tracing: Fix syscall tracepoint use-after-free
The grace period used internally within tracepoint.c:release_probes() uses call_rcu() to batch waiting for quiescence of old probe arrays, rather than using the tracepoint_synchronize_unregister() which blocks while waiting for quiescence. With the introduction of faultable syscall tracepoints, this causes use-after-free issues reproduced with syzkaller. Fix this by using the appropriate call_rcu() or call_rcu_tasks_trace() before invoking the rcu_free_old_probes callback. This can be chosen using the tracepoint_is_faultable() API. A similar issue exists in bpf use of call_rcu(). Fixing this is left to a separate change. Reported-by:<syzbot+b390c8062d8387b6272a@syzkaller.appspotmail.com> Fixes: a363d27c ("tracing: Allow system call tracepoints to handle page faults") Tested-by:
Jordan Rife <jrife@google.com> Cc: Michael Jeanson <mjeanson@efficios.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Yonghong Song <yhs@fb.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: bpf@vger.kernel.org Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Jordan Rife <jrife@google.com> Cc: linux-trace-kernel@vger.kernel.org Link: https://lore.kernel.org/20241031152056.744137-4-mathieu.desnoyers@efficios.com Signed-off-by:
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by:
Steven Rostedt (Google) <rostedt@goodmis.org>
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