On Wed, Sep 7, 2016 at 12:31 AM, Paul E. McKenney <[email protected]> wrote: > On Tue, Sep 06, 2016 at 11:49:04AM -0400, Kees Cook wrote: >> On Sun, Sep 4, 2016 at 5:48 AM, Paul E. McKenney >> <[email protected]> wrote: >> > On Sun, Sep 04, 2016 at 08:35:40AM +0800, kernel test robot wrote: >> >> >> >> FYI, we noticed the following commit: >> >> >> >> https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git >> >> dev.2016.08.19a >> >> commit 8052ce2d9771ab5a818307f3abbaf33bba82a631 ("list: Split list_add() >> >> debug checking into separate function") >> >> >> >> in testcase: boot >> >> >> >> on test machine: qemu-system-i386 -enable-kvm -m 360M >> >> >> >> caused below changes: >> > >> > Hello, Kees, >> > >> > Looks like your change might have actually found a bug. ;-) >> > >> > How would you like to handle this? >> >> We should fix the bug! :) > > But of course... > > The question is whether I am considered to be fully responsible for > chasing down any bugs that arise. It is looking like I am, in which > case I must defer this patch to the 4.10 merge window. Things are a > bit crazy now due to prior overcommitments...
I'm going to double-check the code, but the changes I made shouldn't have changed any of the logical checks under CONFIG_DEBUG_LIST... just the manifestation of WARN vs BUG. So, since both this and the BPF RCU bug have appeared, something has changed... I will go digging... -Kees > > Yes, yes, they will be crazy then as well, but this would be higher > on the priority list. > > Thanx, Paul > >> >> +------------------------------------------------------------+------------+------------+ >> >> | | 0a33d912a3 >> >> | 8052ce2d97 | >> >> +------------------------------------------------------------+------------+------------+ >> >> | boot_successes | 0 >> >> | 0 | >> >> | boot_failures | 211 >> >> | 18 | >> >> | WARNING:at_lib/list_debug.c:#__list_del_entry | 211 >> >> | 18 | >> >> | calltrace:init | 209 >> >> | 18 | >> >> | WARNING:at_lib/list_debug.c:#__list_add | 209 >> >> | | >> >> | calltrace:i8042_init | 209 >> >> | 17 | >> >> | calltrace:SyS_reboot | 192 >> >> | 4 | >> >> | EIP_is_at__mutex_unlock_slowpath | 29 >> >> | | >> >> | Kernel_panic-not_syncing:softlockup:hung_tasks | 138 >> >> | | >> >> | BUG:workqueue_lockup-pool_cpus=#flags=#nice=#stuck_for#s | 56 >> >> | | >> >> | EIP_is_at_lock_release | 7 >> >> | | >> >> | EIP_is_at_lock_acquire | 28 >> >> | | >> >> | EIP_is_at_raw_spin_unlock_irq | 30 >> >> | | >> >> | EIP_is_at_mutex_lock_nested | 21 >> >> | | >> >> | EIP_is_at_lock_is_held | 10 >> >> | | >> >> | EIP_is_at_device_shutdown | 3 >> >> | | >> >> | EIP_is_at___might_sleep | 5 >> >> | | >> >> | EIP_is_at__list_del_entry | 4 >> >> | 1 | >> >> | EIP_is_at_get_device | 1 >> >> | | >> >> | BUG:unable_to_handle_kernel | 7 >> >> | 5 | >> >> | Oops | 7 >> >> | 5 | >> >> | calltrace:SyS_ipc | 4 >> >> | 4 | >> >> | Kernel_panic-not_syncing:Fatal_exception | 7 >> >> | 5 | >> >> | EIP_is_at_pm_runtime_barrier | 1 >> >> | | >> >> | EIP_is_at_lock_acquired | 1 >> >> | | >> >> | EIP_is_at__might_sleep | 1 >> >> | | >> >> | BUG:workqueue_lockup-pool_cpus=#-#flags=#nice=#stuck_for#s | 1 >> >> | | >> >> | WARNING:at_arch/x86/mm/dump_pagetables.c:#note_page | 26 >> >> | | >> >> | calltrace:mark_rodata_ro | 26 >> >> | | >> >> | WARNING:at_lib/list_debug.c:#__list_add_valid | 0 >> >> | 17 | >> >> | calltrace:serio_handle_event | 0 >> >> | 17 | >> >> | calltrace:userio_misc_init | 0 >> >> | 17 | >> >> | calltrace:mousedev_init | 0 >> >> | 17 | >> >> | calltrace:evdev_init | 0 >> >> | 17 | >> >> | calltrace:cmos_init | 0 >> >> | 17 | >> >> | calltrace:test_init | 0 >> >> | 17 | >> >> | calltrace:pca_isa_driver_init | 0 >> >> | 17 | >> >> | calltrace:vim2m_init | 0 >> >> | 17 | >> >> | calltrace:fm_drv_init | 0 >> >> | 17 | >> >> | calltrace:test_power_init | 0 >> >> | 17 | >> >> | calltrace:raid#_init | 0 >> >> | 17 | >> >> | calltrace:dm_init | 0 >> >> | 17 | >> >> | calltrace:vhci_init | 0 >> >> | 17 | >> >> | calltrace:dcdrbu_init | 0 >> >> | 17 | >> >> | calltrace:dcdbas_init | 0 >> >> | 17 | >> >> | calltrace:uhid_init | 0 >> >> | 17 | >> >> | calltrace:vhost_net_init | 0 >> >> | 17 | >> >> | calltrace:dummy_stm_init | 0 >> >> | 17 | >> >> | calltrace:stm_heartbeat_init | 0 >> >> | 17 | >> >> | calltrace:binder_init | 0 >> >> | 17 | >> >> | calltrace:teql_init | 0 >> >> | 17 | >> >> | calltrace:ipip_init | 0 >> >> | 17 | >> >> | calltrace:ipgre_init | 0 >> >> | 17 | >> >> | calltrace:sit_init | 0 >> >> | 17 | >> >> | calltrace:ip6_tunnel_init | 0 >> >> | 17 | >> >> | calltrace:ip6gre_init | 0 >> >> | 17 | >> >> | calltrace:irlan_init | 0 >> >> | 17 | >> >> | calltrace:pm_qos_power_init | 0 >> >> | 17 | >> >> | calltrace:ubi_init | 0 >> >> | 17 | >> >> | calltrace:SyS_setsockopt | 0 >> >> | 2 | >> >> | calltrace:SyS_socketcall | 0 >> >> | 2 | >> >> | WARNING:at_include/linux/kref.h:#kobject_get | 0 >> >> | 4 | >> >> | WARNING:at_kernel/locking/lockdep.c:#__lock_acquire | 0 >> >> | 4 | >> >> | BUG:kernel_hang_in_test_stage | 0 >> >> | 4 | >> >> | calltrace:fw_cfg_sysfs_init | 0 >> >> | 7 | >> >> +------------------------------------------------------------+------------+------------+ >> >> >> >> >> >> >> >> [ 152.680291] g_acm_ms usbip-vudc.0: failed to start g_acm_ms: -22 >> >> [ 152.689209] usbip-vudc: probe of usbip-vudc.0 failed with error -22 >> >> [ 152.698509] ------------[ cut here ]------------ >> >> [ 152.709786] WARNING: CPU: 0 PID: 1 at lib/list_debug.c:60 >> >> __list_del_entry+0x4d/0x71 >> >> [ 152.722785] list_del corruption. next->prev should be cc0230d4, but >> >> was 6b6b6b6b >> >> That's the poison value, so this is a remove-after-remove bug? >> >> >> [ 152.732828] CPU: 0 PID: 1 Comm: swapper/0 Not tainted >> >> 4.8.0-rc1-00033-g8052ce2 #1 >> >> [ 152.742576] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), >> >> BIOS Debian-1.8.2-1 04/01/2014 >> >> [ 152.754081] 00000000 00200246 c0033e78 c13c456b c0033ea4 c13e72ac >> >> c0033e90 c103fd02 >> >> [ 152.765720] 0000003c 6b6b6b6b cc0230d4 cc02300c c0033eac c103fd41 >> >> 00000009 00000000 >> >> [ 152.776864] c0033ea4 c1f7bc14 c0033ec0 c0033ecc c13e72ac c1f7bace >> >> 0000003c c1f7bc14 >> >> [ 152.788472] Call Trace: >> >> [ 152.791964] [<c13c456b>] dump_stack+0x75/0xa9 >> >> [ 152.797835] [<c13e72ac>] ? __list_del_entry+0x4d/0x71 >> >> [ 152.804221] [<c103fd02>] __warn+0xad/0xc4 >> >> [ 152.809694] [<c103fd41>] warn_slowpath_fmt+0x28/0x2d >> >> [ 152.816501] [<c13e72ac>] __list_del_entry+0x4d/0x71 >> >> [ 152.822946] [<c15027a8>] device_pm_remove+0x2b/0x5a >> >> [ 152.829560] [<c14f6317>] device_del+0x134/0x19a >> >> [ 152.835558] [<c14f5c38>] ? dev_set_name+0x14/0x16 >> >> [ 152.842135] [<c14f9d7c>] platform_device_del+0x16/0x5d >> >> [ 152.848909] [<c2207515>] init+0xe5/0x112 >> >> [ 152.854149] [<c2207430>] ? usbip_host_init+0xe5/0xe5 >> >> What device is this? Looks like it's being removed right at init time?? >> >> >> [ 152.860796] [<c21cec35>] do_one_initcall+0x7e/0x101 >> >> [ 152.867316] [<c10564b7>] ? parse_args+0x190/0x265 >> >> [ 152.873497] [<c21ced88>] ? kernel_init_freeable+0xd0/0x174 >> >> [ 152.880923] [<c21ceda4>] kernel_init_freeable+0xec/0x174 >> >> [ 152.887499] [<c1be421b>] kernel_init+0x8/0xd0 >> >> [ 152.893658] [<c1bec3ae>] ret_from_kernel_thread+0xe/0x30 >> >> [ 152.900759] [<c1be4213>] ? rest_init+0x111/0x111 >> >> [ 152.907334] ---[ end trace 2003739b08d25430 ]--- >> >> [ 152.920040] ------------[ cut here ]------------ >> >> -Kees >> >> >> -- >> Kees Cook >> Nexus Security >> > -- Kees Cook Nexus Security
