linux-kernel - [PATCH v2 10/15] tracing: Stop the tracing while changing the ring buffer subbuf size

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20231213022010.851142884@goodmis.org>
Date:   Tue, 12 Dec 2023 21:19:24 -0500
From:   Steven Rostedt <rostedt@...dmis.org>
To:     linux-kernel@...r.kernel.org
Cc:     Masami Hiramatsu <mhiramat@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Tzvetomir Stoyanov <tz.stoyanov@...il.com>,
        Vincent Donnefort <vdonnefort@...gle.com>,
        Kent Overstreet <kent.overstreet@...il.com>
Subject: [PATCH v2 10/15] tracing: Stop the tracing while changing the ring buffer subbuf size

From: "Steven Rostedt (Google)" <rostedt@...dmis.org>

Because the main buffer and the snapshot buffer need to be the same for
some tracers, otherwise it will fail and disable all tracing, the tracers
need to be stopped while updating the sub buffer sizes so that the tracers
see the main and snapshot buffers with the same sub buffer size.

Fixes: TBD ("ring-buffer: Add interface for configuring trace sub buffer size")
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
---
 kernel/trace/trace.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7c5ef3f33d81..0cb5e1a50e65 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -9405,13 +9405,16 @@ buffer_order_write(struct file *filp, const char __user *ubuf,
 	if (val < 0 || val > 7)
 		return -EINVAL;
 
+	/* Do not allow tracing while changing the order of the ring buffer */
+	tracing_stop_tr(tr);
+
 	old_order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
 	if (old_order == val)
-		return 0;
+		goto out;
 
 	ret = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, val);
 	if (ret)
-		return 0;
+		goto out;
 
 #ifdef CONFIG_TRACER_MAX_TRACE
 
@@ -9438,11 +9441,15 @@ buffer_order_write(struct file *filp, const char __user *ubuf,
 			 */
 			tracing_disabled = 1;
 		}
-		return ret;
+		goto out;
 	}
  out_max:
 #endif
 	(*ppos)++;
+ out:
+	if (ret)
+		cnt = ret;
+	tracing_start_tr(tr);
 	return cnt;
 }
 
-- 
2.42.0