bisecting fixing commit since be9b6782a9eb128a45b4d4fce556f7053234773d
building syzkaller on de453f342be9edcca7de5a41e153ced8ad7f1a70
testing commit be9b6782a9eb128a45b4d4fce556f7053234773d with gcc (GCC) 8.1.0
kernel signature: f608d37d3e8e0f803ab3c1fef8d5040092dddcc5
run #0: crashed: WARNING: locking bug in do_ipv6_setsockopt
run #1: crashed: WARNING: locking bug in do_ipv6_setsockopt
run #2: crashed: WARNING: locking bug in do_ipv6_setsockopt
run #3: crashed: WARNING: locking bug in do_ipv6_setsockopt
run #4: crashed: WARNING: locking bug in do_ipv6_setsockopt
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
testing current HEAD 312017a460d5ea31d646e7148e400e13db799ddc
testing commit 312017a460d5ea31d646e7148e400e13db799ddc with gcc (GCC) 8.1.0
kernel signature: 1f870d8bb1e030c22b77473ed8602168686f7645
run #0: crashed: WARNING: locking bug in do_ipv6_setsockopt
run #1: crashed: WARNING: locking bug in do_ipv6_setsockopt
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
revisions tested: 2, total time: 37m39.794307048s (build: 17m16.748819503s, test: 19m51.781558222s)
the crash still happens on HEAD
commit msg: Linux 4.19.89
crash: WARNING: locking bug in do_ipv6_setsockopt
WARNING: CPU: 0 PID: 23844 at kernel/locking/lockdep.c:698 arch_local_save_flags arch/x86/include/asm/paravirt.h:784 [inline]
WARNING: CPU: 0 PID: 23844 at kernel/locking/lockdep.c:698 look_up_lock_class kernel/locking/lockdep.c:689 [inline]
WARNING: CPU: 0 PID: 23844 at kernel/locking/lockdep.c:698 register_lock_class+0xb95/0x2350 kernel/locking/lockdep.c:748
Kernel panic - not syncing: panic_on_warn set ...

kobject: 'loop3' (00000000b84b8a13): kobject_uevent_env
CPU: 0 PID: 23844 Comm: syz-executor.1 Not tainted 4.19.89-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+0x123/0x177 lib/dump_stack.c:118
 panic+0x1cd/0x375 kernel/panic.c:186
 __warn.cold.8+0x1b/0x3e kernel/panic.c:541
 report_bug+0x1a4/0x200 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x200/0x350 arch/x86/kernel/traps.c:296
kobject: 'loop3' (00000000b84b8a13): fill_kobj_path: path = '/devices/virtual/block/loop3'
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
kobject: 'loop5' (00000000dd673f5e): kobject_uevent_env
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1037
RIP: 0010:look_up_lock_class kernel/locking/lockdep.c:698 [inline]
RIP: 0010:register_lock_class+0xb95/0x2350 kernel/locking/lockdep.c:748
kobject: 'loop5' (00000000dd673f5e): fill_kobj_path: path = '/devices/virtual/block/loop5'
Code: 00 48 89 ca 4d 8b 7e c0 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 53 0f 00 00 4c 89 39 e9 f8 f7 ff ff 0f 0b <0f> 0b e9 da f6 ff ff 49 8d 46 01 4d 69 f6 50 01 00 00 48 89 05 c2
RSP: 0018:ffff8880a90f7590 EFLAGS: 00010083
RAX: 0000000000000004 RBX: ffffffff896095d0 RCX: ffff88808fbfa7e0
RDX: 1ffffffff13506d4 RSI: 0000000000000000 RDI: ffff88808fbfa7f8
RBP: ffff8880a90f7670 R08: 1ffff1101521eebd R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000003
R13: 0000000000000000 R14: ffffffff8765d3e0 R15: ffffffff87549200
 __lock_acquire+0x160/0x4980 kernel/locking/lockdep.c:3299
 lock_acquire+0x173/0x3d0 kernel/locking/lockdep.c:3903
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168
kobject: 'loop3' (00000000b84b8a13): kobject_uevent_env
 spin_lock_bh include/linux/spinlock.h:334 [inline]
 lock_sock_nested+0x3a/0x100 net/core/sock.c:2838
 lock_sock include/net/sock.h:1501 [inline]
 do_ipv6_setsockopt.isra.8+0x2da/0x33d0 net/ipv6/ipv6_sockglue.c:167
kobject: 'loop3' (00000000b84b8a13): fill_kobj_path: path = '/devices/virtual/block/loop3'
kobject: 'loop2' (0000000046f2b398): kobject_uevent_env
kobject: 'loop2' (0000000046f2b398): fill_kobj_path: path = '/devices/virtual/block/loop2'
kobject: 'loop0' (000000002a324fd3): kobject_uevent_env
kobject: 'loop0' (000000002a324fd3): fill_kobj_path: path = '/devices/virtual/block/loop0'
 ipv6_setsockopt+0x6e/0xf0 net/ipv6/ipv6_sockglue.c:933
 udpv6_setsockopt+0x16/0x30 net/ipv6/udp.c:1498
 sock_common_setsockopt+0x73/0xf0 net/core/sock.c:3046
 __sys_setsockopt+0x13e/0x210 net/socket.c:1901
 __do_sys_setsockopt net/socket.c:1912 [inline]
 __se_sys_setsockopt net/socket.c:1909 [inline]
 __x64_sys_setsockopt+0xb9/0x150 net/socket.c:1909
 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459829
Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc49cf76c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000459829
RDX: 0000000000000023 RSI: 0000000000000029 RDI: 0000000000000006
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc49cf776d4
R13: 00000000004ced30 R14: 00000000004dd678 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..