Hi Andy, Here is another WARNING message for the same 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 +-------------------------------------------------------------------------+------------+------------+ | | c6f07a6360 | d07c7f1ed6 | +-------------------------------------------------------------------------+------------+------------+ | boot_successes | 1000 | 636 | | boot_failures | 0 | 84 | | WARNING:CPU:PID:at_arch/x86/kernel/cpu/common.c:warn_pre_alternatives() | 0 | 84 | | BUG:unable_to_handle_kernel_NULL_pointer_dereference | 0 | 84 | | Oops | 0 | 84 | | RIP:__free_pages_bootmem | 0 | 84 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 84 | | backtrace:free_all_bootmem | 0 | 84 | | backtrace:mem_init | 0 | 84 | +-------------------------------------------------------------------------+------------+------------+ [ 0.000000] PID hash table entries: 2048 (order: 2, 16384 bytes) [ 0.000000] xsave: enabled xstate_bv 0x7, cntxt size 0x0 [ 0.000000] ------------[ cut here ]------------ [ 0.000000] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/cpu/common.c:1422 warn_pre_alternatives+0x1e/0x20() [ 0.000000] You're using static_cpu_has before alternatives have run! [ 0.000000] Modules linked in: [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 3.16.0-rc5-00004-gd07c7f1 #4 [ 0.000000] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 0.000000] 0000000000000000 ffffffff81803c18 ffffffff813a7bd2 ffffffff81803c60 [ 0.000000] ffffffff81803c50 ffffffff810a5485 ffffffff810102f9 ffffffff81803e08 [ 0.000000] 0000000000000002 000000000000077c 0000000000000000 ffffffff81803cb0 [ 0.000000] Call Trace: [ 0.000000] [] dump_stack+0x4d/0x66 [ 0.000000] [] warn_slowpath_common+0x7f/0x98 [ 0.000000] [] ? warn_pre_alternatives+0x1e/0x20 [ 0.000000] [] warn_slowpath_fmt+0x4c/0x4e [ 0.000000] [] ? restore_args+0x30/0x30 [ 0.000000] [] warn_pre_alternatives+0x1e/0x20 [ 0.000000] [] __do_page_fault+0x1bd/0x7ca [ 0.000000] [] ? console_unlock+0x377/0x3c1 [ 0.000000] [] ? trace_hardirqs_off+0xd/0xf [ 0.000000] [] ? _raw_spin_unlock_irqrestore+0x40/0x5e [ 0.000000] [] ? __next_mem_range_rev+0x205/0x232 [ 0.000000] [] ? trace_hardirqs_off_caller+0xe7/0x128 [ 0.000000] [] ? trace_hardirqs_off_thunk+0x3a/0x3c [ 0.000000] [] do_page_fault+0x22/0x27 [ 0.000000] [] page_fault+0x28/0x30 [ 0.000000] [] ? __free_pages_bootmem+0x2d/0xf9 [ 0.000000] [] __free_memory_core+0xa7/0xbe [ 0.000000] [] free_all_bootmem+0x51/0xd2 [ 0.000000] [] mem_init+0x5c/0x8d [ 0.000000] [] start_kernel+0x1f7/0x53d [ 0.000000] [] ? set_init_arg+0x55/0x55 [ 0.000000] [] ? early_idt_handlers+0x120/0x120 [ 0.000000] [] x86_64_start_reservations+0x2a/0x2c [ 0.000000] [] x86_64_start_kernel+0x140/0x14d [ 0.000000] ---[ end trace e4962b91bd705c64 ]--- [ 0.000000] BUG: unable to handle kernel NULL pointer dereference at 000000000000077c git bisect start 5e60c2af7a8bde5cfaee8ffd77cfc5b62db0a04e 1795cd9b3a91d4b5473c97f491d63892442212ab -- git bisect good bc1f2f93f68bccd988af7e6f73384860ac241b78 # 09:04 720+ 0 Merge 'socfpga-nex/nios2-upstream' into devel-hourly-2014071701 git bisect bad 0d7e1ca40ef16fce5297579121717fc793761b38 # 09:04 0- 16 Merge 'dynticks/nohz/sysidle' into devel-hourly-2014071701 git bisect good 33c13bf2487a42efa1ac9bcce5623ab74a375c93 # 09:08 720+ 0 Merge 'ubifs/linux-next' into devel-hourly-2014071701 git bisect good 1032f73a32951d7f14ed7fdadedb0fef3c6d0f49 # 09:12 720+ 0 Merge 'spi/for-next' into devel-hourly-2014071701 git bisect bad 1f2859f0786338fe4c2a18ea518a5b2a2f1b5491 # 09:12 0- 126 Merge 'shawnguo/for-next' into devel-hourly-2014071701 git bisect good 73c47688a039158a6d395629d3ab32e606e13d1a # 09:24 720+ 0 Merge 'regulator/for-next' into devel-hourly-2014071701 git bisect bad b973fdf5e6e6fe84b51f79919e5dc8574ae859da # 09:27 27- 18 Merge 'luto/sync_rand_seed' into devel-hourly-2014071701 git bisect good 5778e65d5ca52bebbaa023e177d863e44f098e96 # 09:36 720+ 0 random,x86: Add arch_get_slow_rng_u64 git bisect bad d07c7f1ed61789e175fa975134855be32263be2c # 09:39 0- 9 x86,kaslr: Use MSR_KVM_GET_RNG_SEED for KASLR if available git bisect good c6f07a63601fbb36c09bf250b5538abb47b51e44 # 09:44 720+ 0 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 # 09:46 1000+ 0 random: Seed pools from arch_get_slow_rng_u64 at startup git bisect bad 5e60c2af7a8bde5cfaee8ffd77cfc5b62db0a04e # 09:48 0- 3 0day head guard for 'devel-hourly-2014071701' git bisect good b6603fe574af289dbe9eb9fb4c540bca04f5a053 # 10:02 1000+ 0 Merge tag 'for-linus-20140716' of git://git.infradead.org/linux-mtd git bisect good d4f4d1d45cd1b9aa60e61c2eab25a5d9a79a26f3 # 12:20 1000+ 0 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 $kernel -m 320 -smp 1 -net nic,vlan=1,model=e1000 -net user,vlan=1 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -serial stdio -display none -monitor null ) append=( hung_task_panic=1 earlyprintk=ttyS0,115200 debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 panic=10 softlockup_panic=1 nmi_watchdog=panic prompt_ramdisk=0 console=ttyS0,115200 console=tty0 vga=normal root=/dev/ram0 rw drbd.minor_count=8 ) "${kvm[@]}" --append "${append[*]}" ---------------------------------------------------------------------------- Thanks, Fengguang _______________________________________________ LKP mailing list LKP(a)linux.intel.com