Re: [PATCH resend 6/8] tracing/ftrace: Add might_fault check to syscall probes
From: Thomas Gleixner <hidden>
Date: 2024-10-28 17:42:09
Also in:
bpf, lkml
On Mon, Sep 30 2024 at 15:23, Mathieu Desnoyers wrote:
quoted hunk ↗ jump to hunk
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index a3d8ac00793e..0430890cbb42 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c@@ -303,6 +303,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) * Syscall probe called with preemption enabled, but the ring * buffer and per-cpu data require preemption to be disabled. */ + might_fault(); guard(preempt_notrace)();
I find it odd that the might_fault() check is in all the implementations
and not in the tracepoint itself:
if (syscall) {
might_fault();
rcu_read_unlock_trace();
} else ...
That's where I would have expected it to be.
Thanks,
tglx