Extracting prog: 8m41.937276027s
Minimizing prog: 6m26.793544946s
Simplifying prog options: 3m51.52484213s
Extracting C: 1m25.181567337s
Simplifying C: 0s
extracting reproducer from 25 programs
testing a last program of every proc
single: executing 5 programs separately with timeout 6m0s
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): openat$sndseq-ioctl$SNDRV_SEQ_IOCTL_CREATE_QUEUE-write$sndseq-ioctl$SNDRV_SEQ_IOCTL_SET_QUEUE_TEMPO
detailed listing:
executing program 0:
r0 = openat$sndseq(0xffffffffffffff9c, &(0x7f00000018c0), 0xe0c81)
ioctl$SNDRV_SEQ_IOCTL_CREATE_QUEUE(r0, 0xc08c5332, &(0x7f0000000380)={0xfffffff8, 0x0, 0x0, 'queue0\x00'})
write$sndseq(r0, &(0x7f0000000000)=[{0x1e, 0x0, 0x0, 0x0, @tick, {}, {}, @raw32}], 0x1001a)
ioctl$SNDRV_SEQ_IOCTL_SET_QUEUE_TEMPO(r0, 0x402c5342, &(0x7f0000000040)={0x0, 0x7a120, 0x7ff, {0xfffffff8, 0xffffffff}})
program did not crash
testing program (duration=6m0s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): setns-socket-ioctl$VFAT_IOCTL_READDIR_BOTH-write$nbd
detailed listing:
executing program 0:
setns(0xc9, 0x0)
r0 = socket(0x8, 0x5, 0x5)
ioctl$VFAT_IOCTL_READDIR_BOTH(r0, 0x6180, 0x0)
write$nbd(r0, &(0x7f0000000100)={0x67446698, 0x1, 0x3, 0x4, 0x1}, 0x10)
program crashed: general protection fault in atmtcp_ioctl
single: successfully extracted reproducer
found reproducer with 4 syscalls
minimizing guilty program
testing program (duration=1m16.989020024s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): setns-socket-ioctl$VFAT_IOCTL_READDIR_BOTH
detailed listing:
executing program 0:
setns(0xc9, 0x0)
r0 = socket(0x8, 0x5, 0x5)
ioctl$VFAT_IOCTL_READDIR_BOTH(r0, 0x6180, 0x0)
program crashed: general protection fault in atmtcp_ioctl
testing program (duration=1m16.989020024s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): setns-socket
detailed listing:
executing program 0:
setns(0xc9, 0x0)
socket(0x8, 0x5, 0x5)
program did not crash
testing program (duration=1m16.989020024s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): setns-ioctl$VFAT_IOCTL_READDIR_BOTH
detailed listing:
executing program 0:
setns(0xc9, 0x0)
ioctl$VFAT_IOCTL_READDIR_BOTH(0xffffffffffffffff, 0x6180, 0x0)
program did not crash
testing program (duration=1m16.989020024s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket-ioctl$VFAT_IOCTL_READDIR_BOTH
detailed listing:
executing program 0:
r0 = socket(0x8, 0x5, 0x5)
ioctl$VFAT_IOCTL_READDIR_BOTH(r0, 0x6180, 0x0)
program did not crash
extracting C reproducer
testing compiled C program (duration=1m16.989020024s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): setns-socket-ioctl$VFAT_IOCTL_READDIR_BOTH
program did not crash
simplifying guilty program options
testing program (duration=1m16.989020024s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): setns-socket-ioctl$VFAT_IOCTL_READDIR_BOTH
detailed listing:
executing program 0:
setns(0xc9, 0x0)
r0 = socket(0x8, 0x5, 0x5)
ioctl$VFAT_IOCTL_READDIR_BOTH(r0, 0x6180, 0x0)
program crashed: general protection fault in atmtcp_ioctl
extracting C reproducer
testing compiled C program (duration=1m16.989020024s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): setns-socket-ioctl$VFAT_IOCTL_READDIR_BOTH
program did not crash
testing program (duration=1m16.989020024s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): setns-socket-ioctl$VFAT_IOCTL_READDIR_BOTH
detailed listing:
executing program 0:
setns(0xc9, 0x0)
r0 = socket(0x8, 0x5, 0x5)
ioctl$VFAT_IOCTL_READDIR_BOTH(r0, 0x6180, 0x0)
program did not crash
testing program (duration=1m16.989020024s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): setns-socket-ioctl$VFAT_IOCTL_READDIR_BOTH
detailed listing:
executing program 0:
setns(0xc9, 0x0)
r0 = socket(0x8, 0x5, 0x5)
ioctl$VFAT_IOCTL_READDIR_BOTH(r0, 0x6180, 0x0)
program crashed: general protection fault in atmtcp_ioctl
validation run: crashed=true
testing program (duration=1m16.989020024s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): setns-socket-ioctl$VFAT_IOCTL_READDIR_BOTH
detailed listing:
executing program 0:
setns(0xc9, 0x0)
r0 = socket(0x8, 0x5, 0x5)
ioctl$VFAT_IOCTL_READDIR_BOTH(r0, 0x6180, 0x0)
program crashed: general protection fault in atmtcp_ioctl
validation run: crashed=true
testing program (duration=1m16.989020024s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): setns-socket-ioctl$VFAT_IOCTL_READDIR_BOTH
detailed listing:
executing program 0:
setns(0xc9, 0x0)
r0 = socket(0x8, 0x5, 0x5)
ioctl$VFAT_IOCTL_READDIR_BOTH(r0, 0x6180, 0x0)
program crashed: general protection fault in atmtcp_ioctl
validation run: crashed=true
reproducing took 25m34.021118646s
repro crashed as (corrupted=false):
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: 6148 Comm: syz.1.185 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:atmtcp_attach drivers/atm/atmtcp.c:408 [inline]
RIP: 0010:atmtcp_ioctl+0x84e/0xdd0 drivers/atm/atmtcp.c:477
Code: ff e9 bf fb ff ff 4c 8d 63 20 4c 89 e0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 e7 e8 7d 98 83 fb 4d 8b 24 24 4c 89 e0 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 e7 e8 64 98 83 fb 49 83 3c 24 00 0f 84 e1
RSP: 0018:ffffc90004ed7c58 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88806b290000 RCX: ffffffff8a99ef04
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc90004ed7ba0
RBP: dffffc0000000000 R08: ffffc90004ed7ba7 R09: 1ffff920009daf74
R10: dffffc0000000000 R11: fffff520009daf75 R12: 0000000000000000
R13: 1ffff1100d652000 R14: ffff8880778b8600 R15: ffff88807bc57000
FS: 000055556ac18500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff36906ff8 CR3: 0000000076b77000 CR4: 00000000003506f0
Call Trace:
do_vcc_ioctl+0x383/0x9e0 net/atm/ioctl.c:159
sock_do_ioctl+0xfc/0x310 net/socket.c:1220
sock_ioctl+0x5be/0x7e0 net/socket.c:1341
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8e4b19e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff57650b68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8e4b425fa0 RCX: 00007f8e4b19e159
RDX: 0000000000000000 RSI: 0000000000006180 RDI: 0000000000000003
RBP: 00007f8e4b23506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8e4b425fac R14: 00007f8e4b425fa0 R15: 00007f8e4b425fa0
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:atmtcp_attach drivers/atm/atmtcp.c:408 [inline]
RIP: 0010:atmtcp_ioctl+0x84e/0xdd0 drivers/atm/atmtcp.c:477
Code: ff e9 bf fb ff ff 4c 8d 63 20 4c 89 e0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 e7 e8 7d 98 83 fb 4d 8b 24 24 4c 89 e0 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 e7 e8 64 98 83 fb 49 83 3c 24 00 0f 84 e1
RSP: 0018:ffffc90004ed7c58 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88806b290000 RCX: ffffffff8a99ef04
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc90004ed7ba0
RBP: dffffc0000000000 R08: ffffc90004ed7ba7 R09: 1ffff920009daf74
R10: dffffc0000000000 R11: fffff520009daf75 R12: 0000000000000000
R13: 1ffff1100d652000 R14: ffff8880778b8600 R15: ffff88807bc57000
FS: 000055556ac18500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff36906ff8 CR3: 0000000076b77000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
0: ff ljmp (bad)
1: e9 bf fb ff ff jmp 0xfffffbc5
6: 4c 8d 63 20 lea 0x20(%rbx),%r12
a: 4c 89 e0 mov %r12,%rax
d: 48 c1 e8 03 shr $0x3,%rax
11: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1)
15: 74 08 je 0x1f
17: 4c 89 e7 mov %r12,%rdi
1a: e8 7d 98 83 fb call 0xfb83989c
1f: 4d 8b 24 24 mov (%r12),%r12
23: 4c 89 e0 mov %r12,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 e7 mov %r12,%rdi
33: e8 64 98 83 fb call 0xfb83989c
38: 49 83 3c 24 00 cmpq $0x0,(%r12)
3d: 0f .byte 0xf
3e: 84 e1 test %ah,%cl
final repro crashed as (corrupted=false):
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: 6148 Comm: syz.1.185 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:atmtcp_attach drivers/atm/atmtcp.c:408 [inline]
RIP: 0010:atmtcp_ioctl+0x84e/0xdd0 drivers/atm/atmtcp.c:477
Code: ff e9 bf fb ff ff 4c 8d 63 20 4c 89 e0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 e7 e8 7d 98 83 fb 4d 8b 24 24 4c 89 e0 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 e7 e8 64 98 83 fb 49 83 3c 24 00 0f 84 e1
RSP: 0018:ffffc90004ed7c58 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88806b290000 RCX: ffffffff8a99ef04
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc90004ed7ba0
RBP: dffffc0000000000 R08: ffffc90004ed7ba7 R09: 1ffff920009daf74
R10: dffffc0000000000 R11: fffff520009daf75 R12: 0000000000000000
R13: 1ffff1100d652000 R14: ffff8880778b8600 R15: ffff88807bc57000
FS: 000055556ac18500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff36906ff8 CR3: 0000000076b77000 CR4: 00000000003506f0
Call Trace:
do_vcc_ioctl+0x383/0x9e0 net/atm/ioctl.c:159
sock_do_ioctl+0xfc/0x310 net/socket.c:1220
sock_ioctl+0x5be/0x7e0 net/socket.c:1341
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8e4b19e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff57650b68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8e4b425fa0 RCX: 00007f8e4b19e159
RDX: 0000000000000000 RSI: 0000000000006180 RDI: 0000000000000003
RBP: 00007f8e4b23506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8e4b425fac R14: 00007f8e4b425fa0 R15: 00007f8e4b425fa0
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:atmtcp_attach drivers/atm/atmtcp.c:408 [inline]
RIP: 0010:atmtcp_ioctl+0x84e/0xdd0 drivers/atm/atmtcp.c:477
Code: ff e9 bf fb ff ff 4c 8d 63 20 4c 89 e0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 e7 e8 7d 98 83 fb 4d 8b 24 24 4c 89 e0 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 e7 e8 64 98 83 fb 49 83 3c 24 00 0f 84 e1
RSP: 0018:ffffc90004ed7c58 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88806b290000 RCX: ffffffff8a99ef04
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc90004ed7ba0
RBP: dffffc0000000000 R08: ffffc90004ed7ba7 R09: 1ffff920009daf74
R10: dffffc0000000000 R11: fffff520009daf75 R12: 0000000000000000
R13: 1ffff1100d652000 R14: ffff8880778b8600 R15: ffff88807bc57000
FS: 000055556ac18500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff36906ff8 CR3: 0000000076b77000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
0: ff ljmp (bad)
1: e9 bf fb ff ff jmp 0xfffffbc5
6: 4c 8d 63 20 lea 0x20(%rbx),%r12
a: 4c 89 e0 mov %r12,%rax
d: 48 c1 e8 03 shr $0x3,%rax
11: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1)
15: 74 08 je 0x1f
17: 4c 89 e7 mov %r12,%rdi
1a: e8 7d 98 83 fb call 0xfb83989c
1f: 4d 8b 24 24 mov (%r12),%r12
23: 4c 89 e0 mov %r12,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 e7 mov %r12,%rdi
33: e8 64 98 83 fb call 0xfb83989c
38: 49 83 3c 24 00 cmpq $0x0,(%r12)
3d: 0f .byte 0xf
3e: 84 e1 test %ah,%cl