From: Stephen Hemminger <shemminger@linux-foundation.org>
To: Ben Greear <greearb@candelatech.com>
Cc: NetDev <netdev@vger.kernel.org>
Subject: Re: deadlock in 2.6.18.2 related to bridging?
Date: Wed, 14 Feb 2007 13:12:05 -0800 [thread overview]
Message-ID: <20070214131205.1ace04ba@freekitty> (raw)
In-Reply-To: <45D26479.7030103@candelatech.com>
On Tue, 13 Feb 2007 17:23:05 -0800
Ben Greear <greearb@candelatech.com> wrote:
> I think I may have found a deadlock bug in 2.6.18.2. This is
> with my hacked kernel, but my binary module has not been loaded.
>
> I have several bridges configured, including some containing
> my redirect-device virtual devices and ethernet devices.
>
> I believe the deadlock is this:
>
> The work-queue process is calling this, and is blocked on
> rtnl:
>
> [<c0337ede>] __mutex_lock_slowpath+0xbe/0x2a0
> [<c03380dc>] mutex_lock+0x1c/0x20
> [<c02dd1db>] __rtnl_lock+0x1b/0x40
> [<df909dc2>] port_carrier_check+0x22/0xa0 [bridge]
> [<c012d21b>] run_workqueue+0x7b/0x100
> [<c012d9cf>] worker_thread+0x10f/0x130
> [<c01304b5>] kthread+0xd5/0xe0
> [<c0101005>] kernel_thread_helper+0x5/0x10
It is waiting for the other function to finish (in this case the ioctl).
>
> But, the 'ip' program already has rtnl (acquired in devinet_ioctl),
> and is trying to flush the work-queue:
>
> ip D D9C34000 6600 2780 2775 (NOTLB)
> d9c35e1c 00000046 deeebae8 d9c34000 c010327f 00000001 d9c34000 00000260
> deeeba80 00000001 d9c542b0 e548f009 0000001a 00020224 d9c543c0 0000007b
> 0000007b 00335517 00000000 deeeba80 deeebae8 00000053 d9c35e44 c012d30b
> Call Trace:
> [<c012d30b>] flush_cpu_workqueue+0x6b/0xb0
> [<c012d388>] flush_workqueue+0x38/0x50
> [<c012d3fd>] flush_scheduled_work+0xd/0x10
> [<df819665>] rtl8139_close+0x165/0x1a0 [8139too]
> [<c02d4bd4>] dev_close+0x54/0x70
> [<c02d3e31>] dev_change_flags+0x51/0x110
> [<c0314e90>] devinet_ioctl+0x4b0/0x6a0
> [<c031579b>] inet_ioctl+0x6b/0x80
> [<c02c9627>] sock_ioctl+0x77/0x250
> [<c017e1f8>] do_ioctl+0x28/0x80
> [<c017e2a7>] vfs_ioctl+0x57/0x2b0
> [<c017e539>] sys_ioctl+0x39/0x60
> [<c01031ad>] sysenter_past_esp+0x56/0x99
> [<b7fd5410>] 0xb7fd5410
The bug is in r8139too.c driver. It calls flush_scheduled_work
with RTNL mutex held, so any other work using it will get stuck.
>
> Has this been fixed in later releases?
No but a different race (with device removal) has been fixed.
--
Stephen Hemminger <shemminger@linux-foundation.org>
next prev parent reply other threads:[~2007-02-14 21:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-14 1:23 deadlock in 2.6.18.2 related to bridging? Ben Greear
2007-02-14 21:12 ` Stephen Hemminger [this message]
2007-02-14 21:26 ` Ben Greear
2007-02-14 23:37 ` Francois Romieu
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