The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.14.y git checkout FETCH_HEAD git cherry-pick -x 9f116f76fa8c04c81aef33ad870dbf9a158e5b70 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '1679307122237220@kroah.com' --subject-prefix 'PATCH 4.14.y' HEAD^..

Possible dependencies:

9f116f76fa8c ("tracing: Check field value in hist_field_name()") 85013256cf01 ("tracing: Add hist_field_name() accessor")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 9f116f76fa8c04c81aef33ad870dbf9a158e5b70 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" rostedt@goodmis.org Date: Wed, 1 Mar 2023 20:00:53 -0500 Subject: [PATCH] tracing: Check field value in hist_field_name()

The function hist_field_name() cannot handle being passed a NULL field parameter. It should never be NULL, but due to a previous bug, NULL was passed to the function and the kernel crashed due to a NULL dereference. Mark Rutland reported this to me on IRC.

The bug was fixed, but to prevent future bugs from crashing the kernel, check the field and add a WARN_ON() if it is NULL.

Link: https://lkml.kernel.org/r/20230302020810.762384440@goodmis.org

Cc: stable@vger.kernel.org Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Andrew Morton akpm@linux-foundation.org Reported-by: Mark Rutland mark.rutland@arm.com Fixes: c6afad49d127f ("tracing: Add hist trigger 'sym' and 'sym-offset' modifiers") Tested-by: Mark Rutland mark.rutland@arm.com Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 6e8ab726a7b5..486cca3c2b75 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -1331,6 +1331,9 @@ static const char *hist_field_name(struct hist_field *field, { const char *field_name = "";

+ if (WARN_ON_ONCE(!field)) + return field_name; + if (level > 1) return field_name;