bisecting fixing commit since 357668399cf70ccdc0ee8967bff3448d0f4f9ae1 building syzkaller on 5d7b90f1af2e3bf33992b75e7fcf0bab6bf49bd6 testing commit 357668399cf70ccdc0ee8967bff3448d0f4f9ae1 with gcc (GCC) 8.1.0 kernel signature: fc2308c9ad29efc62e36d7bc42c59773f3247fc39f784eb1c15842ec99627919 all runs: crashed: WARNING: ODEBUG bug in rfcomm_dlc_free testing current HEAD 5692097116094a4a7045abcc1dbc172dbdc5657e testing commit 5692097116094a4a7045abcc1dbc172dbdc5657e with gcc (GCC) 8.1.0 kernel signature: 25b5f66109a3ceac9acf557e073bcdbd57e35e31a2c7e2f1f34d2b9d74963e5d all runs: crashed: WARNING: ODEBUG bug in rfcomm_dlc_free revisions tested: 2, total time: 27m51.372531076s (build: 19m26.265666175s, test: 7m24.674391759s) the crash still happens on HEAD commit msg: Linux 4.19.109 crash: WARNING: ODEBUG bug in rfcomm_dlc_free audit: type=1400 audit(1584259884.480:42): avc: denied { associate } for pid=7234 comm="syz-executor.0" name="syz0" scontext=unconfined_u:object_r:unlabeled_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=filesystem permissive=1 ------------[ cut here ]------------ ODEBUG: free active (active state 0) object type: timer_list hint: rfcomm_dlc_timeout+0x0/0x50 net/bluetooth/rfcomm/core.c:705 WARNING: CPU: 0 PID: 7432 at lib/debugobjects.c:328 debug_print_object+0x168/0x210 lib/debugobjects.c:325 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 7432 Comm: syz-executor.3 Not tainted 4.19.109-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 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1037 RIP: 0010:debug_print_object+0x168/0x210 lib/debugobjects.c:325 Code: 67 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 92 00 00 00 48 8b 14 dd 00 8c 67 87 4c 89 fe 48 c7 c7 40 81 67 87 e8 db 05 0b fe <0f> 0b 83 05 6b 01 f5 05 01 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffff88808b677828 EFLAGS: 00010082 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000 RDX: 0000000000000004 RSI: 0000000000000008 RDI: ffffffff8a183960 RBP: ffff88808b677868 R08: ffffed1015d43ee3 R09: ffffed1015d43ee2 R10: ffffed1015d43ee2 R11: ffff8880aea1f717 R12: 0000000000000001 R13: ffffffff88599700 R14: ffffffff8152fea0 R15: ffffffff87678820 __debug_check_no_obj_freed lib/debugobjects.c:785 [inline] debug_check_no_obj_freed+0x264/0x472 lib/debugobjects.c:817 kfree+0xbd/0x220 mm/slab.c:3821 rfcomm_dlc_free+0x19/0x20 net/bluetooth/rfcomm/core.c:328 rfcomm_dlc_put include/net/bluetooth/rfcomm.h:258 [inline] __rfcomm_create_dev net/bluetooth/rfcomm/tty.c:417 [inline] rfcomm_create_dev net/bluetooth/rfcomm/tty.c:486 [inline] rfcomm_dev_ioctl+0x14f3/0x1970 net/bluetooth/rfcomm/tty.c:588 rfcomm_sock_ioctl+0x71/0xa0 net/bluetooth/rfcomm/sock.c:902 sock_do_ioctl+0xd9/0x230 net/socket.c:950 sock_ioctl+0x281/0x500 net/socket.c:1074 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688 ksys_ioctl+0x62/0x90 fs/ioctl.c:705 __do_sys_ioctl fs/ioctl.c:712 [inline] __se_sys_ioctl fs/ioctl.c:710 [inline] __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c6c9 Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f7dd5238c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f7dd52396d4 RCX: 000000000045c6c9 RDX: 0000000020000100 RSI: 00000000400452c8 RDI: 0000000000000006 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000312 R14: 00000000004c5631 R15: 000000000076bf2c ======================================================