis and mitigation

A vulnerability (CVE-2022-49977) was identified in the Linux kernel's ftrace functionality where a NULL pointer dereference could occur in the is_ftrace_trampoline function when ftrace is disabled. The issue was discovered and reported through the Syzkaller kernel testing tool (NVD).

The vulnerability occurs when ftrace_startup_enable fails but does not properly clean up the operations from the ftrace_ops_list. When ftrace_disabled is set to 1, unregister_ftrace_function returns without executing __unregister_ftrace_function, leaving the ops in the list. If the ops is dynamically allocated and later freed, is_ftrace_trampoline will attempt to access a NULL pointer, resulting in a kernel crash (NVD, Wiz).

When exploited, this vulnerability can cause a kernel crash through NULL pointer dereference, potentially leading to denial of service conditions on affected systems (Wiz).

The fix involves properly rolling back the registration process and removing ops from ftrace_ops_list when ftrace_startup_enable fails. This ensures that no dangling pointers remain in the list that could lead to NULL pointer dereference (Wiz).