------------[ cut here ]------------ ====================================================== WARNING: possible circular locking dependency detected 5.15.172-syzkaller #0 Not tainted ------------------------------------------------------ udevd/3544 is trying to acquire lock: ffffffff8c7fc4b8 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:138 but task is already holding lock: ffff8880b9128098 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:946 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&base->lock){-.-.}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 lock_timer_base+0x120/0x260 kernel/time/timer.c:946 __mod_timer+0x1d6/0xeb0 kernel/time/timer.c:1019 queue_delayed_work_on+0x156/0x250 kernel/workqueue.c:1715 psi_enqueue kernel/sched/stats.h:104 [inline] enqueue_task+0x2fe/0x3a0 kernel/sched/core.c:1970 activate_task kernel/sched/core.c:2002 [inline] wake_up_new_task+0x515/0xb60 kernel/sched/core.c:4519 kernel_clone+0x44e/0x960 kernel/fork.c:2627 kernel_thread+0x168/0x1e0 kernel/fork.c:2655 rest_init+0x21/0x330 init/main.c:706 start_kernel+0x48c/0x540 init/main.c:1140 secondary_startup_64_no_verify+0xb1/0xbb -> #2 (&rq->__lock){-.-.}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 _raw_spin_lock_nested+0x2d/0x40 kernel/locking/spinlock.c:368 raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475 raw_spin_rq_lock kernel/sched/sched.h:1326 [inline] rq_lock kernel/sched/sched.h:1621 [inline] task_fork_fair+0x5d/0x350 kernel/sched/fair.c:11484 sched_cgroup_fork+0x2d3/0x330 kernel/sched/core.c:4463 copy_process+0x224a/0x3ef0 kernel/fork.c:2319 kernel_clone+0x210/0x960 kernel/fork.c:2603 kernel_thread+0x168/0x1e0 kernel/fork.c:2655 rest_init+0x21/0x330 init/main.c:706 start_kernel+0x48c/0x540 init/main.c:1140 secondary_startup_64_no_verify+0xb1/0xbb -> #1 (&p->pi_lock){-.-.}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 try_to_wake_up+0xae/0x1300 kernel/sched/core.c:4027 up+0x6e/0x90 kernel/locking/semaphore.c:190 __up_console_sem+0x11a/0x1e0 kernel/printk/printk.c:256 console_unlock+0x1145/0x12b0 kernel/printk/printk.c:2760 vprintk_emit+0xbf/0x150 kernel/printk/printk.c:2274 _printk+0xd1/0x120 kernel/printk/printk.c:2299 warn_mandlock fs/namespace.c:1727 [inline] path_mount+0xd26/0x10a0 fs/namespace.c:3290 do_mount fs/namespace.c:3355 [inline] __do_sys_mount fs/namespace.c:3563 [inline] __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 ((console_sem).lock){-.-.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:138 __down_trylock_console_sem+0x105/0x250 kernel/printk/printk.c:239 console_trylock kernel/printk/printk.c:2575 [inline] console_trylock_spinning+0x8a/0x3f0 kernel/printk/printk.c:1867 vprintk_emit+0xa6/0x150 kernel/printk/printk.c:2273 _printk+0xd1/0x120 kernel/printk/printk.c:2299 report_bug+0x1e5/0x2e0 lib/bug.c:195 handle_bug+0x3d/0x70 arch/x86/kernel/traps.c:239 exc_invalid_op+0x16/0x40 arch/x86/kernel/traps.c:259 asm_exc_invalid_op+0x16/0x20 arch/x86/include/asm/idtentry.h:604 copy_from_user_nofault+0x15c/0x1c0 bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline] ____bpf_probe_read_user kernel/trace/bpf_trace.c:166 [inline] bpf_probe_read_user+0x26/0x70 kernel/trace/bpf_trace.c:163 bpf_prog_078a3568a35342ea+0x38/0xdfc bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1916 __traceiter_timer_start+0x79/0xd0 include/trace/events/timer.h:52 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x3ae/0x540 kernel/time/timer.c:586 internal_add_timer kernel/time/timer.c:611 [inline] __mod_timer+0xa60/0xeb0 kernel/time/timer.c:1062 mrp_join_timer_arm net/802/mrp.c:596 [inline] mrp_join_timer+0x14b/0x180 net/802/mrp.c:611 call_timer_fn+0x16d/0x560 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x67c/0x890 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x3a7/0x930 kernel/softirq.c:558 __do_softirq kernel/softirq.c:592 [inline] invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x157/0x240 kernel/softirq.c:641 irq_exit_rcu+0x5/0x20 kernel/softirq.c:653 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 kernfs_dop_revalidate+0x1/0x4a0 fs/kernfs/dir.c:1057 d_revalidate fs/namei.c:856 [inline] lookup_fast+0x37b/0x7b0 fs/namei.c:1624 walk_component+0x115/0x610 fs/namei.c:1972 lookup_last fs/namei.c:2431 [inline] path_lookupat+0x16f/0x450 fs/namei.c:2455 filename_lookup+0x230/0x5c0 fs/namei.c:2484 user_path_at_empty+0x40/0x180 fs/namei.c:2883 do_readlinkat+0x114/0x3a0 fs/stat.c:442 __do_sys_readlink fs/stat.c:475 [inline] __se_sys_readlink fs/stat.c:472 [inline] __x64_sys_readlink+0x7b/0x90 fs/stat.c:472 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 other info that might help us debug this: Chain exists of: (console_sem).lock --> &rq->__lock --> &base->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&base->lock); lock(&rq->__lock); lock(&base->lock); lock((console_sem).lock); *** DEADLOCK *** 4 locks held by udevd/3544: #0: ffffc90000dd0be0 ((&app->join_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline] #0: ffffc90000dd0be0 ((&app->join_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbe/0x560 kernel/time/timer.c:1441 #1: ffff888062fa54c8 (&app->lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #1: ffff888062fa54c8 (&app->lock){+.-.}-{2:2}, at: mrp_join_timer+0xc8/0x180 net/802/mrp.c:609 #2: ffff8880b9128098 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x120/0x260 kernel/time/timer.c:946 #3: ffffffff8c91fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311 stack backtrace: CPU: 1 PID: 3544 Comm: udevd Not tainted 5.15.172-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 down_trylock+0x1c/0xa0 kernel/locking/semaphore.c:138 __down_trylock_console_sem+0x105/0x250 kernel/printk/printk.c:239 console_trylock kernel/printk/printk.c:2575 [inline] console_trylock_spinning+0x8a/0x3f0 kernel/printk/printk.c:1867 vprintk_emit+0xa6/0x150 kernel/printk/printk.c:2273 _printk+0xd1/0x120 kernel/printk/printk.c:2299 report_bug+0x1e5/0x2e0 lib/bug.c:195 handle_bug+0x3d/0x70 arch/x86/kernel/traps.c:239 exc_invalid_op+0x16/0x40 arch/x86/kernel/traps.c:259 asm_exc_invalid_op+0x16/0x20 arch/x86/include/asm/idtentry.h:604 RIP: 0010:copy_from_user_nofault+0x15c/0x1c0 mm/maccess.c:226 Code: db 48 c7 c0 f2 ff ff ff 48 0f 44 c5 eb 0c e8 0b c7 d5 ff 48 c7 c0 f2 ff ff ff 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 f4 c6 d5 ff <0f> 0b e9 1e ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c ef fe ff RSP: 0018:ffffc90000dd0828 EFLAGS: 00010046 RAX: ffffffff81aaacac RBX: 0000000000000000 RCX: ffff88807d50d940 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: dffffc0000000000 R08: ffffffff81aaabbd R09: fffffbfff20ec821 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000020000000 R13: 0000000000000008 R14: 0000000020000000 R15: ffffc90000dd0888 bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline] ____bpf_probe_read_user kernel/trace/bpf_trace.c:166 [inline] bpf_probe_read_user+0x26/0x70 kernel/trace/bpf_trace.c:163 bpf_prog_078a3568a35342ea+0x38/0xdfc bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1916 __traceiter_timer_start+0x79/0xd0 include/trace/events/timer.h:52 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x3ae/0x540 kernel/time/timer.c:586 internal_add_timer kernel/time/timer.c:611 [inline] __mod_timer+0xa60/0xeb0 kernel/time/timer.c:1062 mrp_join_timer_arm net/802/mrp.c:596 [inline] mrp_join_timer+0x14b/0x180 net/802/mrp.c:611 call_timer_fn+0x16d/0x560 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x67c/0x890 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x3a7/0x930 kernel/softirq.c:558 __do_softirq kernel/softirq.c:592 [inline] invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x157/0x240 kernel/softirq.c:641 irq_exit_rcu+0x5/0x20 kernel/softirq.c:653 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:kernfs_dop_revalidate+0x1/0x4a0 fs/kernfs/dir.c:1057 Code: 41 5f 5d c3 44 89 f9 80 e1 07 fe c1 38 c1 0f 8c 24 ff ff ff 4c 89 ff e8 ad 92 cd ff e9 17 ff ff ff 0f 1f 84 00 00 00 00 00 55 <41> 57 41 56 41 55 41 54 53 89 f5 49 89 fd e8 1c bb 83 ff 89 ee 83 RSP: 0018:ffffc90002dc7970 EFLAGS: 00000246 RAX: 1ffffffff15334e8 RBX: ffffffff8a99a740 RCX: ffff88807d50d940 RDX: 0000000000000000 RSI: 0000000000004000 RDI: ffff8880653422f0 RBP: ffffc90002dc7a50 R08: ffffffff81d9fbcf R09: fffffbfff1bd2d3e R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000004000 R13: ffffc90002dc7c50 R14: dffffc0000000000 R15: dffffc0000000000 d_revalidate fs/namei.c:856 [inline] lookup_fast+0x37b/0x7b0 fs/namei.c:1624 walk_component+0x115/0x610 fs/namei.c:1972 lookup_last fs/namei.c:2431 [inline] path_lookupat+0x16f/0x450 fs/namei.c:2455 filename_lookup+0x230/0x5c0 fs/namei.c:2484 user_path_at_empty+0x40/0x180 fs/namei.c:2883 do_readlinkat+0x114/0x3a0 fs/stat.c:442 __do_sys_readlink fs/stat.c:475 [inline] __se_sys_readlink fs/stat.c:472 [inline] __x64_sys_readlink+0x7b/0x90 fs/stat.c:472 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fc45fdaad47 Code: 73 01 c3 48 8b 0d e1 90 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 59 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b1 90 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007fffe2fbc178 EFLAGS: 00000246 ORIG_RAX: 0000000000000059 RAX: ffffffffffffffda RBX: 00007fffe2fbc188 RCX: 00007fc45fdaad47 RDX: 0000000000000400 RSI: 00007fffe2fbc188 RDI: 00007fffe2fbc668 RBP: 0000000000000400 R08: 0000558b17462124 R09: 0000000000000000 R10: 0000000000000812 R11: 0000000000000246 R12: 00007fffe2fbc668 R13: 00007fffe2fbc5d8 R14: 0000558b17456910 R15: 0000000000000000 WARNING: CPU: 1 PID: 3544 at mm/maccess.c:226 copy_from_user_nofault+0x15c/0x1c0 Modules linked in: CPU: 1 PID: 3544 Comm: udevd Not tainted 5.15.172-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:copy_from_user_nofault+0x15c/0x1c0 mm/maccess.c:226 Code: db 48 c7 c0 f2 ff ff ff 48 0f 44 c5 eb 0c e8 0b c7 d5 ff 48 c7 c0 f2 ff ff ff 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 f4 c6 d5 ff <0f> 0b e9 1e ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c ef fe ff RSP: 0018:ffffc90000dd0828 EFLAGS: 00010046 RAX: ffffffff81aaacac RBX: 0000000000000000 RCX: ffff88807d50d940 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: dffffc0000000000 R08: ffffffff81aaabbd R09: fffffbfff20ec821 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000020000000 R13: 0000000000000008 R14: 0000000020000000 R15: ffffc90000dd0888 FS: 00007fc45fc7ec80(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3ce80d CR3: 0000000025a27000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: bpf_probe_read_user_common kernel/trace/bpf_trace.c:157 [inline] ____bpf_probe_read_user kernel/trace/bpf_trace.c:166 [inline] bpf_probe_read_user+0x26/0x70 kernel/trace/bpf_trace.c:163 bpf_prog_078a3568a35342ea+0x38/0xdfc bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1916 __traceiter_timer_start+0x79/0xd0 include/trace/events/timer.h:52 trace_timer_start include/trace/events/timer.h:52 [inline] enqueue_timer+0x3ae/0x540 kernel/time/timer.c:586 internal_add_timer kernel/time/timer.c:611 [inline] __mod_timer+0xa60/0xeb0 kernel/time/timer.c:1062 mrp_join_timer_arm net/802/mrp.c:596 [inline] mrp_join_timer+0x14b/0x180 net/802/mrp.c:611 call_timer_fn+0x16d/0x560 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x67c/0x890 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x3a7/0x930 kernel/softirq.c:558 __do_softirq kernel/softirq.c:592 [inline] invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x157/0x240 kernel/softirq.c:641 irq_exit_rcu+0x5/0x20 kernel/softirq.c:653 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:kernfs_dop_revalidate+0x1/0x4a0 fs/kernfs/dir.c:1057 Code: 41 5f 5d c3 44 89 f9 80 e1 07 fe c1 38 c1 0f 8c 24 ff ff ff 4c 89 ff e8 ad 92 cd ff e9 17 ff ff ff 0f 1f 84 00 00 00 00 00 55 <41> 57 41 56 41 55 41 54 53 89 f5 49 89 fd e8 1c bb 83 ff 89 ee 83 RSP: 0018:ffffc90002dc7970 EFLAGS: 00000246 RAX: 1ffffffff15334e8 RBX: ffffffff8a99a740 RCX: ffff88807d50d940 RDX: 0000000000000000 RSI: 0000000000004000 RDI: ffff8880653422f0 RBP: ffffc90002dc7a50 R08: ffffffff81d9fbcf R09: fffffbfff1bd2d3e R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000004000 R13: ffffc90002dc7c50 R14: dffffc0000000000 R15: dffffc0000000000 d_revalidate fs/namei.c:856 [inline] lookup_fast+0x37b/0x7b0 fs/namei.c:1624 walk_component+0x115/0x610 fs/namei.c:1972 lookup_last fs/namei.c:2431 [inline] path_lookupat+0x16f/0x450 fs/namei.c:2455 filename_lookup+0x230/0x5c0 fs/namei.c:2484 user_path_at_empty+0x40/0x180 fs/namei.c:2883 do_readlinkat+0x114/0x3a0 fs/stat.c:442 __do_sys_readlink fs/stat.c:475 [inline] __se_sys_readlink fs/stat.c:472 [inline] __x64_sys_readlink+0x7b/0x90 fs/stat.c:472 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fc45fdaad47 Code: 73 01 c3 48 8b 0d e1 90 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 59 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b1 90 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007fffe2fbc178 EFLAGS: 00000246 ORIG_RAX: 0000000000000059 RAX: ffffffffffffffda RBX: 00007fffe2fbc188 RCX: 00007fc45fdaad47 RDX: 0000000000000400 RSI: 00007fffe2fbc188 RDI: 00007fffe2fbc668 RBP: 0000000000000400 R08: 0000558b17462124 R09: 0000000000000000 R10: 0000000000000812 R11: 0000000000000246 R12: 00007fffe2fbc668 R13: 00007fffe2fbc5d8 R14: 0000558b17456910 R15: 0000000000000000 ---------------- Code disassembly (best guess): 0: 41 5f pop %r15 2: 5d pop %rbp 3: c3 ret 4: 44 89 f9 mov %r15d,%ecx 7: 80 e1 07 and $0x7,%cl a: fe c1 inc %cl c: 38 c1 cmp %al,%cl e: 0f 8c 24 ff ff ff jl 0xffffff38 14: 4c 89 ff mov %r15,%rdi 17: e8 ad 92 cd ff call 0xffcd92c9 1c: e9 17 ff ff ff jmp 0xffffff38 21: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1) 28: 00 29: 55 push %rbp * 2a: 41 57 push %r15 <-- trapping instruction 2c: 41 56 push %r14 2e: 41 55 push %r13 30: 41 54 push %r12 32: 53 push %rbx 33: 89 f5 mov %esi,%ebp 35: 49 89 fd mov %rdi,%r13 38: e8 1c bb 83 ff call 0xff83bb59 3d: 89 ee mov %ebp,%esi 3f: 83 .byte 0x83