From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB7572C235E; Mon, 6 Oct 2025 17:58:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759773537; cv=none; b=kL6mjzjBS8Boe1aYCR/HnKNK2LXO/S3DSY6RFWdyiBYTXgPPnmjArycQE0hWDgwXx7pBCShYrXJwwRHuf8kg2Lz3vCtes7SCM2N0YSLhD4HwWVjSCYByKqvkqF4LymxSxfkx4sUNjEYdWtSBLw5AEfknK7yg7MQKcv/mpwWyEdY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759773537; c=relaxed/simple; bh=rwl1eMVoOI34wgRRQ/sE+tlqYZUKrsAzxbwQaW/U1GU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=DxsFYSGXALFuTBSaxxsIw0BmkzDtWoQ92YnhjIVfVmESJoq7XtZw0p5iSzXZGiyDPSboDISa62yZBhBbpiHHyLezp3J8vkt3xYByr8BuYck+0YPlW/pb0tR7MpKlreiYJCJOvNeiNLvxpKmG6VhDurXV4JkXox0oXT6w5cLbCro= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fo6WZMdQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fo6WZMdQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5823C4CEF7; Mon, 6 Oct 2025 17:58:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1759773536; bh=rwl1eMVoOI34wgRRQ/sE+tlqYZUKrsAzxbwQaW/U1GU=; h=From:To:Cc:Subject:Date:From; b=fo6WZMdQk5bcnLBV024NYrXXSNzF/6lMcqyIyRVa53zB3g+bXuzJAq44V5E/iEEWN g0ea0BUG0McLqKKTRooGkFdroMc8Cy+m6bYz22SPtGv5Ncya/d7I+VSt+qDBjjhtJE IzT/8Y4K2MwVx0Rch6kWB35f/PLxChfSbO6B7gwGdbnQrJ/GE2nM0hOkxU4zThEmvJ fFNA6DmRN9+saB3//hTqY5oYZ8dGI8x1xDAzJS78KJaVLukVHDzG3Fn7TimB+BibMn gxQOlsjin0UJQ6V5a+2VjCk962SAYKbvCUrhOL59zM0OJQGfmSDYsmOGs6QmAJjjK5 oe7YyctzKrC4A== From: Sasha Levin To: rostedt@goodmis.org, mhiramat@kernel.org Cc: mathieu.desnoyers@efficios.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Sasha Levin Subject: [PATCH 1/2] tracing/wakeup: Balance prolog on fgraph failure Date: Mon, 6 Oct 2025 13:58:47 -0400 Message-ID: <20251006175848.1906912-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Commit a485ea9e3ef3 ("tracing: Fix irqsoff and wakeup latency tracers when using function graph") added fgraph_reserve_data()/fgraph_retrieve_data() to the wakeup tracer's function-graph hooks. When func_prolog_preempt_disable() succeeded but those calls failed, the code returned without undoing the prolog (no local_dec(&data->disabled), no preempt_enable_notrace()). That leaked a preempt disable into later code and could trigger "BUG: scheduling while atomic". Balance the prolog on these failure paths in both entry and return hooks. Fixes: a485ea9e3ef3 ("tracing: Fix irqsoff and wakeup latency tracers when using function graph") Assisted-by: gpt-5-codex Signed-off-by: Sasha Levin --- kernel/trace/trace_sched_wakeup.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index bf1cb80742aed..fa48bbdf0851c 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -138,8 +138,11 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace, return 0; calltime = fgraph_reserve_data(gops->idx, sizeof(*calltime)); - if (!calltime) + if (!calltime) { + local_dec(&data->disabled); + preempt_enable_notrace(); return 0; + } *calltime = trace_clock_local(); @@ -169,8 +172,11 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace, rettime = trace_clock_local(); calltime = fgraph_retrieve_data(gops->idx, &size); - if (!calltime) + if (!calltime) { + local_dec(&data->disabled); + preempt_enable_notrace(); return; + } __trace_graph_return(tr, trace, trace_ctx, *calltime, rettime); local_dec(&data->disabled); -- 2.51.0