Hi Al, I got the below dmesg and the first bad commit is commit 3d54406d3c64c0e7e092f8299c460ebe0aea9795 Author: Al Viro AuthorDate: Thu Mar 20 21:10:51 2014 -0400 Commit: Al Viro CommitDate: Thu Mar 20 21:10:51 2014 -0400 switch mnt_hash to hlist Cc: stable@vger.kernel.org Signed-off-by: Al Viro =================================================== PARENT COMMIT NOT CLEAN. LOOK OUT FOR WRONG BISECT! =================================================== +------------------------------------------------------+------------+------------+------------+ | | 6a92faa1d6 | 3d54406d3c | 77a67cc34b | +------------------------------------------------------+------------+------------+------------+ | boot_successes | 429 | 41 | 12 | | boot_failures | 4 | 44 | 17 | | BUG:unable_to_handle_kernel_NULL_pointer_dereference | 4 | 4 | | | Oops | 4 | 44 | 17 | | RIP:rapl_pmu_init | 4 | | | | Kernel_panic-not_syncing:Fatal_exception | 4 | 44 | 17 | | backtrace:rapl_pmu_init | 4 | | | | backtrace:kernel_init_freeable | 4 | | | | RIP:umount_tree | 0 | 4 | | | backtrace:do_group_exit | 0 | 3 | | | backtrace:SyS_exit_group | 0 | 3 | | | backtrace:unshare_nsproxy_namespaces | 0 | 1 | | | backtrace:SyS_unshare | 0 | 1 | | | BUG:unable_to_handle_kernel_paging_request | 0 | 40 | 17 | | RIP:dentry_kill | 0 | 40 | 17 | | backtrace:namespace_unlock | 0 | 40 | 17 | | backtrace:SyS_umount | 0 | 40 | 17 | +------------------------------------------------------+------------+------------+------------+ [ 4.406852] Freeing unused kernel memory: 1832K (ffff880001a36000 - ffff880001c00000) [ 4.427969] Freeing unused kernel memory: 876K (ffff880001f25000 - ffff880002000000) Kernel tests: Boot OK! [ 531.406767] BUG: unable to handle kernel paging request at ffffffff81176112 [ 531.408103] IP: [] dentry_kill.isra.25+0xd0/0x2cb [ 531.408103] PGD 2015067 PUD 2016063 PMD 10001e1 [ 531.408103] Oops: 0003 [#1] [ 531.408103] Modules linked in: [ 531.408103] CPU: 0 PID: 363 Comm: umount Not tainted 3.14.0-rc7-00038-g3d54406 #39 [ 531.408103] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 531.408103] task: ffff88000e3b7320 ti: ffff88000e376000 task.ti: ffff88000e376000 [ 531.408103] RIP: 0010:[] [] dentry_kill.isra.25+0xd0/0x2cb [ 531.408103] RSP: 0018:ffff88000e377ea0 EFLAGS: 00010202 [ 531.408103] RAX: ffffffff81176112 RBX: ffff88000efd1210 RCX: ffff88000e7c9ab8 [ 531.408103] RDX: ffff88000e7c9ab8 RSI: ffffffff8117f37f RDI: ffff88000efd1210 [ 531.408103] RBP: ffff88000e377eb8 R08: 00000000ffffffff R09: 0000000000000000 [ 531.408103] R10: 0000000000737470 R11: ffff88000e3a7025 R12: ffff88000e7c9b90 [ 531.408103] R13: ffff88000ec075d0 R14: 0000000000000000 R15: ffff88000e7c9a80 [ 531.408103] FS: 00007f86c2759700(0000) GS:ffffffff82030000(0000) knlGS:0000000000000000 [ 531.408103] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 531.408103] CR2: ffffffff81176112 CR3: 000000000e273000 CR4: 00000000000006f0 [ 531.408103] Stack: [ 531.408103] ffff88000efd1210 ffff88000e7c9b90 ffff88000e7c9a80 ffff88000e377ed0 [ 531.408103] ffffffff811779c8 ffff88000e7c9b90 ffff88000e377ee8 ffffffff81168638 [ 531.408103] ffff88000e7c9a80 ffff88000e377f08 ffffffff8117fda2 ffff88000e7c9aa0 [ 531.408103] Call Trace: [ 531.408103] [] dput+0x184/0x1b8 [ 531.408103] [] path_put+0x18/0x31 [ 531.408103] [] namespace_unlock+0xb8/0xd1 [ 531.408103] [] SyS_umount+0x4a4/0x4f2 [ 531.408103] [] ? vm_munmap+0x5d/0x72 [ 531.408103] [] system_call_fastpath+0x16/0x1b [ 531.408103] Code: ff 05 23 cf 3c 01 e8 dc dd ff ff 48 ff 05 1f cf 3c 01 48 ff 05 00 af 3c 01 48 8b 83 98 00 00 00 48 8b 93 90 00 00 00 48 89 42 08 <48> 89 10 48 b8 00 01 10 00 00 00 ad de 48 89 83 90 00 00 00 81 [ 531.408103] RIP [] dentry_kill.isra.25+0xd0/0x2cb [ 531.408103] RSP [ 531.408103] CR2: ffffffff81176112 [ 531.408103] ---[ end trace 2d4bf249e005ed27 ]--- [ 531.408103] Kernel panic - not syncing: Fatal exception git bisect start 77a67cc34b63c0f868f0bb66e7c23dd2743b2d97 dcb99fd9b08cfe1afe426af4d8d3cbc429190f15 -- git bisect bad fca1d772b6e12a5e5e3e5749f8b06650aeecbc6c # 05:49 0- 13 Merge 'vfs/untested-mnt_hash' into devel-cairo-x86_64-201403211021 git bisect good 92fef99b88a854a6dbfd25fb1c4305662a182452 # 05:49 85+ 0 0day base guard for 'devel-cairo-x86_64-201403211021' git bisect good 8a21d9f63dd47485964b930af41304d88dee0e9b # 05:53 30+ 1 Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus git bisect good ea1cd65a648bd98ff9d028a647462d28313aadfd # 05:59 30+ 1 Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip git bisect good 887843961c4b4681ee993c36d4997bf4b4aa8253 # 06:04 30+ 2 mm: fix bad rss-counter if remap_file_pages raced migration git bisect good 8cefb970aa3b94377554d5083611768ff257ce19 # 06:04 85+ 0 resizable namespace.c hashes git bisect bad 3d54406d3c64c0e7e092f8299c460ebe0aea9795 # 06:04 0- 44 switch mnt_hash to hlist git bisect good 6a92faa1d647d78ec54506d783c5a7ce503b4843 # 06:11 31+ 4 smarter propagate_mnt() # first bad commit: [3d54406d3c64c0e7e092f8299c460ebe0aea9795] switch mnt_hash to hlist git bisect good 6a92faa1d647d78ec54506d783c5a7ce503b4843 # 06:16 93+ 4 smarter propagate_mnt() git bisect bad 77a67cc34b63c0f868f0bb66e7c23dd2743b2d97 # 06:16 0- 17 0day head guard for 'devel-cairo-x86_64-201403211021' git bisect good 774868c7094d35b4518be3d0e654de000a5d11fc # 06:32 93+ 0 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip git bisect good 098bc161bfc7697f7e2ca15400f13ca1ac60e9dd # 06:54 93+ 0 Add linux-next specific files for 20140324 This script may reproduce the error. ----------------------------------------------------------------------------- #!/bin/bash kernel=$1 initrd=yocto-minimal-x86_64.cgz wget --no-clobber https://github.com/fengguang/reproduce-kernel-bug/blob/master/initrd/$initrd kvm=( qemu-system-x86_64 -cpu kvm64 -enable-kvm -kernel $kernel -initrd $initrd -smp 2 -m 256M -net nic,vlan=0,macaddr=00:00:00:00:00:00,model=virtio -net user,vlan=0 -net nic,vlan=1,model=e1000 -net user,vlan=1 -boot order=nc -no-reboot -watchdog i6300esb -serial stdio -display none -monitor null ) append=( debug sched_debug apic=debug ignore_loglevel sysrq_always_enabled panic=10 prompt_ramdisk=0 earlyprintk=ttyS0,115200 console=ttyS0,115200 console=tty0 vga=normal root=/dev/ram0 rw ) "${kvm[@]}" --append "${append[*]}" ----------------------------------------------------------------------------- Thanks, Fengguang