Re: BUG: spinlock bad magic in synchronize_srcu

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    d1d2220c Add linux-next specific files for 20200924
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15bb8e09900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=254e028a642027c
dashboard link: https://syzkaller.appspot.com/bug?extid=05017ad275a64a3246f8
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=146e79ad900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+05017ad275a64a3246f8@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: spinlock bad magic on CPU#1, syz-executor.0/3687
 lock: 0xffff8880ae500040, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
CPU: 1 PID: 3687 Comm: syz-executor.0 Not tainted 5.9.0-rc6-next-20200924-syzkaller #0
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+0x198/0x1fb lib/dump_stack.c:118
 debug_spin_lock_before kernel/locking/spinlock_debug.c:83 [inline]
 do_raw_spin_lock+0x216/0x2b0 kernel/locking/spinlock_debug.c:112
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:117 [inline]
 _raw_spin_lock_irqsave+0x9c/0xd0 kernel/locking/spinlock.c:159
 srcu_might_be_idle kernel/rcu/srcutree.c:772 [inline]
 synchronize_srcu+0x4f/0x1c0 kernel/rcu/srcutree.c:999
 kvm_arch_destroy_vm+0x415/0x570 arch/x86/kvm/x86.c:10049
 kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:820 [inline]
 kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3914 [inline]
 kvm_dev_ioctl+0xf4b/0x13a0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3966
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e179
Code: 3d b2 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0b b2 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ff346cf4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000011180 RCX: 000000000045e179
RDX: 0000000000000000 RSI: 000000000000ae01 RDI: 0000000000000003
RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffefa62fbff R14: 00007ff346cf59c0 R15: 000000000118cf4c
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 3687 Comm: syz-executor.0 Not tainted 5.9.0-rc6-next-20200924-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:rcu_segcblist_enqueue+0x90/0xf0 kernel/rcu/rcu_segcblist.c:250
Code: 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 4e 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 20 48 89 ea 48 c1 ea 03 <80> 3c 02 00 75 21 48 89 75 00 48 89 73 20 48 83 c4 08 5b 5d c3 48
RSP: 0018:ffffc9000a297c08 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffff8880ae400080 RCX: ffffffff815bf5b0
RDX: 0000000000000000 RSI: ffffc9000a297cf0 RDI: ffff8880ae4000a0
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000003
R10: fffff52001452f73 R11: 6637303030302052 R12: ffffc9000a297cf0
R13: 0000000000000000 R14: ffff8880ae400080 R15: ffff8880ae400040
FS:  00007ff346cf5700(0000) GS:ffff8880ae400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3320e58db8 CR3: 000000007475a000 CR4: 00000000001526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __call_srcu+0x193/0xc50 kernel/rcu/srcutree.c:859
 __synchronize_srcu+0x128/0x220 kernel/rcu/srcutree.c:923
 kvm_arch_destroy_vm+0x415/0x570 arch/x86/kvm/x86.c:10049
 kvm_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:820 [inline]
 kvm_dev_ioctl_create_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:3914 [inline]
 kvm_dev_ioctl+0xf4b/0x13a0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3966
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e179
Code: 3d b2 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0b b2 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ff346cf4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000011180 RCX: 000000000045e179
RDX: 0000000000000000 RSI: 000000000000ae01 RDI: 0000000000000003
RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffefa62fbff R14: 00007ff346cf59c0 R15: 000000000118cf4c
Modules linked in:
---[ end trace 495d70ef5b659397 ]---
RIP: 0010:rcu_segcblist_enqueue+0x90/0xf0 kernel/rcu/rcu_segcblist.c:250
Code: 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 4e 48 b8 00 00 00 00 00 fc ff df 48 8b 6b 20 48 89 ea 48 c1 ea 03 <80> 3c 02 00 75 21 48 89 75 00 48 89 73 20 48 83 c4 08 5b 5d c3 48
RSP: 0018:ffffc9000a297c08 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffff8880ae400080 RCX: ffffffff815bf5b0
RDX: 0000000000000000 RSI: ffffc9000a297cf0 RDI: ffff8880ae4000a0
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000003
R10: fffff52001452f73 R11: 6637303030302052 R12: ffffc9000a297cf0
R13: 0000000000000000 R14: ffff8880ae400080 R15: ffff8880ae400040
FS:  00007ff346cf5700(0000) GS:ffff8880ae400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3320e58db8 CR3: 000000007475a000 CR4: 00000000001526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400