Greetings, I got the below dmesg and the first bad commit is commit 911af505ef407c2511106c224dd640f882f0f590 Author: Paul E. McKenney Date: Mon Feb 11 10:23:27 2013 -0800 rcu: Provide compile-time control for no-CBs CPUs Currently, the only way to specify no-CBs CPUs is via the rcu_nocbs kernel command-line parameter. This is inconvenient in some cases, particularly for randconfig testing, so this commit adds a new set of kernel configuration parameters. CONFIG_RCU_NOCB_CPU_NONE (the default) retains the old behavior, CONFIG_RCU_NOCB_CPU_ZERO offloads callback processing from CPU 0 (along with any other CPUs specified by the rcu_nocbs boot-time parameter), and CONFIG_RCU_NOCB_CPU_ALL offloads callback processing from all CPUs. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney [ 0.000000] Checking if this processor honours the WP bit even in supervisor mode...Ok. [ 0.000000] SLUB: HWalign=128, Order=0-3, MinObjects=0, CPUs=2, Nodes=1 [ 0.000000] Hierarchical RCU implementation. [ 0.000000] [ 0.000000] [ 0.000000] [ 0.000000] ------------[ cut here ]------------ [ 0.000000] WARNING: at /c/kernel-tests/src/linux/mm/nobootmem.c:215 ___alloc_bootmem_nopanic.constprop.5+0x79/0x15f() [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.10.0-rc1-00035-g297e580 #40 [ 0.000000] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 0.000000] 00000000 00000000 c1a71ef8 c1588367 c1a71f20 c104d6d0 c199e148 c19b2567 [ 0.000000] 000000d7 c1cec5a5 c1cec5a5 00000001 00000001 00000000 c1a71f30 c104d709 [ 0.000000] 00000009 00000000 c1a71f64 c1cec5a5 00000000 00000000 00000000 c1ef260a [ 0.000000] Call Trace: [ 0.000000] [] dump_stack+0x16/0x18 [ 0.000000] [] warn_slowpath_common+0x74/0x8b [ 0.000000] [] ? ___alloc_bootmem_nopanic.constprop.5+0x79/0x15f [ 0.000000] [] ? ___alloc_bootmem_nopanic.constprop.5+0x79/0x15f [ 0.000000] [] warn_slowpath_null+0x22/0x24 [ 0.000000] [] ___alloc_bootmem_nopanic.constprop.5+0x79/0x15f [ 0.000000] [] ___alloc_bootmem.constprop.4+0xe/0x49 [ 0.000000] [] ? printk+0x3d/0x3f [ 0.000000] [] __alloc_bootmem+0x8/0xa [ 0.000000] [] alloc_bootmem_cpumask_var+0x17/0x1c [ 0.000000] [] rcu_init+0xb9/0x309 [ 0.000000] [] ? perf_event_init+0x173/0x17a [ 0.000000] [] start_kernel+0x22d/0x453 [ 0.000000] [] ? repair_env_string+0x97/0x97 [ 0.000000] [] i386_start_kernel+0x90/0x94 [ 0.000000] ---[ end trace 5b01275a6144debd ]--- git bisect start 4237c09a63906b980741725da63f85e454caec02 v3.9 -- git bisect bad 73287a43cc79ca06629a88d1a199cd283f42456a # 0 2013-06-03 15:02:18 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next git bisect bad 5d434fcb255dec99189f1c58a06e4f56e12bf77d # 0 2013-06-03 15:08:57 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial git bisect good 507ffe4f3840ac24890a8123c702cf1b7fe4d33c # 10 2013-06-03 15:21:41 Merge tag 'tty-3.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty git bisect good 4a7b4d2360175f67ab2c58effeeb8362a3057c25 # 10 2013-06-03 15:28:44 x86: pageattr-test: remove srandom32 call git bisect good 46d9be3e5eb01f71fc02653755d970247174b400 # 10 2013-06-03 16:30:29 Merge branch 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq git bisect bad e0972916e8fe943f342b0dd1c9d43dbf5bc261c2 # 0 2013-06-03 16:34:11 Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip git bisect good 457d1772f1c1bcf37b2ae7fc8f1d6f303d1d5cf9 # 10 2013-06-03 16:52:58 uprobes/tracing: Generalize struct uprobe_trace_entry_head git bisect good 56847d857cb0c3ee78c22ce776a26f88d9ffd4d4 # 10 2013-06-03 17:45:40 Merge branch 'akpm' (incoming from Andrew) git bisect bad 8fcfae31719c0a6c03f2cf63f815b46d378d8be4 # 0 2013-06-03 17:49:28 Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu git bisect bad 8b425aa8f1acfe48aed919c7aadff2ed290fe969 # 0 2013-06-03 17:53:00 rcu: Rename n_nocb_gp_requests to need_future_gp git bisect bad a488985851cf2facd2227bd982cc2c251df56268 # 0 2013-06-03 17:56:38 rcu: Distinguish "rcuo" kthreads by RCU flavor git bisect bad dae6e64d2bcfd4b06304ab864c7e3a4f6b5fedf4 # 0 2013-06-03 18:00:10 rcu: Introduce proper blocking to no-CBs kthreads GP waits git bisect bad 911af505ef407c2511106c224dd640f882f0f590 # 0 2013-06-03 18:03:42 rcu: Provide compile-time control for no-CBs CPUs git bisect good 34ed62461ae4970695974afb9a60ac3df0086830 # 10 2013-06-03 18:09:43 rcu: Remove restrictions on no-CBs CPUs git bisect good 34ed62461ae4970695974afb9a60ac3df0086830 # 38 2013-06-03 18:12:45 rcu: Remove restrictions on no-CBs CPUs git bisect bad 297e5804fbed91ac58027d04e033540681763283 # 0 2013-06-03 18:13:19 exynos4-is: Add isp_dbg() macro git bisect good 6318c0ec14d5f7aea22987223e1a99dbda7b1fd0 # 30 2013-06-03 18:49:20 Add linux-next specific files for 20130603 Thanks, Fengguang