bisecting fixing commit since 13d2ce42de8cb98ff952f8de6307f896203854c2 building syzkaller on 821e0b09046a2f972ace26fbdc02aef1116792d4 testing commit 13d2ce42de8cb98ff952f8de6307f896203854c2 with gcc (GCC) 8.4.1 20210217 kernel signature: db2c92c0b9abda5ebdd538b736dcbfa24e1f3c2ab0c30cf293d13376997f269e run #0: crashed: BUG: corrupted list in kobject_add_internal run #1: crashed: BUG: corrupted list in kobject_add_internal run #2: crashed: BUG: corrupted list in kobject_add_internal run #3: crashed: BUG: corrupted list in kobject_add_internal run #4: crashed: BUG: corrupted list in kobject_add_internal run #5: crashed: BUG: corrupted list in kobject_add_internal run #6: crashed: BUG: corrupted list in kobject_add_internal run #7: crashed: BUG: corrupted list in kobject_add_internal run #8: crashed: BUG: corrupted list in kobject_add_internal run #9: crashed: BUG: corrupted list in kobject_add_internal run #10: crashed: BUG: corrupted list in kobject_add_internal run #11: crashed: BUG: corrupted list in kobject_add_internal run #12: crashed: BUG: corrupted list in kobject_add_internal run #13: crashed: BUG: corrupted list in kobject_add_internal run #14: crashed: BUG: corrupted list in kobject_add_internal run #15: crashed: BUG: corrupted list in kobject_add_internal run #16: crashed: BUG: corrupted list in kobject_add_internal run #17: crashed: BUG: corrupted list in kobject_add_internal run #18: crashed: BUG: corrupted list in kobject_add_internal run #19: crashed: general protection fault in klist_next testing current HEAD 2034d6f0838e465dd8f120c4e946d8444b4bb5df testing commit 2034d6f0838e465dd8f120c4e946d8444b4bb5df with gcc (GCC) 8.4.1 20210217 kernel signature: 1be52d4bc16a25116d3917deb557664b95f5aae762e3d51be5e87a1c18efee69 run #0: crashed: BUG: corrupted list in kobject_add_internal run #1: crashed: BUG: corrupted list in kobject_add_internal run #2: crashed: BUG: corrupted list in kobject_add_internal run #3: crashed: BUG: corrupted list in kobject_add_internal run #4: crashed: BUG: corrupted list in kobject_add_internal run #5: crashed: BUG: corrupted list in kobject_add_internal run #6: crashed: BUG: corrupted list in kobject_add_internal run #7: crashed: BUG: corrupted list in kobject_add_internal run #8: crashed: general protection fault in klist_next run #9: crashed: general protection fault in klist_next revisions tested: 2, total time: 33m57.62190586s (build: 15m24.392410295s, test: 18m2.789028537s) the crash still happens on HEAD commit msg: Linux 4.19.184 crash: general protection fault in klist_next ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 kobject_add_internal failed for hci5:0 with -EEXIST, don't try to register things with the same name in the same directory. Bluetooth: hci5: failed to register connection device kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 8474 Comm: syz-executor.2 Not tainted 4.19.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:klist_next+0x48/0x450 lib/klist.c:378 Code: 48 89 fb 48 83 ec 18 80 3c 02 00 0f 85 e1 02 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 23 49 8d 7c 24 50 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 b4 02 00 00 4c 8d 6b 08 4d 8b 7c 24 50 48 b8 00 RSP: 0018:ffff888092a6f698 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: ffff888092a6f718 RCX: 0000000000000000 RDX: 000000000000000a RSI: ffff888092a6f718 RDI: 0000000000000050 RBP: ffff888092a6f6d8 R08: ffff888090f72990 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff86d84280 R15: dffffc0000000000 FS: 0000000001ad7400(0000) GS:ffff8880ba200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005595febe2270 CR3: 00000000a4726000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: next_device drivers/base/core.c:2397 [inline] device_find_child+0xb1/0x170 drivers/base/core.c:2540 hci_conn_del_sysfs+0xaa/0x150 net/bluetooth/hci_sysfs.c:71 hci_conn_cleanup+0x1ff/0x4e0 net/bluetooth/hci_conn.c:128 hci_conn_del+0x22c/0x6b0 net/bluetooth/hci_conn.c:611 hci_conn_hash_flush+0x171/0x230 net/bluetooth/hci_conn.c:1513 hci_dev_do_close+0x57e/0xe10 net/bluetooth/hci_core.c:1668 hci_unregister_dev+0x167/0x890 net/bluetooth/hci_core.c:3273 vhci_release+0x6b/0xe0 drivers/bluetooth/hci_vhci.c:354 __fput+0x249/0x7f0 fs/file_table.c:278 ____fput+0x9/0x10 fs/file_table.c:309 task_work_run+0x108/0x180 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xa6a/0x2d90 kernel/exit.c:870 do_group_exit+0xf8/0x2c0 kernel/exit.c:967 get_signal+0x30b/0x1970 kernel/signal.c:2589 do_signal+0x87/0x1870 arch/x86/kernel/signal.c:799 exit_to_usermode_loop+0x159/0x1e0 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x418d7c Code: Bad RIP value. RSP: 002b:00007fffa84e3f50 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: fffffffffffffe00 RBX: 00007fffa84e3ff0 RCX: 0000000000418d7c RDX: 0000000000000050 RSI: 0000000000568020 RDI: 00000000000000f9 RBP: 0000000000000003 R08: 0000000000000000 R09: 0079746972756365 R10: 00007fffa84e3910 R11: 0000000000000246 R12: 0000000000000032 R13: 0000000000000000 R14: 0000000000000003 R15: 00007fffa84e4030 Modules linked in: ---[ end trace eb179032c444eb13 ]--- RIP: 0010:klist_next+0x48/0x450 lib/klist.c:378 Code: 48 89 fb 48 83 ec 18 80 3c 02 00 0f 85 e1 02 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 23 49 8d 7c 24 50 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 b4 02 00 00 4c 8d 6b 08 4d 8b 7c 24 50 48 b8 00 RSP: 0018:ffff888092a6f698 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: ffff888092a6f718 RCX: 0000000000000000 RDX: 000000000000000a RSI: ffff888092a6f718 RDI: 0000000000000050 RBP: ffff888092a6f6d8 R08: ffff888090f72990 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff86d84280 R15: dffffc0000000000 FS: 0000000001ad7400(0000) GS:ffff8880ba200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f87efaf1810 CR3: 00000000a8402000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400