================================================================== BUG: KASAN: use-after-free in fast_dput+0x1e9/0x290 fs/dcache.c:750 Read of size 4 at addr ffff88811c8d0770 by task syz.4.178/1122 CPU: 1 PID: 1122 Comm: syz.4.178 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:77 dump_stack_lvl+0x1a7/0x208 lib/dump_stack.c:118 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0xe2/0x130 mm/kasan/report.c:452 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308 fast_dput+0x1e9/0x290 fs/dcache.c:750 dput+0x21/0x80 fs/dcache.c:870 path_put+0x39/0x60 fs/namei.c:499 dentry_release+0x4f/0xa0 fs/incfs/vfs.c:1591 __dentry_kill+0x4b5/0x650 fs/dcache.c:588 shrink_dentry_list+0x38e/0x500 fs/dcache.c:1146 shrink_dcache_parent+0xa9/0x270 fs/dcache.c:-1 do_one_tree+0x27/0x150 fs/dcache.c:1627 shrink_dcache_for_umount+0x6a/0x110 fs/dcache.c:1644 generic_shutdown_super+0x66/0x320 fs/super.c:447 kill_anon_super+0x3a/0x70 fs/super.c:1131 incfs_kill_sb+0x4c/0x210 fs/incfs/vfs.c:1965 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0xaf/0xe0 fs/super.c:366 cleanup_mnt+0x45b/0x510 fs/namespace.c:1123 __cleanup_mnt+0x19/0x20 fs/namespace.c:1130 task_work_run+0x127/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa90/0x2500 kernel/exit.c:872 do_group_exit+0x141/0x310 kernel/exit.c:986 get_signal+0xf7d/0x12e0 kernel/signal.c:2793 arch_do_signal_or_restart+0xe2/0x11d0 arch/x86/kernel/signal.c:805 handle_signal_work kernel/entry/common.c:145 [inline] exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fcf0129cfce Code: Unable to access opcode bytes at RIP 0x7fcf0129cfa4. RSP: 002b:00007fceffcf4f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007fceffcf56c0 RCX: 00007fcf0129cfce RDX: 00007fceffcf4fb0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fcf01372bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcf01556218 R14: 00007fcf01556180 R15: 00007fff4696dbe8 Allocated by task 1388: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:430 [inline] __kasan_slab_alloc+0xbd/0xf0 mm/kasan/common.c:463 kasan_slab_alloc include/linux/kasan.h:244 [inline] slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:580 slab_alloc_node mm/slub.c:2952 [inline] slab_alloc mm/slub.c:2960 [inline] kmem_cache_alloc+0x162/0x2d0 mm/slub.c:2965 __d_alloc+0x2d/0x6a0 fs/dcache.c:1714 d_alloc+0x4b/0x260 fs/dcache.c:1793 __lookup_hash+0xcb/0x250 fs/namei.c:1545 filename_create+0x1d5/0x680 fs/namei.c:3616 user_path_create fs/namei.c:3673 [inline] do_mkdirat+0x5e/0x340 fs/namei.c:3813 __do_sys_mkdirat fs/namei.c:3831 [inline] __se_sys_mkdirat fs/namei.c:3829 [inline] __x64_sys_mkdirat+0x7b/0x90 fs/namei.c:3829 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 1446: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4a/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370 kasan_slab_free include/linux/kasan.h:220 [inline] slab_free_hook mm/slub.c:1600 [inline] slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1626 slab_free mm/slub.c:3208 [inline] kmem_cache_free+0x100/0x2d0 mm/slub.c:3224 __d_free+0x23/0x30 fs/dcache.c:271 rcu_do_batch+0x4ef/0xab0 kernel/rcu/tree.c:2494 rcu_core+0x577/0xd80 kernel/rcu/tree.c:2735 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2748 __do_softirq+0x255/0x563 kernel/softirq.c:309 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu kernel/rcu/tree.c:2980 [inline] call_rcu+0x11a/0x10b0 kernel/rcu/tree.c:3054 dentry_free+0xbd/0x150 fs/dcache.c:-1 __dentry_kill+0x50a/0x650 fs/dcache.c:597 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1 dput+0x42/0x80 fs/dcache.c:883 do_rmdir+0x24b/0x630 fs/namei.c:3922 __do_sys_unlinkat fs/namei.c:4084 [inline] __se_sys_unlinkat fs/namei.c:4078 [inline] __x64_sys_unlinkat+0xc7/0xf0 fs/namei.c:4078 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff88811c8d0770 which belongs to the cache dentry of size 208 The buggy address is located 0 bytes inside of 208-byte region [ffff88811c8d0770, ffff88811c8d0840) The buggy address belongs to the page: page:ffffea0004723400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11c8d0 flags: 0x4000000000000200(slab) raw: 4000000000000200 ffffea0004723440 0000000300000003 ffff88810018b500 raw: 0000000000000000 00000000000f000f 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Reclaimable, gfp_mask 0x12cd0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_RECLAIMABLE), pid 278, ts 20155883617, free_ts 0 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x179/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x223b/0x23d0 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x290/0x620 mm/page_alloc.c:5370 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1813 [inline] new_slab+0x84/0x3f0 mm/slub.c:1874 new_slab_objects mm/slub.c:2632 [inline] ___slab_alloc+0x2a6/0x450 mm/slub.c:2796 __slab_alloc+0x63/0xa0 mm/slub.c:2836 slab_alloc_node mm/slub.c:2918 [inline] slab_alloc mm/slub.c:2960 [inline] kmem_cache_alloc+0x1ac/0x2d0 mm/slub.c:2965 __d_alloc+0x2d/0x6a0 fs/dcache.c:1714 d_alloc_pseudo+0x1d/0x70 fs/dcache.c:1845 alloc_file_pseudo+0xe0/0x200 fs/file_table.c:226 sock_alloc_file+0xba/0x260 net/socket.c:412 sock_map_fd net/socket.c:436 [inline] __sys_socket+0x12b/0x190 net/socket.c:1533 __do_sys_socket net/socket.c:1538 [inline] __se_sys_socket net/socket.c:1536 [inline] __x64_sys_socket+0x7a/0x90 net/socket.c:1536 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xcb page_owner free stack trace missing Memory state around the buggy address: ffff88811c8d0600: 00 00 00 00 fc fc fc fc fc fc fc fc fa fb fb fb ffff88811c8d0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88811c8d0700: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fa fb ^ ffff88811c8d0780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811c8d0800: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ================================================================== ------------[ cut here ]------------ WARNING: CPU: 1 PID: 1122 at fs/dcache.c:766 fast_dput+0x210/0x290 fs/dcache.c:766 Modules linked in: CPU: 1 PID: 1122 Comm: syz.4.178 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:fast_dput+0x210/0x290 fs/dcache.c:766 Code: d5 f2 ff e9 46 fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 99 fe ff ff 48 89 df e8 8a d5 f2 ff e9 8c fe ff ff e8 70 54 b8 ff <0f> 0b e9 0b ff ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c e4 fe ff RSP: 0018:ffffc900013ef5b8 EFLAGS: 00010293 RAX: ffffffff81ac61e0 RBX: ffff88811c8d0770 RCX: ffff8881145aa780 RDX: 0000000000000000 RSI: 00000000ffffff80 RDI: 0000000000000001 RBP: ffffc900013ef5e8 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200027dea8 R12: 00000000ffffff80 R13: dffffc0000000000 R14: ffff88811c8d07c8 R15: 1ffff1102391a0f9 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3114e8 CR3: 000000000640f000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: dput+0x21/0x80 fs/dcache.c:870 path_put+0x39/0x60 fs/namei.c:499 dentry_release+0x4f/0xa0 fs/incfs/vfs.c:1591 __dentry_kill+0x4b5/0x650 fs/dcache.c:588 shrink_dentry_list+0x38e/0x500 fs/dcache.c:1146 shrink_dcache_parent+0xa9/0x270 fs/dcache.c:-1 do_one_tree+0x27/0x150 fs/dcache.c:1627 shrink_dcache_for_umount+0x6a/0x110 fs/dcache.c:1644 generic_shutdown_super+0x66/0x320 fs/super.c:447 kill_anon_super+0x3a/0x70 fs/super.c:1131 incfs_kill_sb+0x4c/0x210 fs/incfs/vfs.c:1965 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0xaf/0xe0 fs/super.c:366 cleanup_mnt+0x45b/0x510 fs/namespace.c:1123 __cleanup_mnt+0x19/0x20 fs/namespace.c:1130 task_work_run+0x127/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa90/0x2500 kernel/exit.c:872 do_group_exit+0x141/0x310 kernel/exit.c:986 get_signal+0xf7d/0x12e0 kernel/signal.c:2793 arch_do_signal_or_restart+0xe2/0x11d0 arch/x86/kernel/signal.c:805 handle_signal_work kernel/entry/common.c:145 [inline] exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fcf0129cfce Code: Unable to access opcode bytes at RIP 0x7fcf0129cfa4. RSP: 002b:00007fceffcf4f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007fceffcf56c0 RCX: 00007fcf0129cfce RDX: 00007fceffcf4fb0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fcf01372bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcf01556218 R14: 00007fcf01556180 R15: 00007fff4696dbe8 ---[ end trace 5d28f926b7ebfd04 ]--- ------------[ cut here ]------------ WARNING: CPU: 1 PID: 1122 at fs/inode.c:304 drop_nlink+0xc5/0x110 fs/inode.c:304 Modules linked in: CPU: 1 PID: 1122 Comm: syz.4.178 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:drop_nlink+0xc5/0x110 fs/inode.c:304 Code: 1b 48 8d bb b8 04 00 00 be 08 00 00 00 e8 13 f1 f1 ff f0 48 ff 83 b8 04 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 cb 6d b7 ff <0f> 0b eb 86 44 89 f1 80 e1 07 80 c1 03 38 c1 0f 8c 5e ff ff ff 4c RSP: 0018:ffffc900013ef808 EFLAGS: 00010293 RAX: ffffffff81ad4885 RBX: ffff88811de25620 RCX: ffff8881145aa780 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900013ef830 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200027def0 R12: dffffc0000000000 R13: 1ffff11023bc4acd R14: ffff88811de25668 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3114e8 CR3: 000000000640f000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: shmem_rmdir+0x5b/0x90 mm/shmem.c:3011 vfs_rmdir+0x1b3/0x3e0 fs/namei.c:3860 incfs_kill_sb+0xfe/0x210 fs/incfs/vfs.c:1973 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0xaf/0xe0 fs/super.c:366 cleanup_mnt+0x45b/0x510 fs/namespace.c:1123 __cleanup_mnt+0x19/0x20 fs/namespace.c:1130 task_work_run+0x127/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa90/0x2500 kernel/exit.c:872 do_group_exit+0x141/0x310 kernel/exit.c:986 get_signal+0xf7d/0x12e0 kernel/signal.c:2793 arch_do_signal_or_restart+0xe2/0x11d0 arch/x86/kernel/signal.c:805 handle_signal_work kernel/entry/common.c:145 [inline] exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fcf0129cfce Code: Unable to access opcode bytes at RIP 0x7fcf0129cfa4. RSP: 002b:00007fceffcf4f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007fceffcf56c0 RCX: 00007fcf0129cfce RDX: 00007fceffcf4fb0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fcf01372bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcf01556218 R14: 00007fcf01556180 R15: 00007fff4696dbe8 ---[ end trace 5d28f926b7ebfd05 ]--- BUG: kernel NULL pointer dereference, address: 0000000000000170 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP KASAN CPU: 1 PID: 1122 Comm: syz.4.178 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:arch_atomic_add_return arch/x86/include/asm/atomic.h:165 [inline] RIP: 0010:arch_atomic_inc_return include/linux/atomic-arch-fallback.h:286 [inline] RIP: 0010:atomic_inc_return include/asm-generic/atomic-instrumented.h:251 [inline] RIP: 0010:ihold+0x26/0x60 fs/inode.c:423 Code: 00 00 00 00 55 48 89 e5 41 56 53 48 89 fb e8 e1 65 b7 ff 48 8d bb 70 01 00 00 be 04 00 00 00 e8 00 e9 f1 ff 41 be 01 00 00 00 44 0f c1 b3 70 01 00 00 41 ff c6 bf 02 00 00 00 44 89 f6 e8 61 RSP: 0018:ffffc900013ef848 EFLAGS: 00010202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000286 RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000170 RBP: ffffc900013ef858 R08: 0000000000000000 R09: 1ffff11023914471 R10: dffffc0000000000 R11: ffffed1023914472 R12: 1ffff110260c9916 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000170 CR3: 000000000640f000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: d_delete_notify include/linux/fsnotify.h:264 [inline] vfs_rmdir+0x247/0x3e0 fs/namei.c:3873 incfs_kill_sb+0xfe/0x210 fs/incfs/vfs.c:1973 deactivate_locked_super+0xa0/0x100 fs/super.c:335 deactivate_super+0xaf/0xe0 fs/super.c:366 cleanup_mnt+0x45b/0x510 fs/namespace.c:1123 __cleanup_mnt+0x19/0x20 fs/namespace.c:1130 task_work_run+0x127/0x190 kernel/task_work.c:189 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa90/0x2500 kernel/exit.c:872 do_group_exit+0x141/0x310 kernel/exit.c:986 get_signal+0xf7d/0x12e0 kernel/signal.c:2793 arch_do_signal_or_restart+0xe2/0x11d0 arch/x86/kernel/signal.c:805 handle_signal_work kernel/entry/common.c:145 [inline] exit_to_user_mode_loop+0xa2/0xe0 kernel/entry/common.c:169 exit_to_user_mode_prepare+0x76/0xa0 kernel/entry/common.c:199 syscall_exit_to_user_mode+0x1d/0x40 kernel/entry/common.c:274 do_syscall_64+0x3d/0x40 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fcf0129cfce Code: Unable to access opcode bytes at RIP 0x7fcf0129cfa4. RSP: 002b:00007fceffcf4f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007fceffcf56c0 RCX: 00007fcf0129cfce RDX: 00007fceffcf4fb0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fcf01372bd9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcf01556218 R14: 00007fcf01556180 R15: 00007fff4696dbe8 Modules linked in: CR2: 0000000000000170 ---[ end trace 5d28f926b7ebfd06 ]--- RIP: 0010:arch_atomic_add_return arch/x86/include/asm/atomic.h:165 [inline] RIP: 0010:arch_atomic_inc_return include/linux/atomic-arch-fallback.h:286 [inline] RIP: 0010:atomic_inc_return include/asm-generic/atomic-instrumented.h:251 [inline] RIP: 0010:ihold+0x26/0x60 fs/inode.c:423 Code: 00 00 00 00 55 48 89 e5 41 56 53 48 89 fb e8 e1 65 b7 ff 48 8d bb 70 01 00 00 be 04 00 00 00 e8 00 e9 f1 ff 41 be 01 00 00 00 44 0f c1 b3 70 01 00 00 41 ff c6 bf 02 00 00 00 44 89 f6 e8 61 RSP: 0018:ffffc900013ef848 EFLAGS: 00010202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000286 RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000170 RBP: ffffc900013ef858 R08: 0000000000000000 R09: 1ffff11023914471 R10: dffffc0000000000 R11: ffffed1023914472 R12: 1ffff110260c9916 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000170 CR3: 000000000640f000 CR4: 00000000003506a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 00 00 add %al,(%rax) 4: 55 push %rbp 5: 48 89 e5 mov %rsp,%rbp 8: 41 56 push %r14 a: 53 push %rbx b: 48 89 fb mov %rdi,%rbx e: e8 e1 65 b7 ff call 0xffb765f4 13: 48 8d bb 70 01 00 00 lea 0x170(%rbx),%rdi 1a: be 04 00 00 00 mov $0x4,%esi 1f: e8 00 e9 f1 ff call 0xfff1e924 24: 41 be 01 00 00 00 mov $0x1,%r14d * 2a: f0 44 0f c1 b3 70 01 lock xadd %r14d,0x170(%rbx) <-- trapping instruction 31: 00 00 33: 41 ff c6 inc %r14d 36: bf 02 00 00 00 mov $0x2,%edi 3b: 44 89 f6 mov %r14d,%esi 3e: e8 .byte 0xe8 3f: 61 (bad)