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Mon, 02 Nov 2026 16:52:28 -0800 (PST) Received: from localhost ([211.249.71.105]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3b07c5aa69fsm1428198a91.2.2026.11.02.16.52.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Nov 2026 16:52:25 -0800 (PST) From: Jaewon Jung To: Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH v2] tracing: Keep copying markers when one instance is stopped Date: Tue, 3 Nov 2026 09:44:30 +0900 Message-ID: <20261103005219.3236380-1-jaewon8868@gmail.com> X-Mailer: git-send-email 2.43.0 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When several instances enable copy_trace_marker, stopping one instance can prevent the remaining buffers from receiving markers. Continue copying text and raw markers even if one copy fails. Return the last write's result, keeping -ENODEV when no destinations are selected. Fixes: 7b382efd5e8a ("tracing: Allow the top level trace_marker to write into another instances") Signed-off-by: Jaewon Jung --- All writes are now attempted regardless of errors. The last write's result is returned. Would this approach work? Changes in v2: - Drop the stable Cc. - Do not save earlier copy errors. Return the last write's result. - Rebase onto trace/for-next. Tested on x86_64 QEMU: - Before: Copying stops at the first error, which is returned. Later live buffers receive no markers. - After: All buffers are tried, and the last write's result is returned. - Existing text/raw marker and instance selftests: 6 PASS. kernel/trace/trace.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 08614af8fad1..0b66c55d378b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6330,8 +6330,6 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, guard(rcu)(); list_for_each_entry_rcu(tr, &marker_copies, marker_list) { written = write_marker_to_buffer(tr, buf, cnt, ip); - if (written < 0) - break; } } else { written = write_marker_to_buffer(tr, buf, cnt, ip); @@ -6409,8 +6407,6 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf, guard(rcu)(); list_for_each_entry_rcu(tr, &marker_copies, marker_list) { written = write_raw_marker_to_buffer(tr, buf, cnt); - if (written < 0) - break; } } else { written = write_raw_marker_to_buffer(tr, buf, cnt); base-commit: d7ff48d92a0f28bc0612da47c054efbc28c19562 -- 2.43.0