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From: Florian Westphal <fw@strlen•de>
To: <netdev@vger•kernel.org>
Cc: Florian Westphal <fw@strlen•de>,
	syzbot+51471b4aae195285a4a3@syzkaller•appspotmail.com
Subject: [PATCH net-next] net: use correct this_cpu primitive in dev_recursion_level
Date: Wed,  3 Apr 2019 08:28:35 +0200	[thread overview]
Message-ID: <20190403062835.23920-1-fw@strlen.de> (raw)
In-Reply-To: <000000000000db3c59058595f0ac@google.com>

syzbot reports:
BUG: using __this_cpu_read() in preemptible code:
caller is dev_recursion_level include/linux/netdevice.h:3052 [inline]
 __this_cpu_preempt_check+0x246/0x270 lib/smp_processor_id.c:47
 dev_recursion_level include/linux/netdevice.h:3052 [inline]
 ip6_skb_dst_mtu include/net/ip6_route.h:245 [inline]

I erronously downgraded a this_cpu_read to __this_cpu_read when
moving dev_recursion_level() around.

Reported-by: syzbot+51471b4aae195285a4a3@syzkaller•appspotmail.com
Fixes: 97cdcf37b57e ("net: place xmit recursion in softnet data")
Signed-off-by: Florian Westphal <fw@strlen•de>
---
 include/linux/netdevice.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index eb9f05e0863d..521eb869555e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3049,7 +3049,7 @@ DECLARE_PER_CPU_ALIGNED(struct softnet_data, softnet_data);
 
 static inline int dev_recursion_level(void)
 {
-	return __this_cpu_read(softnet_data.xmit.recursion);
+	return this_cpu_read(softnet_data.xmit.recursion);
 }
 
 #define XMIT_RECURSION_LIMIT	10
-- 
2.21.0


  reply	other threads:[~2019-04-03  6:31 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-02 22:44 BUG: using __this_cpu_read() in preemptible code in ip6_finish_output syzbot
2019-04-03  1:12 ` syzbot
2019-04-03  6:28   ` Florian Westphal [this message]
2019-04-03 12:18     ` [PATCH net-next] net: use correct this_cpu primitive in dev_recursion_level Eric Dumazet
2019-04-05  0:35     ` David Miller
2019-04-05  7:00   ` BUG: using __this_cpu_read() in preemptible code in ip6_finish_output Krzysztof Kozlowski
2019-04-05 10:08     ` Florian Westphal
2019-04-05 12:36       ` Dmitry Vyukov

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