linux-kernel - [PATCH 1/2 v3] tracing/core: Add current context on tracing recursion warning

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: <1240178868-18218-2-git-send-email-fweisbec@gmail.com>
Date:	Mon, 20 Apr 2009 00:07:47 +0200
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Ingo Molnar <mingo@...e.hu>, Steven Rostedt <rostedt@...dmis.org>
Cc:	Zhaolei <zhaolei@...fujitsu.com>, Tom Zanussi <tzanussi@...il.com>,
	Li Zefan <lizf@...fujitsu.com>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Frederic Weisbecker <fweisbec@...il.com>
Subject: [PATCH 1/2 v3] tracing/core: Add current context on tracing recursion warning

In case of tracing recursion detection, we only get the stacktrace.
But the current context may be very useful to debug the issue.

This patch adds the softirq/hardirq/nmi context with the warning
using lockdep context display to have a familiar output.

v2: Use printk_once()
v3: drop {hardirq,softirq}_context which depend on lockdep,
    only keep what is part of current->trace_recursion,
    sufficient to debug the warning source.

[ Impact: print context necessary to debug recursion ]

Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
---
 kernel/trace/ring_buffer.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index b421b0e..bffde63 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1495,6 +1495,13 @@ static int trace_recursive_lock(void)
 	if (unlikely(current->trace_recursion & (1 << level))) {
 		/* Disable all tracing before we do anything else */
 		tracing_off_permanent();
+
+		printk_once(KERN_WARNING "Tracing recursion: "
+			    "HC[%lu]:SC[%lu]:NMI[%lu]\n",
+			    hardirq_count() >> HARDIRQ_SHIFT,
+			    softirq_count() >> SOFTIRQ_SHIFT,
+			    in_nmi());
+
 		WARN_ON_ONCE(1);
 		return -1;
 	}
-- 
1.6.2.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/