INFO: task kworker/0:9:9242 blocked for more than 143 seconds. Not tainted 5.15.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:9 state:D stack:26776 pid: 9242 ppid: 2 flags:0x00004000 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729 addrconf_dad_work+0xa3/0x1340 net/ipv6/addrconf.c:4047 process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 INFO: task kworker/1:0:24680 blocked for more than 143 seconds. Not tainted 5.15.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:0 state:D stack:25936 pid:24680 ppid: 2 flags:0x00004000 Workqueue: events switchdev_deferred_process_work Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729 switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74 process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 INFO: task kworker/0:0:31055 blocked for more than 143 seconds. Not tainted 5.15.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:0 state:D stack:27056 pid:31055 ppid: 2 flags:0x00004000 Workqueue: events linkwatch_event Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729 linkwatch_event+0xb/0x60 net/core/link_watch.c:251 process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 INFO: task kworker/1:10:9581 blocked for more than 143 seconds. Not tainted 5.15.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:10 state:D stack:26672 pid: 9581 ppid: 2 flags:0x00004000 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729 addrconf_dad_work+0xa3/0x1340 net/ipv6/addrconf.c:4047 process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 INFO: task syz-executor.1:28171 blocked for more than 144 seconds. Not tainted 5.15.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.1 state:D stack:28304 pid:28171 ppid: 27644 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729 dev_ioctl+0x279/0xee0 net/core/dev_ioctl.c:611 sock_ioctl+0x537/0x640 net/socket.c:1162 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fdc94057a39 RSP: 002b:00007fdc915cd188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fdc9415af60 RCX: 00007fdc94057a39 RDX: 0000000020000100 RSI: 00000000000089f3 RDI: 0000000000000003 RBP: 00007fdc940b1c5f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd4bcad48f R14: 00007fdc915cd300 R15: 0000000000022000 INFO: task syz-executor.5:28187 blocked for more than 144 seconds. Not tainted 5.15.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.5 state:D stack:29168 pid:28187 ppid: 8020 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb44/0x5960 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729 dev_ioctl+0x279/0xee0 net/core/dev_ioctl.c:611 sock_ioctl+0x537/0x640 net/socket.c:1162 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f2e76a1ea39 RSP: 002b:00007f2e73f94188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f2e76b21f60 RCX: 00007f2e76a1ea39 RDX: 0000000020000100 RSI: 00000000000089f3 RDI: 0000000000000003 RBP: 00007f2e76a78c5f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffc7625d5f R14: 00007f2e73f94300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/26: #0: ffffffff8b981ee0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446 1 lock held by in:imklog/6237: #0: ffff88801d8514f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 3 locks held by kworker/0:9/9242: #0: ffff8881481d8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881481d8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff8881481d8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline] #0: ffff8881481d8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline] #0: ffff8881481d8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline] #0: ffff8881481d8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x8a3/0x16b0 kernel/workqueue.c:2268 #1: ffffc90004127db0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8d7/0x16b0 kernel/workqueue.c:2272 #2: ffffffff8d0e8ea8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xa3/0x1340 net/ipv6/addrconf.c:4047 3 locks held by kworker/1:0/24680: #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline] #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline] #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline] #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x8a3/0x16b0 kernel/workqueue.c:2268 #1: ffffc90004cafdb0 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x8d7/0x16b0 kernel/workqueue.c:2272 #2: ffffffff8d0e8ea8 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:74 3 locks held by kworker/0:0/31055: #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline] #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline] #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline] #0: ffff888010c64d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x8a3/0x16b0 kernel/workqueue.c:2268 #1: ffffc900044afdb0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x8d7/0x16b0 kernel/workqueue.c:2272 #2: ffffffff8d0e8ea8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xb/0x60 net/core/link_watch.c:251 4 locks held by kworker/u4:8/8072: #0: ffff888015d93138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888015d93138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff888015d93138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline] #0: ffff888015d93138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline] #0: ffff888015d93138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline] #0: ffff888015d93138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x8a3/0x16b0 kernel/workqueue.c:2268 #1: ffffc90004c9fdb0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x8d7/0x16b0 kernel/workqueue.c:2272 #2: ffffffff8d0d5750 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xb00 net/core/net_namespace.c:555 #3: ffffffff8d0e8ea8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock_unregistering net/core/dev.c:11536 [inline] #3: ffffffff8d0e8ea8 (rtnl_mutex){+.+.}-{3:3}, at: default_device_exit_batch+0xe8/0x3c0 net/core/dev.c:11574 3 locks held by kworker/1:10/9581: #0: ffff8881481d8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881481d8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff8881481d8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline] #0: ffff8881481d8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline] #0: ffff8881481d8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline] #0: ffff8881481d8d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x8a3/0x16b0 kernel/workqueue.c:2268 #1: ffffc90004c8fdb0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8d7/0x16b0 kernel/workqueue.c:2272 #2: ffffffff8d0e8ea8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xa3/0x1340 net/ipv6/addrconf.c:4047 3 locks held by kworker/1:11/9583: #0: ffff888010c65d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888010c65d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff888010c65d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1198 [inline] #0: ffff888010c65d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:634 [inline] #0: ffff888010c65d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:661 [inline] #0: ffff888010c65d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x8a3/0x16b0 kernel/workqueue.c:2268 #1: ffffc900044ffdb0 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x8d7/0x16b0 kernel/workqueue.c:2272 #2: ffffffff8d0e8ea8 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x83/0xe10 net/wireless/reg.c:2423 1 lock held by syz-executor.1/28171: #0: ffffffff8d0e8ea8 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x279/0xee0 net/core/dev_ioctl.c:611 1 lock held by syz-executor.5/28187: #0: ffffffff8d0e8ea8 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x279/0xee0 net/core/dev_ioctl.c:611 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 26 Comm: khungtaskd Not tainted 5.15.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline] watchdog+0xc1d/0xf50 kernel/hung_task.c:295 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6238 Comm: rs:main Q:Reg Not tainted 5.15.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__lock_acquire+0x245/0x54a0 kernel/locking/lockdep.c:4949 Code: 28 0f b7 4c 24 10 49 8d 44 24 20 48 89 c2 48 89 44 24 38 66 81 e1 ff 1f 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 14 02 <84> d2 74 09 80 fa 03 0f 8e 33 13 00 00 41 0f b7 44 24 20 49 8d 7c RSP: 0018:ffffc9000c1ff520 EFLAGS: 00000806 RAX: dffffc0000000000 RBX: ffff88807e5a6b00 RCX: 000000000000057f RDX: 0000000000000000 RSI: 00000000000004d1 RDI: ffff88807d754390 RBP: 0000000000000000 R08: 1ffff1100faea872 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88807d754398 R13: ffff88807d753900 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f8663504700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb487860000 CR3: 000000006f030000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] ext4_do_update_inode fs/ext4/inode.c:4984 [inline] ext4_mark_iloc_dirty+0x230/0x3b20 fs/ext4/inode.c:5683 __ext4_mark_inode_dirty+0x222/0x8d0 fs/ext4/inode.c:5879 ext4_dirty_inode+0xd4/0x110 fs/ext4/inode.c:5908 __mark_inode_dirty+0x45b/0xfe0 fs/fs-writeback.c:2398 mark_inode_dirty include/linux/fs.h:2452 [inline] generic_write_end+0x31b/0x500 fs/buffer.c:2202 ext4_da_write_end+0x1c2/0x990 fs/ext4/inode.c:3062 generic_perform_write+0x2c3/0x510 mm/filemap.c:3781 ext4_buffered_write_iter+0x244/0x500 fs/ext4/file.c:269 ext4_file_write_iter+0x423/0x14e0 fs/ext4/file.c:680 call_write_iter include/linux/fs.h:2163 [inline] new_sync_write+0x429/0x660 fs/read_write.c:507 vfs_write+0x7cf/0xae0 fs/read_write.c:594 ksys_write+0x12d/0x250 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f8665f481cd Code: c2 20 00 00 75 10 b8 01 00 00 00 0f 05 48 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ae fc ff ff 48 89 04 24 b8 01 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 f7 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007f8663503590 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f8658029d80 RCX: 00007f8665f481cd RDX: 00000000000004be RSI: 00007f8658029d80 RDI: 000000000000000a RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 00007f8658029b00 R13: 00007f86635035b0 R14: 000055c02708c7c0 R15: 00000000000004be ---------------- Code disassembly (best guess): 0: 28 0f sub %cl,(%rdi) 2: b7 4c mov $0x4c,%bh 4: 24 10 and $0x10,%al 6: 49 8d 44 24 20 lea 0x20(%r12),%rax b: 48 89 c2 mov %rax,%rdx e: 48 89 44 24 38 mov %rax,0x38(%rsp) 13: 66 81 e1 ff 1f and $0x1fff,%cx 18: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1f: fc ff df 22: 48 c1 ea 03 shr $0x3,%rdx 26: 0f b6 14 02 movzbl (%rdx,%rax,1),%edx * 2a: 84 d2 test %dl,%dl <-- trapping instruction 2c: 74 09 je 0x37 2e: 80 fa 03 cmp $0x3,%dl 31: 0f 8e 33 13 00 00 jle 0x136a 37: 41 0f b7 44 24 20 movzwl 0x20(%r12),%eax 3d: 49 rex.WB 3e: 8d .byte 0x8d 3f: 7c .byte 0x7c