Greetings, 0day kernel testing robot got the below dmesg and the first bad commit is git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git rcu_tasks.2014.07.28d commit bd14ddc45614b61210fdf0ee4e94152948dd9d5e Author: Paul E. McKenney AuthorDate: Mon Jul 28 12:41:25 2014 -0700 Commit: Paul E. McKenney CommitDate: Mon Jul 28 14:57:56 2014 -0700 rcu: Make RCU-tasks track exiting tasks This commit adds synchronization with exiting tasks, so that RCU-tasks avoids waiting on tasks that no longer exist. Signed-off-by: Paul E. McKenney Conflicts: kernel/rcu/update.c +--------------------------------------------------------------------------+------------+------------+ | | 4e73c5aafb | bd14ddc456 | +--------------------------------------------------------------------------+------------+------------+ | boot_successes | 60 | 0 | | boot_failures | 0 | 20 | | BUG:sleeping_function_called_from_invalid_context_at_kernel/rcu/update.c | 0 | 20 | | backtrace:do_group_exit | 0 | 20 | | backtrace:SyS_exit_group | 0 | 20 | | backtrace:do_exit | 0 | 0 | +--------------------------------------------------------------------------+------------+------------+ [ 4.702913] Freeing unused kernel memory: 2000K (ffff88000200c000 - ffff880002200000) [ 4.730428] Freeing unused kernel memory: 1880K (ffff88000262a000 - ffff880002800000) [ 4.770934] random: init urandom read with 6 bits of entropy available [ 4.793994] BUG: sleeping function called from invalid context at kernel/rcu/update.c:871 [ 4.802080] in_atomic(): 1, irqs_disabled(): 0, pid: 94, name: hostname [ 4.808864] CPU: 0 PID: 94 Comm: hostname Not tainted 3.16.0-rc1-00010-gbd14ddc #1 [ 4.814520] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 [ 4.821278] ffff88000f2acac0 ffff88001322fe88 ffffffff81fdcc15 ffff88000f2acad0 [ 4.829295] ffff88001322fe98 ffffffff810cc549 ffff88001322feb0 ffffffff811099f9 [ 4.837254] ffff88000f2ad0d8 ffff88001322fec0 ffffffff81110a01 ffff88001322ff38 [ 4.845685] Call Trace: [ 4.849022] [] dump_stack+0x85/0xba [ 4.853129] [] __might_sleep+0x129/0x180 [ 4.857319] [] exit_rcu_tasks+0x29/0xa0 [ 4.861615] [] exit_rcu+0x11/0x20 [ 4.865672] [] do_exit+0xa05/0xfc0 [ 4.870864] [] do_group_exit+0x46/0x130 [ 4.875191] [] SyS_exit_group+0x17/0x20 [ 4.878693] [] system_call_fastpath+0x16/0x1b [ 5.081134] init: Failed to create pty - disabling logging for job [ 5.083491] init: Temporary process spawn error: No such file or directory [ 5.112668] init: Failed to create pty - disabling logging for job git bisect start d4762699d270faa2e5f8cc9b4a1feefb98270e5b 64aa90f26c06e1cb2aacfb98a7d0eccfbd6c1a91 -- git bisect good c34f8002be490ebe4490ed028648598c8067fff7 # 10:55 16+ 0 Merge 'skn/cacheinfo' into devel-hourly-2014072909 git bisect good 27df6032094f4633a974397e845f76a6ed00bf89 # 10:58 16+ 0 Merge 'jolsa-perf/perf/ctf_convert_4' into devel-hourly-2014072909 git bisect good 93bb3907de114a5ada548126cdd99475fd2b5ae8 # 11:27 16+ 0 Merge 'jcmvbkbc-xtensa/xtensa-debug' into devel-hourly-2014072909 git bisect good 8d443796938e40aeedf7e9b38d56729fc3070d18 # 12:30 16+ 0 Merge 'wireless-testing/master' into devel-hourly-2014072909 git bisect good e45ccc6c7f65c2d6823eaf4c082417c455b9af4b # 12:38 16+ 0 Merge 'robclark/msm-next' into devel-hourly-2014072909 git bisect bad 21fa7826ce4c9938067972a47d8fa8fdba2805a3 # 12:41 0- 16 Merge 'rcu/rcu/rcu_tasks' into devel-hourly-2014072909 git bisect good 41d8e02382e1e79c17a78c0898bc938531000716 # 13:05 20+ 0 rcutorture: Add torture tests for RCU-tasks git bisect good 4e73c5aafbe9108c83de0f8f5294e6ccad2e29c3 # 13:10 20+ 0 rcu: Add stall-warning checks for RCU-tasks git bisect bad ebc6436166ae583e6db906eb7ffdb1c198921380 # 13:21 0- 4 rcu: Improve RCU-tasks energy efficiency git bisect bad bd14ddc45614b61210fdf0ee4e94152948dd9d5e # 13:40 0- 20 rcu: Make RCU-tasks track exiting tasks # first bad commit: [bd14ddc45614b61210fdf0ee4e94152948dd9d5e] rcu: Make RCU-tasks track exiting tasks git bisect good 4e73c5aafbe9108c83de0f8f5294e6ccad2e29c3 # 13:45 60+ 0 rcu: Add stall-warning checks for RCU-tasks git bisect bad d4762699d270faa2e5f8cc9b4a1feefb98270e5b # 14:30 0- 11 0day head guard for 'devel-hourly-2014072909' git bisect good 31dab719fa50cf56d56d3dc25980fecd336f6ca8 # 14:38 60+ 0 Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 git bisect good e40cff4a7990e5d73eaad0a2f2593fe725e24cdd # 15:26 60+ 0 Add linux-next specific files for 20140728 This script may reproduce the error. ---------------------------------------------------------------------------- #!/bin/bash kernel=$1 kvm=( qemu-system-x86_64 -cpu kvm64 -enable-kvm -kernel $kernel -m 320 -smp 2 -net nic,vlan=1,model=e1000 -net user,vlan=1 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -serial stdio -display none -monitor null ) append=( hung_task_panic=1 earlyprintk=ttyS0,115200 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 panic=10 softlockup_panic=1 nmi_watchdog=panic prompt_ramdisk=0 console=ttyS0,115200 console=tty0 vga=normal root=/dev/ram0 rw drbd.minor_count=8 ) "${kvm[@]}" --append "${append[*]}" ---------------------------------------------------------------------------- Thanks, Fengguang _______________________________________________ LKP mailing list LKP(a)linux.intel.com