This is a note to let you know that I've just added the patch titled tracing: Fix the checking of stackidx in __ftrace_trace_stack to the 5.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tracing-fix-the-checking-of-stackidx-in-__ftrace_tra.patch and it can be found in the queue-5.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 3d3697189d496aacb9f0f45729f3d13806360577 Author: Qiujun Huang <hqjagain@xxxxxxxxx> Date: Sat Oct 31 16:57:14 2020 +0800 tracing: Fix the checking of stackidx in __ftrace_trace_stack [ Upstream commit 906695e59324635c62b5ae59df111151a546ca66 ] The array size is FTRACE_KSTACK_NESTING, so the index FTRACE_KSTACK_NESTING is illegal too. And fix two typos by the way. Link: https://lkml.kernel.org/r/20201031085714.2147-1-hqjagain@xxxxxxxxx Signed-off-by: Qiujun Huang <hqjagain@xxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6e2fb7dc41bf3..1c76a0faf3cd1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2611,7 +2611,7 @@ trace_event_buffer_lock_reserve(struct trace_buffer **current_rb, /* * If tracing is off, but we have triggers enabled * we still need to look at the event data. Use the temp_buffer - * to store the trace event for the tigger to use. It's recusive + * to store the trace event for the trigger to use. It's recursive * safe and will not be recorded anywhere. */ if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) { @@ -2934,7 +2934,7 @@ static void __ftrace_trace_stack(struct trace_buffer *buffer, stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1; /* This should never happen. If it does, yell once and skip */ - if (WARN_ON_ONCE(stackidx > FTRACE_KSTACK_NESTING)) + if (WARN_ON_ONCE(stackidx >= FTRACE_KSTACK_NESTING)) goto out; /*