From: David Miller <davem@davemloft.net>
To: xiyou.wangcong@gmail.com
Cc: netdev@vger.kernel.org, andreyknvl@google.com
Subject: Re: [Patch net] igmp: add a missing spin_lock_init()
Date: Tue, 20 Jun 2017 15:52:29 -0400 (EDT) [thread overview]
Message-ID: <20170620.155229.1782557175397900375.davem@davemloft.net> (raw)
In-Reply-To: <1497980787-4040-1-git-send-email-xiyou.wangcong@gmail.com>
From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Tue, 20 Jun 2017 10:46:27 -0700
> Andrey reported a lockdep warning on non-initialized
> spinlock:
>
> INFO: trying to register non-static key.
> the code is fine but needs lockdep annotation.
> turning off the locking correctness validator.
> CPU: 1 PID: 4099 Comm: a.out Not tainted 4.12.0-rc6+ #9
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:16
> dump_stack+0x292/0x395 lib/dump_stack.c:52
> register_lock_class+0x717/0x1aa0 kernel/locking/lockdep.c:755
> ? 0xffffffffa0000000
> __lock_acquire+0x269/0x3690 kernel/locking/lockdep.c:3255
> lock_acquire+0x22d/0x560 kernel/locking/lockdep.c:3855
> __raw_spin_lock_bh ./include/linux/spinlock_api_smp.h:135
> _raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:175
> spin_lock_bh ./include/linux/spinlock.h:304
> ip_mc_clear_src+0x27/0x1e0 net/ipv4/igmp.c:2076
> igmpv3_clear_delrec+0xee/0x4f0 net/ipv4/igmp.c:1194
> ip_mc_destroy_dev+0x4e/0x190 net/ipv4/igmp.c:1736
>
> We miss a spin_lock_init() in igmpv3_add_delrec(), probably
> because previously we never use it on this code path. Since
> we already unlink it from the global mc_tomb list, it is
> probably safe not to acquire this spinlock here. It does not
> harm to have it although, to avoid conditional locking.
>
> Fixes: c38b7d327aaf ("igmp: acquire pmc lock for ip_mc_clear_src()")
> Reported-by: Andrey Konovalov <andreyknvl@google.com>
> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Applied and queued up for -stable, thank you.
prev parent reply other threads:[~2017-06-20 19:52 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-20 17:46 [Patch net] igmp: add a missing spin_lock_init() Cong Wang
2017-06-20 19:52 ` David Miller [this message]
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