Hi Rostedt,

I got the below BUG and the first bad commit could be any of:

ce9bae55972b228cf7bac34350c4d2caf8ea0d0b
121aaee7b0a82605d33af200c7e9ebab6fd6e444
737223fbca3b1c91feb947c7f571b35749b743b6
45ad21ca5530efdca6a19e4a5ac5e7bd6e24f996
a695cb5816228f86576f5f5c6809fdf8ed382ece
6de58e6269cd0568ca5fbae14423914eff0f7811
ad909e21bbe69f1d39055d346540abd827190eca
0b85ffc293044393623059eda9904a7d5b644e36
f5eb5588262cab7232ed1d77cf612b327db50767
f1affcaaa861f27752a769f889bf1486ebd301fe
f4e781c0a89d5810729772290441ac7d61f321ec
12883efb670c28dff57dcd7f4f995a1ffe153b2d
55034cd6e648155393b0d665eef76b38d49ad6bf
153e8ed913b022d2003866a848af9fadc041403f

We cannot bisect more due to broken builds.

[    3.240151] PASSED
[    3.242098] Testing tracer branch: 
[    3.350189] BUG: unable to handle kernel NULL pointer dereference at   (null)
[    3.358885] IP: [<c112ccbb>] ring_buffer_entries+0x14/0x39
[    3.360000] *pde = 00000000 
[    3.360000] Oops: 0000 [#1] PREEMPT 
[    3.360000] Modules linked in:
[    3.360000] CPU: 0 PID: 1 Comm: swapper Not tainted 3.10.0-rc3-00105-g854f5c1 #2
[    3.360000] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[    3.360000] task: cbc58000 ti: cbc5a000 task.ti: cbc5a000
[    3.360000] EIP: 0060:[<c112ccbb>] EFLAGS: 00010046 CPU: 0
[    3.360000] EIP is at ring_buffer_entries+0x14/0x39
[    3.360000] EAX: 00000000 EBX: 00000000 ECX: 00000044 EDX: c113f95c
[    3.360000] ESI: c2062a80 EDI: cbc5befc EBP: cbc5bec4 ESP: cbc5bec4
[    3.360000]  DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068
[    3.360000] CR0: 8005003b CR2: 00000000 CR3: 01fb1000 CR4: 000006d0
[    3.360000] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[    3.360000] DR6: ffff0ff0 DR7: 00000400
[    3.360000] Stack:
[    3.360000]  cbc5bef0 c1135a9d c11383c1 00000246 00000246 c2062a80 00000246 c1eae260
[    3.360000]  00000000 c1eae260 c2062a80 cbc5bf0c c113f95c 00000006 00000000 c1eae260
[    3.360000]  c1eae1e8 00000000 cbc5bf24 c1140372 c1bc30da c1bc33d6 00000001 c1eddd7f
[    3.360000] Call Trace:
[    3.360000]  [<c1135a9d>] trace_test_buffer+0x5a/0x29e
[    3.360000]  [<c11383c1>] ? tracing_stop+0x36/0x1d2
[    3.360000]  [<c113f95c>] trace_selftest_startup_branch+0x93/0x115
[    3.360000]  [<c1140372>] register_tracer+0x277/0x47d
[    3.360000]  [<c1eddd7f>] ? init_annotated_branch_stats+0x61/0x61
[    3.360000]  [<c1eddde6>] init_branch_tracer+0x67/0x77
[    3.360000]  [<c10002b3>] do_one_initcall+0x19e/0x31f
[    3.360000]  [<c10b08c8>] ? spin_unlock_irqrestore.isra.55+0xd7/0x10d
[    3.360000]  [<c1eb38a2>] kernel_init_freeable+0x3de/0x561
[    3.360000]  [<c1eb2521>] ? loglevel+0x55/0x55
[    3.360000]  [<c1a345bc>] kernel_init+0x1e/0x206
[    3.360000]  [<c1a689f7>] ret_from_kernel_thread+0x1b/0x28
[    3.360000]  [<c1a3459e>] ? rest_init+0x10e/0x10e
[    3.360000] Code: 83 05 c8 1b 06 c2 01 83 15 cc 1b 06 c2 00 8b 40 48 eb 02 31 c0 5d c3 55 8b 40 24 83 05 d8 1b 06 c2 01 89 e5 83 15 dc 1b 06 c2 00 <8b> 00 e8 0d fe ff ff 83 05 d0 1b 06 c2 01 83 15 d4 1b 06 c2 00
[    3.360000] EIP: [<c112ccbb>] ring_buffer_entries+0x14/0x39 SS:ESP 0068:cbc5bec4
[    3.360000] CR2: 0000000000000000
[    3.360000] ---[ end trace 066877a51305f5c2 ]---

git bisect start 854f5c142a3bed29985e281000ab5ff9e5913065 v3.9 --
git bisect  bad 73287a43cc79ca06629a88d1a199cd283f42456a  #     0  2013-05-29 17:31:04  Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
git bisect  bad 5d434fcb255dec99189f1c58a06e4f56e12bf77d  #     0  2013-05-29 17:37:48  Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
git bisect good 507ffe4f3840ac24890a8123c702cf1b7fe4d33c  #    10  2013-05-29 17:55:33  Merge tag 'tty-3.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
git bisect good 4a7b4d2360175f67ab2c58effeeb8362a3057c25  #    10  2013-05-29 18:07:41  x86: pageattr-test: remove srandom32 call
git bisect  bad 46d9be3e5eb01f71fc02653755d970247174b400  #     3  2013-05-29 18:17:09  Merge branch 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
git bisect  bad 8ded8d4e4facab78acf616bc34085ddd15c2c21c  #     0  2013-05-29 18:26:21  Merge tag 'regulator-v3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator
git bisect good 75f01f949902db68b7937dfbae71b0b46a398161  #    10  2013-05-29 18:33:41  Merge remote-tracking branch 'regulator/topic/mc13892' into v3.9-rc8
git bisect  bad f1943977e6648c1d42a78eda4ba4429a2bc0b786  #     0  2013-05-29 18:38:29  tracing: Get rid of unneeded key calculation in ftrace_hash_move()
git bisect  bad 417944c4c7a0f657158d0515f3b8e8c043fd788f  #     0  2013-05-29 18:57:44  tracing: Add a way to soft disable trace events
git bisect good 575380da8b46969a2c6a7e14a51056a63b30fe2e  #    10  2013-05-29 19:28:44  tracing: Only clear trace buffer on module unload if event was traced
git bisect  bad 57d01ad09721fb7719c4c8c72b434398186f35a0  #     0  2013-05-29 19:45:21  tracing: Fix comments for ftrace_event_file/call flags
git bisect  bad 09ae72348eccb60e304cf8ce94653f4a78fcd407  #     0  2013-05-29 20:06:00  tracing: Add trace_puts() for even faster trace_printk() tracing
git bisect good 22cffc2bb4a50d8c56f03c56f9f19dea85b78e30  #    10  2013-05-29 21:36:32  tracing: Enable snapshot when any latency tracer is enabled
git bisect  bad 153e8ed913b022d2003866a848af9fadc041403f  #     0  2013-05-29 22:01:44  tracing: Fix the branch tracer that broke with buffer change

Thanks,
Fengguang