Russell, Here is one more bug exposed by your patch. :) commit c817a67ecba7c3c2aaa104796d78f160af60920d Author: Russell King Date: Thu Jun 27 15:06:14 2013 +0100 kobject: delayed kobject release: help find buggy drivers [ 4.573351] INFO: trying to register non-static key. [ 4.573767] the code is fine but needs lockdep annotation. [ 4.574208] turning off the locking correctness validator. [ 4.574652] CPU: 1 PID: 345 Comm: trinity Not tainted 3.12.0-rc1 #76 [ 4.575155] 00000000 00000000 8d47fc4c 813a8643 8da4bc90 8d47fc88 81090483 814dc094 [ 4.575862] 8d47fc80 8106a187 00000006 8da4bc90 0000002a 00000002 8d47fcac 00000000 [ 4.576581] 8d47fcd4 8da4bc90 8d47fcd4 00000000 8d47fcb4 81091242 00000000 00000000 [ 4.576676] Call Trace: [ 4.576676] [<813a8643>] dump_stack+0x4b/0x66 [ 4.576676] [<81090483>] __lock_acquire.isra.21+0x183/0x8e0 [ 4.576676] [<8106a187>] ? sched_clock_cpu+0x117/0x130 [ 4.576676] [<81091242>] lock_acquire+0x72/0x90 [ 4.576676] [<81049380>] ? process_timeout+0x10/0x10 [ 4.576676] [<810493e9>] call_timer_fn+0x69/0xe0 [ 4.576676] [<81049380>] ? process_timeout+0x10/0x10 [ 4.576676] [<810495b1>] run_timer_softirq+0x151/0x180 [ 4.576676] [<810437e5>] __do_softirq+0xa5/0x160 [ 4.576676] [<8106a187>] ? sched_clock_cpu+0x117/0x130 [ 4.576676] [<8108d754>] ? tick_nohz_handler+0xd4/0xe0 [ 4.576676] [<810439b7>] irq_exit+0x47/0xa0 [ 4.576676] [<810279b5>] smp_apic_timer_interrupt+0x35/0x50 [ 4.576676] [<813af0f1>] apic_timer_interrupt+0x31/0x38 [ 4.576676] [<8110007b>] ? shrink_dentry_list+0x15b/0x420 [ 4.576676] [<8118da90>] ? do_raw_spin_lock+0x120/0x120 [ 4.576676] [<813adfe9>] ? _raw_spin_lock+0x49/0x70 [ 4.576676] [<81101154>] ? __d_lookup+0x94/0x1a0 [ 4.576676] [<81101154>] __d_lookup+0x94/0x1a0 [ 4.576676] [<811010c0>] ? __d_lookup_rcu+0x160/0x160 [ 4.576676] [<810f652d>] ? inode_permission+0x3d/0x50 [ 4.576676] [<810f5da0>] lookup_fast+0x180/0x250 [ 4.576676] [<810f75d3>] path_lookupat+0x573/0x650 [ 4.576676] [<810e4a19>] ? kmem_cache_alloc+0x39/0x130 [ 4.576676] [<8106a187>] ? sched_clock_cpu+0x117/0x130 [ 4.576676] [<810f63a0>] ? getname_flags+0x20/0xf0 [ 4.576676] [<810f76d1>] filename_lookup.isra.47+0x21/0x60 [ 4.576676] [<810f9fd9>] user_path_at_empty+0x49/0x70 [ 4.576676] [<810f1192>] ? cp_new_stat64+0xf2/0x110 [ 4.576676] [<810fa01a>] user_path_at+0x1a/0x20 [ 4.576676] [<810f0d84>] vfs_fstatat+0x44/0x90 [ 4.576676] [<810f1591>] SyS_lstat64+0x21/0x40 [ 4.576676] [<813aedec>] ? syscall_exit+0x8/0x21 [ 4.576676] [<813aede0>] syscall_call+0x7/0xb [ 4.576676] [<813a0000>] ? vsock_addr_init+0x20/0x20 [ 4.591703] kernel tried to execute NX-protected page - exploit attempt? (uid: 65534) [ 4.592335] BUG: unable to handle kernel paging request at 8da3b054 git bisect start 272b98c6455f00884f0350f775c5342358ebb73f v3.11 -- git bisect bad 57d730924d5cc2c3e280af16a9306587c3a511db # 18:27 23- Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip git bisect bad a9238741987386bb549d61572973c7e62b2a4145 # 18:32 21- Merge tag 'pci-v3.12-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci git bisect good 91121c103ae93ef117e58712786864270d7f488e # 19:11 5000+ staging: dwc2: make dwc2_core_params documentation more complete git bisect good 1d1fdd95df681f0c065d90ffaafa215a0e8825e2 # 20:37 5000+ Merge tag 'char-misc-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc git bisect bad d472d9d98b463dd7a04f2bcdeafe4261686ce6ab # 20:43 171- lockref: Relax in cmpxchg loop git bisect good e438ac9ade074932383bb00d51b8ded8a0ee164b # 00:05 5000+ OMAP: serial: Remove incorrect disabling of IER interrupt git bisect bad 36c27a655a531f16b5567066600f0ea7fcb973b4 # 00:15 793- w1: add attribute groups to struct w1_family_ops git bisect bad 13e2237f36874a7abef44b98969f399127b1917d # 00:19 63- v4l2: convert class code to use dev_groups git bisect bad 3499116b915e260b275c167a471e0e05bbe3f1d6 # 00:25 134- PTP: convert class code to use dev_groups git bisect bad 58b267d3e3f3ce87c3e559e4c330c8c03e905f5e # 00:34 574- dma: convert dma_devclass to use dev_groups git bisect good 899826f16a034f1ab6d23cd5b60cd113eaefad19 # 02:10 5000+ enclosure: convert class code to use dev_groups git bisect good ac3785d5c15922c8a4c6b9e050a5bc59895a6b9b # 03:03 5000+ c2port: convert class code to use bin_attrs in groups git bisect bad c817a67ecba7c3c2aaa104796d78f160af60920d # 03:09 118- kobject: delayed kobject release: help find buggy drivers git bisect good 7c42721fe0c58a848849b43ff558cf2fb86aa35a # 09:40 5000+ char: tile-srom: fix build error git bisect good 7c42721fe0c58a848849b43ff558cf2fb86aa35a # 19:35 10000+ char: tile-srom: fix build error git bisect good 7c42721fe0c58a848849b43ff558cf2fb86aa35a # 00:00 10000+ char: tile-srom: fix build error git bisect bad e62063d69911886a5a92c719d262a2a87e1e5b60 # 00:09 157- Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs git bisect bad a0cf1abc25ac197dd97b857c0f6341066a8cb1cf # 00:16 63- Add linux-next specific files for 20130927 Thanks, Fengguang