Re: Fwd: IGMP and rwlock: Dead ocurred again on TILEPro

On Thu, Feb 17, 2011 at 11:39:22AM +0800, Cypher Wu wrote:

---------- Forwarded message ----------
From: Cypher Wu <redacted>
Date: Wed, Feb 16, 2011 at 5:58 PM
Subject: GMP and rwlock: Dead ocurred again on TILEPro
To: linux-kernel@vger.kernel.org


The rwlock and spinlock of TILEPro platform use TNS instruction to
test the value of lock, but if interrupt is not masked, read_lock()
have another chance to deadlock while read_lock() called in bh of
interrupt.

In this case, you should call read_lock_bh() instead of read_lock().

frame 0: 0xfd3bfbe0 dump_stack+0x0/0x20 (sp 0xe4b5f9d8)
frame 1: 0xfd3c0b50 __raw_read_lock_slow.cold+0x50/0x90 (sp 0xe4b5f9d8)
frame 2: 0xfd184a58 igmpv3_send_cr+0x60/0x440 (sp 0xe4b5f9f0)
frame 3: 0xfd3bd928 igmp_ifc_timer_expire+0x30/0x90 (sp 0xe4b5fa20)
frame 4: 0xfd047698 run_timer_softirq+0x258/0x3c8 (sp 0xe4b5fa30)
frame 5: 0xfd0563f8 __do_softirq+0x138/0x220 (sp 0xe4b5fa70)
frame 6: 0xfd097d48 do_softirq+0x88/0x110 (sp 0xe4b5fa98)
frame 7: 0xfd1871f8 irq_exit+0xf8/0x120 (sp 0xe4b5faa8)
frame 8: 0xfd1afda0 do_timer_interrupt+0xa0/0xf8 (sp 0xe4b5fab0)
frame 9: 0xfd187b98 handle_interrupt+0x2d8/0x2e0 (sp 0xe4b5fac0)
<interrupt 25 while in kernel mode>
frame 10: 0xfd0241c8 _read_lock+0x8/0x40 (sp 0xe4b5fc38)
frame 11: 0xfd1bb008 ip_mc_del_src+0xc8/0x378 (sp 0xe4b5fc40)
frame 12: 0xfd2681e8 ip_mc_leave_group+0xf8/0x1e0 (sp 0xe4b5fc70)
frame 13: 0xfd0a4d70 do_ip_setsockopt+0xe48/0x1560 (sp 0xe4b5fc90)
frame 14: 0xfd2b4168 sys_setsockopt+0x150/0x170 (sp 0xe4b5fe98)
frame 15: 0xfd14e550 handle_syscall+0x2d0/0x320 (sp 0xe4b5fec0)
<syscall while in user mode>
frame 16: 0x3342a0 (sp 0xbfddfb00)
frame 17: 0x16130 (sp 0xbfddfb08)
frame 18: 0x16640 (sp 0xbfddfb38)
frame 19: 0x16ee8 (sp 0xbfddfc58)
frame 20: 0x345a08 (sp 0xbfddfc90)
frame 21: 0x10218 (sp 0xbfddfe48)
Stack dump complete

I don't know the clear definition of rwlock & spinlock in Linux, but
the implementation of other platforms
like x86, PowerPC, ARM don't have that issue. The use of TNS cause a
race condition between system
call and interrupt.

Have you turned CONFIG_LOCKDEP on?

I think Eric already converted that rwlock into RCU lock, thus
this problem should disappear. Could you try a new kernel?

Thanks.