Messages in this thread | | | Subject | Re: WARNING in __debug_object_init (3) | From | Eric Dumazet <> | Date | Sun, 28 Oct 2018 10:44:00 -0700 |
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On 10/28/2018 08:13 AM, Dmitry Vyukov wrote: > On Sun, Oct 28, 2018 at 3:18 AM, syzbot > <syzbot+6e682caa546b7c96c859@syzkaller.appspotmail.com> wrote: >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit: 8c60c36d0b8c Add linux-next specific files for 20181019 >> git tree: linux-next >> console output: https://syzkaller.appspot.com/x/log.txt?x=100feec5400000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=8b6d7c4c81535e89 >> dashboard link: https://syzkaller.appspot.com/bug?extid=6e682caa546b7c96c859 >> compiler: gcc (GCC) 8.0.1 20180413 (experimental) >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13579abd400000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13654f6b400000 >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+6e682caa546b7c96c859@syzkaller.appspotmail.com > > +Eric knows what's wrong here. Something about "bpf: add tests for > direct packet access from CGROUP_SKB" commit. Was is amended to fix a > bug? >
I know little.
It seems that this linux-next tree contains a (buggy) pre-version of this commit :
commit 2cb494a36c98279c5c6ce8e99cf9776f15449ade Author: Song Liu <songliubraving@fb.com> Date: Fri Oct 19 09:57:58 2018 -0700
bpf: add tests for direct packet access from CGROUP_SKB
Tests are added to make sure CGROUP_SKB cannot access: tc_classid, data_meta, flow_keys
and can read and write: mark, prority, and cb[0-4]
and can read other fields.
To make selftest with skb->sk work, a dummy sk is added in bpf_prog_test_run_skb().
Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Maybe bpf maintainers chose to pre-submit a buggy patch and rebased their tree.
The buggy patch in linux-next was :
commit 75079847e9d05d4cc1b7e09b29e22cbc8318a6b7 Author: Song Liu <songliubraving@fb.com> Date: Thu Oct 18 09:06:49 2018 -0700
bpf: add tests for direct packet access from CGROUP_SKB
Tests are added to make sure CGROUP_SKB cannot access: tc_classid, data_meta, flow_keys
and can read and write: mark, prority, and cb[0-4]
and can read other fields.
To make selftest with skb->sk work, a dummy sk is added in bpf_prog_test_run_skb().
Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
> >> ODEBUG: object 0000000015e9012c is on stack 00000000115bcb67, but NOT >> annotated. >> WARNING: CPU: 0 PID: 5594 at lib/debugobjects.c:369 debug_object_is_on_stack >> lib/debugobjects.c:363 [inline] >> WARNING: CPU: 0 PID: 5594 at lib/debugobjects.c:369 >> __debug_object_init.cold.14+0x51/0xdf lib/debugobjects.c:395 >> Kernel panic - not syncing: panic_on_warn set ... >> CPU: 0 PID: 5594 Comm: syz-executor740 Not tainted 4.19.0-rc8-next-20181019+ >> #98 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> Google 01/01/2011 >> Call Trace: >> __dump_stack lib/dump_stack.c:77 [inline] >> dump_stack+0x244/0x39d lib/dump_stack.c:113 >> panic+0x2ad/0x55c kernel/panic.c:188 >> __warn.cold.8+0x20/0x45 kernel/panic.c:540 >> report_bug+0x254/0x2d0 lib/bug.c:186 >> fixup_bug arch/x86/kernel/traps.c:178 [inline] >> do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 >> do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290 >> invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969 >> RIP: 0010:debug_object_is_on_stack lib/debugobjects.c:363 [inline] >> RIP: 0010:__debug_object_init.cold.14+0x51/0xdf lib/debugobjects.c:395 >> Code: ea 03 80 3c 02 00 75 7c 49 8b 54 24 18 48 89 de 48 c7 c7 c0 f1 40 88 >> 4c 89 85 d0 fd ff ff e8 09 8c d1 fd 4c 8b 85 d0 fd ff ff <0f> 0b e9 09 d6 ff >> ff 41 83 c4 01 b8 ff ff 37 00 44 89 25 b7 4e 66 >> RSP: 0018:ffff8801bb387308 EFLAGS: 00010086 >> RAX: 0000000000000050 RBX: ffff8801bb387af8 RCX: 0000000000000000 >> RDX: 0000000000000000 RSI: ffffffff816585a5 RDI: 0000000000000005 >> RBP: ffff8801bb387560 R08: ffff8801cb208a20 R09: ffffed003b5c5008 >> R10: ffffed003b5c5008 R11: ffff8801dae28047 R12: ffff8801d82ea300 >> R13: 0000000000069700 R14: ffff8801d82ea300 R15: ffff8801cb208a10 >> debug_object_init+0x16/0x20 lib/debugobjects.c:432 >> debug_timer_init kernel/time/timer.c:704 [inline] >> debug_init kernel/time/timer.c:757 [inline] >> init_timer_key+0xa9/0x480 kernel/time/timer.c:806 >> sock_init_data+0xe1/0xdc0 net/core/sock.c:2696 >> bpf_prog_test_run_skb+0x255/0xc40 net/bpf/test_run.c:144 >> bpf_prog_test_run+0x130/0x1a0 kernel/bpf/syscall.c:1790 >> __do_sys_bpf kernel/bpf/syscall.c:2427 [inline] >> __se_sys_bpf kernel/bpf/syscall.c:2371 [inline] >> __x64_sys_bpf+0x3d8/0x510 kernel/bpf/syscall.c:2371 >> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> RIP: 0033:0x440259 >> Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 >> 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff >> 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 >> RSP: 002b:00007ffc212cf818 EFLAGS: 00000213 ORIG_RAX: 0000000000000141 >> RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440259 >> RDX: 0000000000000028 RSI: 0000000020000080 RDI: 000000000000000a >> RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 >> R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401ae0 >> R13: 0000000000401b70 R14: 0000000000000000 R15: 0000000000000000 >> >> ====================================================== >> WARNING: possible circular locking dependency detected >> 4.19.0-rc8-next-20181019+ #98 Not tainted >> ------------------------------------------------------ >> syz-executor740/5594 is trying to acquire lock: >> 00000000688fcc6b ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70 >> kernel/locking/semaphore.c:136 >> >> but task is already holding lock: >> 00000000505ead1b (&obj_hash[i].lock){-.-.}, at: >> __debug_object_init+0x127/0x1290 lib/debugobjects.c:384 >> >> which lock already depends on the new lock. >> >> >> the existing dependency chain (in reverse order) is: >> >> -> #3 (&obj_hash[i].lock){-.-.}: >> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] >> _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152 >> __debug_object_init+0x127/0x1290 lib/debugobjects.c:384 >> debug_object_init+0x16/0x20 lib/debugobjects.c:432 >> debug_hrtimer_init kernel/time/hrtimer.c:410 [inline] >> debug_init kernel/time/hrtimer.c:458 [inline] >> hrtimer_init+0x97/0x490 kernel/time/hrtimer.c:1308 >> init_dl_task_timer+0x1b/0x50 kernel/sched/deadline.c:1057 >> __sched_fork+0x2ae/0x590 kernel/sched/core.c:2166 >> init_idle+0x75/0x740 kernel/sched/core.c:5382 >> sched_init+0xb33/0xc02 kernel/sched/core.c:6065 >> start_kernel+0x4be/0xa2b init/main.c:608 >> x86_64_start_reservations+0x2e/0x30 arch/x86/kernel/head64.c:472 >> x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:451 >> secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 >> >> -> #2 (&rq->lock){-.-.}: >> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] >> _raw_spin_lock+0x2d/0x40 kernel/locking/spinlock.c:144 >> rq_lock kernel/sched/sched.h:1127 [inline] >> task_fork_fair+0xb0/0x6d0 kernel/sched/fair.c:9768 >> sched_fork+0x443/0xba0 kernel/sched/core.c:2359 >> copy_process+0x2585/0x8770 kernel/fork.c:1887 >> _do_fork+0x1cb/0x11c0 kernel/fork.c:2216 >> kernel_thread+0x34/0x40 kernel/fork.c:2275 >> rest_init+0x28/0x372 init/main.c:409 >> arch_call_rest_init+0xe/0x1b >> start_kernel+0x9f0/0xa2b init/main.c:745 >> x86_64_start_reservations+0x2e/0x30 arch/x86/kernel/head64.c:472 >> x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:451 >> secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 >> >> -> #1 (&p->pi_lock){-.-.}: >> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] >> _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152 >> try_to_wake_up+0xd2/0x12e0 kernel/sched/core.c:1965 >> wake_up_process+0x10/0x20 kernel/sched/core.c:2129 >> __up.isra.1+0x1c0/0x2a0 kernel/locking/semaphore.c:262 >> up+0x13c/0x1c0 kernel/locking/semaphore.c:187 >> __up_console_sem+0xbe/0x1b0 kernel/printk/printk.c:236 >> console_unlock+0x80c/0x1190 kernel/printk/printk.c:2432 >> vprintk_emit+0x391/0x990 kernel/printk/printk.c:1922 >> vprintk_default+0x28/0x30 kernel/printk/printk.c:1964 >> vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398 >> printk+0xa7/0xcf kernel/printk/printk.c:1997 >> check_stack_usage kernel/exit.c:755 [inline] >> do_exit.cold.18+0x57/0x16f kernel/exit.c:916 >> do_group_exit+0x177/0x440 kernel/exit.c:970 >> __do_sys_exit_group kernel/exit.c:981 [inline] >> __se_sys_exit_group kernel/exit.c:979 [inline] >> __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:979 >> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> >> -> #0 ((console_sem).lock){-.-.}: >> lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 >> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] >> _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152 >> down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 >> __down_trylock_console_sem+0xae/0x1f0 kernel/printk/printk.c:219 >> console_trylock+0x15/0xa0 kernel/printk/printk.c:2247 >> console_trylock_spinning kernel/printk/printk.c:1653 [inline] >> vprintk_emit+0x372/0x990 kernel/printk/printk.c:1921 >> vprintk_default+0x28/0x30 kernel/printk/printk.c:1964 >> vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398 >> printk+0xa7/0xcf kernel/printk/printk.c:1997 >> debug_object_is_on_stack lib/debugobjects.c:363 [inline] >> __debug_object_init.cold.14+0x4a/0xdf lib/debugobjects.c:395 >> debug_object_init+0x16/0x20 lib/debugobjects.c:432 >> debug_timer_init kernel/time/timer.c:704 [inline] >> debug_init kernel/time/timer.c:757 [inline] >> init_timer_key+0xa9/0x480 kernel/time/timer.c:806 >> sock_init_data+0xe1/0xdc0 net/core/sock.c:2696 >> bpf_prog_test_run_skb+0x255/0xc40 net/bpf/test_run.c:144 >> bpf_prog_test_run+0x130/0x1a0 kernel/bpf/syscall.c:1790 >> __do_sys_bpf kernel/bpf/syscall.c:2427 [inline] >> __se_sys_bpf kernel/bpf/syscall.c:2371 [inline] >> __x64_sys_bpf+0x3d8/0x510 kernel/bpf/syscall.c:2371 >> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> >> other info that might help us debug this: >> >> Chain exists of: >> (console_sem).lock --> &rq->lock --> &obj_hash[i].lock >> >> Possible unsafe locking scenario: >> >> CPU0 CPU1 >> ---- ---- >> lock(&obj_hash[i].lock); >> lock(&rq->lock); >> lock(&obj_hash[i].lock); >> lock((console_sem).lock); >> >> *** DEADLOCK *** >> >> 1 lock held by syz-executor740/5594: >> #0: 00000000505ead1b (&obj_hash[i].lock){-.-.}, at: >> __debug_object_init+0x127/0x1290 lib/debugobjects.c:384 >> >> stack backtrace: >> CPU: 0 PID: 5594 Comm: syz-executor740 Not tainted 4.19.0-rc8-next-20181019+ >> #98 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> Google 01/01/2011 >> Call Trace: >> __dump_stack lib/dump_stack.c:77 [inline] >> dump_stack+0x244/0x39d lib/dump_stack.c:113 >> print_circular_bug.isra.35.cold.54+0x1bd/0x27d >> kernel/locking/lockdep.c:1221 >> check_prev_add kernel/locking/lockdep.c:1863 [inline] >> check_prevs_add kernel/locking/lockdep.c:1976 [inline] >> validate_chain kernel/locking/lockdep.c:2347 [inline] >> __lock_acquire+0x3399/0x4c20 kernel/locking/lockdep.c:3341 >> lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 >> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] >> _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152 >> down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 >> __down_trylock_console_sem+0xae/0x1f0 kernel/printk/printk.c:219 >> console_trylock+0x15/0xa0 kernel/printk/printk.c:2247 >> console_trylock_spinning kernel/printk/printk.c:1653 [inline] >> vprintk_emit+0x372/0x990 kernel/printk/printk.c:1921 >> vprintk_default+0x28/0x30 kernel/printk/printk.c:1964 >> vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398 >> printk+0xa7/0xcf kernel/printk/printk.c:1997 >> debug_object_is_on_stack lib/debugobjects.c:363 [inline] >> __debug_object_init.cold.14+0x4a/0xdf lib/debugobjects.c:395 >> debug_object_init+0x16/0x20 lib/debugobjects.c:432 >> debug_timer_init kernel/time/timer.c:704 [inline] >> debug_init kernel/time/timer.c:757 [inline] >> init_timer_key+0xa9/0x480 kernel/time/timer.c:806 >> sock_init_data+0xe1/0xdc0 net/core/sock.c:2696 >> bpf_prog_test_run_skb+0x255/0xc40 net/bpf/test_run.c:144 >> bpf_prog_test_run+0x130/0x1a0 kernel/bpf/syscall.c:1790 >> __do_sys_bpf kernel/bpf/syscall.c:2427 [inline] >> __se_sys_bpf kernel/bpf/syscall.c:2371 [inline] >> __x64_sys_bpf+0x3d8/0x510 kernel/bpf/syscall.c:2371 >> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> RIP: 0033:0x440259 >> Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 >> 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff >> 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 >> RSP: 002b:00007ffc212cf818 EFLAGS: 00000213 ORIG_RAX: 0000000000000141 >> RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440259 >> RDX: 0000000000000028 RSI: 0000000020000080 RDI: 000000000000000a >> RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 >> R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401ae0 >> R13: 0000000000401b70 R14: 0000000000000000 R15: 0000000000000000 >> Kernel Offset: disabled >> Rebooting in 86400 seconds.. >> >> >> --- >> This bug is generated by a bot. It may contain errors. >> See https://goo.gl/tpsmEJ for more information about syzbot. >> syzbot engineers can be reached at syzkaller@googlegroups.com. >> >> syzbot will keep track of this bug report. See: >> https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with >> syzbot. >> syzbot can test patches for this bug, for details see: >> https://goo.gl/tpsmEJ#testing-patches >> >> -- >> You received this message because you are subscribed to the Google Groups >> "syzkaller-bugs" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to syzkaller-bugs+unsubscribe@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/syzkaller-bugs/0000000000008db3210579416691%40google.com. >> For more options, visit https://groups.google.com/d/optout.
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