Re: [PATCH 7/7] driver-core : convert semaphore to mutex in structclass

From: Jarek Poplawski
Date: Mon Jan 21 2008 - 16:14:17 EST


Dave Young wrote, On 01/21/2008 09:44 AM:
...
> I applied it in my kernel, built and run without warnings, but it need
> more testing.
> I will be very glad to see the test result about this if you could, thanks.

Bad news. (Alas I won't be able to check this today.)

=============================================
[ INFO: possible recursive locking detected ]
2.6.24-rc8 #5
---------------------------------------------
modprobe/536 is trying to acquire lock:
(&cls->mutex/1){--..}, at: [<c0217e43>] class_device_add+0x2c6/0x322

but task is already holding lock:
(&cls->mutex/1){--..}, at: [<c0217e43>] class_device_add+0x2c6/0x322

other info that might help us debug this:
2 locks held by modprobe/536:
#0: (&shost->scan_mutex){--..}, at: [<ce82795b>] __scsi_add_device+0x60/0xc9 [scsi_mod]
#1: (&cls->mutex/1){--..}, at: [<c0217e43>] class_device_add+0x2c6/0x322

stack backtrace:
Pid: 536, comm: modprobe Not tainted 2.6.24-rc8 #5
[<c0138edf>] __lock_acquire+0x962/0x10d4
[<c028be37>] _spin_unlock_irqrestore+0x34/0x39
[<c015e693>] kfree+0x87/0xad
[<c01380cb>] trace_hardirqs_on+0xba/0x15b
[<c01396c2>] lock_acquire+0x71/0x8b
[<c0217e43>] class_device_add+0x2c6/0x322
[<c028a87f>] mutex_lock_nested+0x92/0x2bc
[<c0217e43>] class_device_add+0x2c6/0x322
[<c0217e43>] class_device_add+0x2c6/0x322
[<c0217e43>] class_device_add+0x2c6/0x322
[<c01afd42>] kobject_get+0xf/0x13
[<c01afe68>] kobject_init+0x29/0x38
[<c0217f2c>] class_device_create+0x7d/0x9e
[<cebfe5b4>] sg_add+0x144/0x39f [sg]
[<c0217e71>] class_device_add+0x2f4/0x322
[<ce8289f7>] scsi_sysfs_add_sdev+0x64/0x1ac [scsi_mod]
[<ce840ece>] ata_scsi_dev_config+0x14/0x91 [libata]
[<ce826b5c>] scsi_probe_and_add_lun+0x9c0/0x9e0 [scsi_mod]
[<ce82795b>] __scsi_add_device+0x60/0xc9 [scsi_mod]
[<ce8279c2>] __scsi_add_device+0xc7/0xc9 [scsi_mod]
[<ce841401>] ata_scsi_scan_host+0xd3/0x26a [libata]
[<ce83e7e6>] ata_host_register+0x205/0x280 [libata]
[<ce83f430>] ata_interrupt+0x0/0x200 [libata]
[<ce83e8ec>] ata_host_activate+0x8b/0xf2 [libata]
[<ceb95504>] svia_init_one+0x2e2/0x511 [sata_via]
[<c01ca42c>] pci_match_device+0xa5/0xb6
[<ceb95222>] svia_init_one+0x0/0x511 [sata_via]
[<c01ca4e9>] pci_device_probe+0x40/0x5f
[<c02173ae>] driver_probe_device+0x7c/0x175
[<c02175ed>] __driver_attach+0xa2/0xa4
[<c02168dd>] bus_for_each_dev+0x3c/0x5a
[<c0217263>] driver_attach+0x16/0x1a
[<c021754b>] __driver_attach+0x0/0xa4
[<c0216bea>] bus_add_driver+0x72/0x1c0
[<c01ca642>] __pci_register_driver+0x56/0x89
[<c013f11d>] sys_init_module+0xf8/0x1891
[<ce83901f>] ata_port_start+0x0/0x65 [libata]
[<c01380cb>] trace_hardirqs_on+0xba/0x15b
[<c0102936>] syscall_call+0x7/0xb
=======================
scsi 2:0:0:0: Attached scsi generic sg1 type 0

Regards,
Jarek P.
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