Re: [BUG 3.3-rc2] spinlock trylock failure on UP on CPU#0
From: Knut Petersen
Date: Mon Feb 06 2012 - 02:15:20 EST
Am 06.02.2012 02:25, schrieb Shaohua Li:
2012/2/6 Linus Torvalds<torvalds@xxxxxxxxxxxxxxxxxxxx>:
Jens, Tejun - the crazy-ass games that this code is playing is clearly
messing not just with lockdep, it's messing with some very reasonable
spinlock sanity checks on UP (which just boil down to "a spinlock
should never have contention on UP")
Any chance of sanitizing this all?
I just sent out a debug patch, please try:
http://marc.info/?l=linux-kernel&m=132849146702770&w=2
Your debug patch helps - but with you patch applied another problem is back again:
3.2.1 ... 3.2.4
===========
dvb-s reception with kaffeine works well, but starting kaffeine
triggers a circular locking dependency warning, see:
http://www.gossamer-threads.com/lists/linux/kernel/1487577
3.3-rc2+ (23783f817bceedd6d4e549385e3f400ea64059e5)
===============================================
spinlock trylock failure on UP on CPU#0 warning is triggered during system startup,
dvb-s with kaffeine is broken (only about 1-2 fps, video frames and audio distorted),
the circular locking dependency warning mentioned above is gone.
3.3-rc2+ (23783f817bceedd6d4e549385e3f400ea64059e5) + blk-icq-lock-fix.patch
=================================================================
spinlock trylock failure warning during system startup is gone,
dvb-s reception with kaffeine is still broken,
the circular locking dependency warning is triggered again by kaffeine:
[ 124.314255]
[ 124.314262] ======================================================
[ 124.314270] [ INFO: possible circular locking dependency detected ]
[ 124.314279] 3.3.0-rc2-main+ #22 Not tainted
[ 124.314285] -------------------------------------------------------
[ 124.314293] kaffeine/3743 is trying to acquire lock:
[ 124.314300] (&fe->lock){+.+.+.}, at: [<f85e70cf>] videobuf_dvb_find_frontend+0x16/0x3e [videobuf_dvb]
[ 124.314320]
[ 124.314321] but task is already holding lock:
[ 124.314327] (minor_rwsem#2){++++..}, at: [<f8e430c8>] dvb_device_open+0x24/0x185 [dvb_core]
[ 124.314348]
[ 124.314349] which lock already depends on the new lock.
[ 124.314351]
[ 124.314359]
[ 124.314360] the existing dependency chain (in reverse order) is:
[ 124.314369]
[ 124.314370] -> #2 (minor_rwsem#2){++++..}:
[ 124.314382] [<c0149609>] lock_acquire+0x45/0x5c
[ 124.314394] [<c0441070>] down_write+0x1b/0x36
[ 124.314405] [<f8e43521>] dvb_register_device+0x113/0x1ed [dvb_core]
[ 124.314420] [<f8e4b320>] dvb_register_frontend+0x172/0x19e [dvb_core]
[ 124.314437] [<f85e7266>] videobuf_dvb_register_bus+0xbe/0x2cb [videobuf_dvb]
[ 124.314450] [<f86d0c9e>] cx8802_dvb_probe+0x1eac/0x1f22 [cx88_dvb]
[ 124.314464] [<f857a420>] cx8802_register_driver+0x116/0x1cc [cx8802]
[ 124.314479] [<f8ce701c>] 0xf8ce701c
[ 124.314490] [<c0101070>] do_one_initcall+0x70/0x118
[ 124.314500] [<c01504d1>] sys_init_module+0x12a3/0x1543
[ 124.314510] [<c0442bf5>] syscall_call+0x7/0xb
[ 124.314520]
[ 124.314521] -> #1 (dvbdev_register_lock){+.+.+.}:
[ 124.314532] [<c0149609>] lock_acquire+0x45/0x5c
[ 124.314541] [<c0440b37>] mutex_lock_nested+0x35/0x275
[ 124.314550] [<f8e4342d>] dvb_register_device+0x1f/0x1ed [dvb_core]
[ 124.314564] [<f8e439a5>] dvb_dmxdev_init+0xc0/0xf0 [dvb_core]
[ 124.314577] [<f85e7311>] videobuf_dvb_register_bus+0x169/0x2cb [videobuf_dvb]
[ 124.314589] [<f86d0c9e>] cx8802_dvb_probe+0x1eac/0x1f22 [cx88_dvb]
[ 124.314601] [<f857a420>] cx8802_register_driver+0x116/0x1cc [cx8802]
[ 124.314612] [<f8ce701c>] 0xf8ce701c
[ 124.314620] [<c0101070>] do_one_initcall+0x70/0x118
[ 124.314629] [<c01504d1>] sys_init_module+0x12a3/0x1543
[ 124.314638] [<c0442bf5>] syscall_call+0x7/0xb
[ 124.314647]
[ 124.314648] -> #0 (&fe->lock){+.+.+.}:
[ 124.314658] [<c0148d54>] __lock_acquire+0xd88/0x12b8
[ 124.314667] [<c0149609>] lock_acquire+0x45/0x5c
[ 124.314675] [<c0440b37>] mutex_lock_nested+0x35/0x275
[ 124.314684] [<f85e70cf>] videobuf_dvb_find_frontend+0x16/0x3e [videobuf_dvb]
[ 124.314695] [<f86ced7a>] cx88_dvb_bus_ctrl+0x22/0x9a [cx88_dvb]
[ 124.314707] [<f8e4982f>] dvb_frontend_open+0x14b/0x2ee [dvb_core]
[ 124.314722] [<f8e43173>] dvb_device_open+0xcf/0x185 [dvb_core]
[ 124.314735] [<c0194f15>] chrdev_open+0x14e/0x16c
[ 124.314754] [<c019056b>] __dentry_open+0x193/0x288
[ 124.314768] [<c01913a9>] nameidata_to_filp+0x42/0x50
[ 124.314780] [<c019c89b>] do_last+0x6db/0x6ed
[ 124.314793] [<c019c973>] path_openat+0xa1/0x2c2
[ 124.314805] [<c019cc40>] do_filp_open+0x21/0x5d
[ 124.314818] [<c01914a5>] do_sys_open+0xee/0x167
[ 124.314830] [<c019153d>] sys_open+0x1f/0x27
[ 124.314842] [<c0442bf5>] syscall_call+0x7/0xb
[ 124.314855]
[ 124.314856] other info that might help us debug this:
[ 124.314857]
[ 124.314876] Chain exists of:
[ 124.314877] &fe->lock --> dvbdev_register_lock --> minor_rwsem#2
[ 124.314896]
[ 124.314906] Possible unsafe locking scenario:
[ 124.314908]
[ 124.314921] CPU0 CPU1
[ 124.314931] ---- ----
[ 124.314940] lock(minor_rwsem#2);
[ 124.314951] lock(dvbdev_register_lock);
[ 124.314964] lock(minor_rwsem#2);
[ 124.314977] lock(&fe->lock);
[ 124.314987]
[ 124.314987] *** DEADLOCK ***
[ 124.314989]
[ 124.315007] 2 locks held by kaffeine/3743:
[ 124.315016] #0: (dvbdev_mutex){+.+...}, at: [<f8e430be>] dvb_device_open+0x1a/0x185 [dvb_core]
[ 124.315040] #1: (minor_rwsem#2){++++..}, at: [<f8e430c8>] dvb_device_open+0x24/0x185 [dvb_core]
[ 124.315065]
[ 124.315066] stack backtrace:
[ 124.315080] Pid: 3743, comm: kaffeine Not tainted 3.3.0-rc2-main+ #22
[ 124.315091] Call Trace:
[ 124.315103] [<c011dd19>] ? console_unlock+0x1ad/0x1d3
[ 124.315116] [<c043cfa8>] print_circular_bug+0x215/0x222
[ 124.315129] [<c0148d54>] __lock_acquire+0xd88/0x12b8
[ 124.315141] [<c0103d67>] ? print_context_stack+0x7a/0x8d
[ 124.315153] [<c0103268>] ? dump_trace+0x78/0xa5
[ 124.315165] [<c0149609>] lock_acquire+0x45/0x5c
[ 124.315178] [<f85e70cf>] ? videobuf_dvb_find_frontend+0x16/0x3e [videobuf_dvb]
[ 124.315194] [<f85e70cf>] ? videobuf_dvb_find_frontend+0x16/0x3e [videobuf_dvb]
[ 124.315208] [<c0440b37>] mutex_lock_nested+0x35/0x275
[ 124.315222] [<f85e70cf>] ? videobuf_dvb_find_frontend+0x16/0x3e [videobuf_dvb]
[ 124.315237] [<f85e70cf>] videobuf_dvb_find_frontend+0x16/0x3e [videobuf_dvb]
[ 124.315254] [<f86ced7a>] cx88_dvb_bus_ctrl+0x22/0x9a [cx88_dvb]
[ 124.315273] [<f8e4982f>] dvb_frontend_open+0x14b/0x2ee [dvb_core]
[ 124.315293] [<f8e43173>] dvb_device_open+0xcf/0x185 [dvb_core]
[ 124.315307] [<c0194f15>] chrdev_open+0x14e/0x16c
[ 124.315320] [<c019056b>] __dentry_open+0x193/0x288
[ 124.315333] [<c044502f>] ? sub_preempt_count+0x81/0x8e
[ 124.315345] [<c01913a9>] nameidata_to_filp+0x42/0x50
[ 124.315357] [<c0194dc7>] ? cdev_put+0x1a/0x1a
[ 124.315369] [<c019c89b>] do_last+0x6db/0x6ed
[ 124.315381] [<c019c973>] path_openat+0xa1/0x2c2
[ 124.315393] [<c019cc40>] do_filp_open+0x21/0x5d
[ 124.315406] [<c044502f>] ? sub_preempt_count+0x81/0x8e
[ 124.315418] [<c04428ba>] ? _raw_spin_unlock+0x27/0x3d
[ 124.315432] [<c01a5a8f>] ? alloc_fd+0xb3/0xbe
[ 124.315444] [<c01914a5>] do_sys_open+0xee/0x167
[ 124.315456] [<c019153d>] sys_open+0x1f/0x27
[ 124.315468] [<c0442bf5>] syscall_call+0x7/0xb
[ 124.315480] [<c0440000>] ? schedule_timeout_interruptible+0x8/0x16
Software
=======
openSuSE 12.1, Tumbleweed
X.Org X Server 1.11.99.902 (1.12.0 RC 2), current git master
Kaffeine: 1.2.2 (Qt: 4.7.4, KDE: 4.7.2 (4.7.2) "release 5")
Hardware
========
AOpen i915GMm-hfs, Pentium-M Dothan (2GHz), 2GB RAM**
Hauppauge WinTV Nova-HD-S2
cu,
knut
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