CVE-2026-99247tracing: Do not initialize tracefs work if tracing is disabled

Official description

In the Linux kernel, the following vulnerability has been resolved: tracing: Do not initialize tracefs work if tracing is disabled If trace buffer allocation fails during early boot (e.g. in early_trace_init() -> allocate_trace_buffers()), tracing_disabled is left set to 1 and the global trace array events list remains uninitialized. Later during boot, tracer_init_tracefs() (invoked via fs_initcall) queues tracerfs_init_work asynchronously without checking if tracing was disabled. When tracer_init_tracefs_work_func() runs, it calls event_trace_init() and init_tracer_tracefs(&global_trace, NULL) unconditionally. This leads to __find_event_file() dereferencing an uninitialized tr->events list, causing an early boot NULL pointer dereference Oops: BUG: Kernel NULL pointer dereference on read at 0x00000010 Faulting instruction address: 0xc000000000485be0 Oops: Kernel access of bad area, sig: 7 [#1] ... NIP [c000000000485be0] __find_event_file+0x70/0x3c0 LR [c000000000448874] init_tracer_tracefs+0x274/0xc80 Call Trace: init_tracer_tracefs+0x274/0xc80 tracer_init_tracefs_work_func+0x50/0x320 process_one_work+0x1e8/0x5c0 worker_thread+0x1dc/0x3d0 kthread+0x194/0x1b0 start_kernel_thread+0x14/0x18 Check tracing_disabled at the beginning of tracer_init_tracefs_work_func() and return immediately if tracing is disabled or failed to initialize, preventing the crash.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/e8665e884e076d894f3eed8b9ea28e37a6448604
• https://git.kernel.org/stable/c/e8cfcd7e60eaa3b0dea4d71c64499604e7081736
• https://git.kernel.org/stable/c/afd38b10b1c6a5c5d6952b15b990596dab9684e6
• https://git.kernel.org/stable/c/813e18881c6472eb229a63180ff42c808e3e949b
• https://git.kernel.org/stable/c/7539c61f522ff693d9565a0411386c2236e776cd
• https://git.kernel.org/stable/c/b3b974008388ab59e44d764ba7a63c988fec2524