Hi Andy, FYI, one more BUG message for commit commit d07c7f1ed61789e175fa975134855be32263be2c Author: Andy Lutomirski AuthorDate: Tue Jul 15 18:34:20 2014 -0700 Commit: Andy Lutomirski CommitDate: Wed Jul 16 10:01:27 2014 -0700 x86,kaslr: Use MSR_KVM_GET_RNG_SEED for KASLR if available It's considerably better than any of the alternatives on KVM. Rather than reinventing all of the cpu feature query code, this fixes native_cpuid to work in PIC objects. I haven't combined it with boot/cpuflags.c's cpuid implementation: including asm/processor.h from boot/cpuflags.c results in a flood of unrelated errors, and fixing it might be messy. Signed-off-by: Andy Lutomirski =================================================== PARENT COMMIT NOT CLEAN. LOOK OUT FOR WRONG BISECT! =================================================== Attached dmesg for the parent commit, too, to help confirm whether it is a noise error. +----------------------------------------------------------+------------+------------+------------------+ | | c6f07a6360 | d07c7f1ed6 | v3.16-rc5_071701 | +----------------------------------------------------------+------------+------------+------------------+ | boot_successes | 1139 | 200 | 11 | | boot_failures | 61 | 100 | 10 | | BUG:kernel_boot_hang | 61 | 56 | 6 | | BUG:unable_to_handle_kernel_NULL_pointer_dereference | 0 | 44 | 4 | | Oops | 0 | 44 | 4 | | RIP:__free_pages_bootmem | 0 | 44 | 4 | | Kernel_panic-not_syncing:Attempted_to_kill_the_idle_task | 0 | 44 | 4 | | backtrace:free_all_bootmem | 0 | 44 | 4 | | backtrace:mem_init | 0 | 44 | 4 | +----------------------------------------------------------+------------+------------+------------------+ [ 0.000000] Dentry cache hash table entries: 65536 (order: 7, 524288 bytes) [ 0.000000] Inode-cache hash table entries: 32768 (order: 6, 262144 bytes) [ 0.000000] xsave: enabled xstate_bv 0x7, cntxt size 0x0 [ 0.000000] BUG: unable to handle kernel NULL pointer dereference at 00000000000006fc [ 0.000000] IP: [] __free_pages_bootmem+0x21/0x9d [ 0.000000] PGD 0 [ 0.000000] Oops: 0002 [#1] [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 3.16.0-rc5-00004-gd07c7f1 #1 [ 0.000000] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 0.000000] task: ffffffff81a1a4c0 ti: ffffffff81a00000 task.ti: ffffffff81a00000 [ 0.000000] RIP: 0010:[] [] __free_pages_bootmem+0x21/0x9d [ 0.000000] RSP: 0000:ffffffff81a03ed8 EFLAGS: 00010012 [ 0.000000] RAX: 0000000000000734 RBX: 0000000000000010 RCX: 0000000000000004 [ 0.000000] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00000000000006fc [ 0.000000] RBP: ffffffff81a03f00 R08: 000000000000000f R09: 0000000000000010 [ 0.000000] R10: 000000000000001c R11: 000000000009f000 R12: 0000000000000099 [ 0.000000] R13: 0000000000000020 R14: 000000000000000a R15: ffffffff81c9b120 [ 0.000000] FS: 0000000000000000(0000) GS:ffffffff81a25000(0000) knlGS:0000000000000000 [ 0.000000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.000000] CR2: 00000000000006fc CR3: 0000000001a15000 CR4: 00000000000406a0 [ 0.000000] Stack: [ 0.000000] ffffffff81cb6bd3 0000000000000000 ffffffff81d19940 ffff880013ffc140 [ 0.000000] ffffffff81d200a0 ffffffff81a03f38 ffffffff81cb6de3 0000000000000000 [ 0.000000] 0000000000010000 0000000000099000 0000000200000000 ffffffffffffffff [ 0.000000] Call Trace: [ 0.000000] [] ? __free_memory_core+0xa2/0xb9 [ 0.000000] [] free_all_bootmem+0x51/0xd2 [ 0.000000] [] mem_init+0xe/0x21 [ 0.000000] [] start_kernel+0x1eb/0x4ea [ 0.000000] [] ? set_init_arg+0x55/0x55 [ 0.000000] [] x86_64_start_reservations+0x2a/0x2c [ 0.000000] [] x86_64_start_kernel+0x172/0x181 [ 0.000000] Code: 89 e5 5d c3 55 48 89 e5 5d c3 40 88 f1 41 b9 01 00 00 00 41 d3 e1 0f 18 0f 31 d2 48 89 f8 45 8d 41 ff eb 15 48 83 c0 38 0f 18 08 <0f> ba 70 c8 0a c7 40 e4 00 00 00 00 ff c2 41 39 d0 77 e6 4d 6b [ 0.000000] RIP [] __free_pages_bootmem+0x21/0x9d [ 0.000000] RSP [ 0.000000] CR2: 00000000000006fc [ 0.000000] ---[ end trace 87d1642ee2ad5638 ]--- [ 0.000000] Kernel panic - not syncing: Attempted to kill the idle task! git bisect start 5e60c2af7a8bde5cfaee8ffd77cfc5b62db0a04e 1795cd9b3a91d4b5473c97f491d63892442212ab -- git bisect good bc1f2f93f68bccd988af7e6f73384860ac241b78 # 07:33 300+ 123 Merge 'socfpga-nex/nios2-upstream' into devel-hourly-2014071701 git bisect bad 0d7e1ca40ef16fce5297579121717fc793761b38 # 07:33 0- 123 Merge 'dynticks/nohz/sysidle' into devel-hourly-2014071701 git bisect good 33c13bf2487a42efa1ac9bcce5623ab74a375c93 # 07:37 300+ 30 Merge 'ubifs/linux-next' into devel-hourly-2014071701 git bisect good 1032f73a32951d7f14ed7fdadedb0fef3c6d0f49 # 07:43 300+ 0 Merge 'spi/for-next' into devel-hourly-2014071701 git bisect bad 1f2859f0786338fe4c2a18ea518a5b2a2f1b5491 # 08:01 16- 82 Merge 'shawnguo/for-next' into devel-hourly-2014071701 git bisect good 73c47688a039158a6d395629d3ab32e606e13d1a # 08:27 300+ 26 Merge 'regulator/for-next' into devel-hourly-2014071701 git bisect bad b973fdf5e6e6fe84b51f79919e5dc8574ae859da # 08:38 1- 32 Merge 'luto/sync_rand_seed' into devel-hourly-2014071701 git bisect good 5778e65d5ca52bebbaa023e177d863e44f098e96 # 08:44 300+ 0 random,x86: Add arch_get_slow_rng_u64 git bisect bad d07c7f1ed61789e175fa975134855be32263be2c # 08:52 0- 1 x86,kaslr: Use MSR_KVM_GET_RNG_SEED for KASLR if available git bisect good c6f07a63601fbb36c09bf250b5538abb47b51e44 # 09:04 300+ 58 random: Seed pools from arch_get_slow_rng_u64 at startup # first bad commit: [d07c7f1ed61789e175fa975134855be32263be2c] x86,kaslr: Use MSR_KVM_GET_RNG_SEED for KASLR if available git bisect good c6f07a63601fbb36c09bf250b5538abb47b51e44 # 09:10 900+ 61 random: Seed pools from arch_get_slow_rng_u64 at startup git bisect bad 5e60c2af7a8bde5cfaee8ffd77cfc5b62db0a04e # 09:10 0- 10 0day head guard for 'devel-hourly-2014071701' git bisect good b6603fe574af289dbe9eb9fb4c540bca04f5a053 # 09:49 900+ 104 Merge tag 'for-linus-20140716' of git://git.infradead.org/linux-mtd git bisect good d4f4d1d45cd1b9aa60e61c2eab25a5d9a79a26f3 # 10:06 900+ 5 Add linux-next specific files for 20140716 This script may reproduce the error. ---------------------------------------------------------------------------- #!/bin/bash kernel=$1 kvm=( qemu-system-x86_64 -enable-kvm -cpu Haswell,+smep,+smap -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