Hi all,

I got the below trace that's triggered by this WARN:

        /*
         * Oi! Can't be having __GFP_FS allocations with IRQs disabled.
         */
        if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))

[   74.483773] machine restart
[   74.486051] ------------[ cut here ]------------
[   74.487204] WARNING: at /c/kernel-tests/src/linux/kernel/lockdep.c:2739 lockdep_trace_alloc+0xc3/0xd0()
[   74.487760] Hardware name: Bochs
[   74.487760] Pid: 371, comm: reboot Not tainted 3.5.0-rc3 #3751
[   74.487760] Call Trace:
[   74.487760]  [<41056898>] warn_slowpath_common+0x68/0xa0
[   74.487760]  [<410a3d03>] ? lockdep_trace_alloc+0xc3/0xd0
[   74.487760]  [<410a3d03>] ? lockdep_trace_alloc+0xc3/0xd0
[   74.487760]  [<4105697d>] warn_slowpath_null+0x1d/0x20
[   74.487760]  [<410a3d03>] lockdep_trace_alloc+0xc3/0xd0
[   74.487760]  [<411015c9>] kmem_cache_alloc+0x29/0x120
[   74.487760]  [<4141442b>] ? bus_find_device+0x5b/0x70
[   74.487760]  [<413adfa1>] ? pci_get_subsys+0x31/0x80
[   74.487760]  [<413adfa1>] pci_get_subsys+0x31/0x80
[   74.487760]  [<413ae00b>] pci_get_device+0x1b/0x20
[   74.487760]  [<41043653>] mach_reboot_fixups+0x33/0x50
[   74.487760]  [<4103e108>] native_machine_emergency_restart+0x98/0x200
[   74.487760]  [<4103de08>] ? native_machine_shutdown+0x88/0x120
[   74.487760]  [<4103dd72>] native_machine_restart+0x32/0x40
[   74.487760]  [<4103dfc9>] machine_restart+0x9/0x10
[   74.487760]  [<4106b0c3>] kernel_restart+0x33/0x50
[   74.487760]  [<4106b309>] sys_reboot+0x149/0x1c0
[   74.487760]  [<410850f7>] ? sched_clock_cpu+0xe7/0x190
[   74.487760]  [<410eb503>] ? handle_pte_fault+0x73/0x740
[   74.487760]  [<410a397b>] ? trace_hardirqs_off+0xb/0x10
[   74.487760]  [<41085335>] ? local_clock+0x65/0x70
[   74.487760]  [<4109ff5a>] ? lock_release_holdtime.part.24+0x7a/0xe0
[   74.487760]  [<41046938>] ? do_page_fault+0x178/0x3e0
[   74.487760]  [<410467c0>] ? vmalloc_sync_all+0x120/0x120
[   74.487760]  [<41079716>] ? up_read+0x16/0x30
[   74.487760]  [<41046938>] ? do_page_fault+0x178/0x3e0
[   74.487760]  [<4110181a>] ? kmem_cache_free+0xda/0xe0
[   74.487760]  [<41105f00>] ? do_sys_open+0x150/0x1a0
[   74.487760]  [<41105f00>] ? do_sys_open+0x150/0x1a0
[   74.487760]  [<41b0933e>] ? restore_all+0xf/0xf
[   74.487760]  [<410467c0>] ? vmalloc_sync_all+0x120/0x120
[   74.487760]  [<410a3844>] ? trace_hardirqs_on_caller+0xf4/0x180
[   74.487760]  [<4137ecc0>] ? trace_hardirqs_on_thunk+0xc/0x10
[   74.487760]  [<41b09305>] syscall_call+0x7/0xb

Thanks,
Fengguang