Wind River Support Network

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.
Data source: kernel.org (416baaa9-dc9f-4396-8d5f-8c081fb06d67)