The patch below does not apply to the 5.4-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-5.4.y git checkout FETCH_HEAD git cherry-pick -x 9d52727f8043cfda241ae96896628d92fa9c50bb # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023041138-snaking-richness-7cd0@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:

9d52727f8043 ("tracing: Have tracing_snapshot_instance_cond() write errors to the appropriate instance")

thanks,

greg k-h

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

From 9d52727f8043cfda241ae96896628d92fa9c50bb Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" rostedt@goodmis.org Date: Tue, 4 Apr 2023 22:21:14 -0400 Subject: [PATCH] tracing: Have tracing_snapshot_instance_cond() write errors to the appropriate instance

If a trace instance has a failure with its snapshot code, the error message is to be written to that instance's buffer. But currently, the message is written to the top level buffer. Worse yet, it may also disable the top level buffer and not the instance that had the issue.

Link: https://lkml.kernel.org/r/20230405022341.688730321@goodmis.org

Cc: stable@vger.kernel.org Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mark Rutland mark.rutland@arm.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Ross Zwisler zwisler@google.com Fixes: 2824f50332486 ("tracing: Make the snapshot trigger work with instances") Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 937e9676dfd4..ed1d1093f5e9 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1149,22 +1149,22 @@ static void tracing_snapshot_instance_cond(struct trace_array *tr, unsigned long flags;

if (in_nmi()) { - internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n"); - internal_trace_puts("*** snapshot is being ignored ***\n"); + trace_array_puts(tr, "*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n"); + trace_array_puts(tr, "*** snapshot is being ignored ***\n"); return; }

if (!tr->allocated_snapshot) { - internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n"); - internal_trace_puts("*** stopping trace here! ***\n"); - tracing_off(); + trace_array_puts(tr, "*** SNAPSHOT NOT ALLOCATED ***\n"); + trace_array_puts(tr, "*** stopping trace here! ***\n"); + tracer_tracing_off(tr); return; }

/* Note, snapshot can not be used when the tracer uses it */ if (tracer->use_max_tr) { - internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n"); - internal_trace_puts("*** Can not use snapshot (sorry) ***\n"); + trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n"); + trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n"); return; }