bisecting fixing commit since 830a059cbba6832c11fefc0894c7ec7a27f75734 building syzkaller on 6a81331a1d4c744da9204d02ec88d558f7eea9c9 testing commit 830a059cbba6832c11fefc0894c7ec7a27f75734 with gcc (GCC) 8.4.1 20210217 kernel signature: 9b9a53916662a9dc927952aa1e87fa912320cfdbb2b25534e8ed2e8b2bf082dc run #0: crashed: general protection fault in klist_iter_exit run #1: crashed: general protection fault in klist_iter_exit run #2: crashed: general protection fault in klist_iter_exit run #3: crashed: general protection fault in klist_iter_exit run #4: crashed: general protection fault in klist_iter_exit run #5: crashed: general protection fault in klist_iter_exit run #6: crashed: general protection fault in klist_iter_exit run #7: crashed: general protection fault in klist_iter_exit run #8: crashed: general protection fault in klist_iter_exit run #9: crashed: general protection fault in klist_iter_exit run #10: crashed: general protection fault in klist_iter_exit run #11: crashed: general protection fault in klist_iter_exit run #12: crashed: general protection fault in corrupted run #13: crashed: general protection fault in klist_iter_exit run #14: crashed: general protection fault in klist_iter_exit run #15: crashed: general protection fault in klist_iter_exit run #16: crashed: general protection fault in corrupted run #17: crashed: general protection fault in corrupted run #18: crashed: general protection fault in klist_iter_exit run #19: crashed: general protection fault in klist_iter_exit testing current HEAD 1722257b8ececec9b3b83a8b14058f8209d78071 testing commit 1722257b8ececec9b3b83a8b14058f8209d78071 with gcc (GCC) 8.4.1 20210217 kernel signature: cd493fbb35c8b5db7718a90824e1383ce4570668ca956c5886cc8c46538537c8 all runs: crashed: general protection fault in klist_iter_exit revisions tested: 2, total time: 30m5.43695359s (build: 22m46.775061498s, test: 6m47.710725056s) the crash still happens on HEAD commit msg: Linux 4.19.193 crash: general protection fault in klist_iter_exit genl_family_rcv_msg+0x9cc/0x1000 net/netlink/genetlink.c:550 genl_rcv_msg+0xa7/0x140 net/netlink/genetlink.c:627 netlink_rcv_skb+0x13e/0x3d0 net/netlink/af_netlink.c:2455 genl_rcv+0x23/0x40 net/netlink/genetlink.c:638 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x443/0x660 net/netlink/af_netlink.c:1344 general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 1 PID: 19 Comm: kworker/1:0 Not tainted 4.19.193-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events netlink_sock_destruct_work netlink_sendmsg+0x667/0xc60 net/netlink/af_netlink.c:1909 RIP: 0010:klist_iter_exit+0x1f/0x70 lib/klist.c:314 Code: 00 48 89 e5 e8 e2 fe ff ff 5d c3 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 54 4c 8d 67 08 53 48 89 fb 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 75 34 48 8b 7b 08 48 85 ff 74 26 31 f6 e8 ab fe ff ff RSP: 0018:ffff8880b5a2fc28 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:632 RDX: 0000000000000001 RSI: 0000000000000008 RDI: 0000000000000000 ___sys_sendmsg+0x647/0x950 net/socket.c:2115 RBP: ffff8880b5a2fc38 R08: fffffbfff14faad5 R09: fffffbfff14faad4 R10: ffff8880b5a2fc60 R11: ffffffff8a7d56a7 R12: 0000000000000008 R13: ffffffff88fd6c20 R14: 0000000000000000 R15: ffff888096ff1bc8 FS: 0000000000000000(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000558b60ca34d8 CR3: 00000000b4506000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: class_dev_iter_exit+0x9/0x10 drivers/base/class.c:323 nfc_device_iter_exit net/nfc/nfc.h:133 [inline] nfc_genl_dump_devices_done+0x2f/0x50 net/nfc/netlink.c:658 genl_lock_done+0x7e/0xc0 net/netlink/genetlink.c:495 netlink_sock_destruct+0x7f/0x230 net/netlink/af_netlink.c:398 __sk_destruct+0x48/0x670 net/core/sock.c:1559 __sys_sendmsg+0xd9/0x180 net/socket.c:2153 sk_destruct+0x83/0xb0 net/core/sock.c:1599 __sk_free+0x9e/0x230 net/core/sock.c:1610 sk_free+0x1a/0x20 net/core/sock.c:1621 netlink_sock_destruct_work+0x10/0x20 net/netlink/af_netlink.c:420 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2152 __do_sys_sendmsg net/socket.c:2162 [inline] __se_sys_sendmsg net/socket.c:2160 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2160 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x466459 worker_thread+0x85/0xb60 kernel/workqueue.c:2295 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3f10201188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e kthread+0x347/0x410 kernel/kthread.c:259 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466459 RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000004 RBP: 00007f3f102011d0 R08: 0000000000000000 R09: 0000000000000000 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 Modules linked in: R13: 00007ffd06fc5d3f R14: 00007f3f10201300 R15: 0000000000022000 ---[ end trace 4c98c6671e7967b3 ]--- Bluetooth: hci3: command 0x0419 tx timeout CPU: 0 PID: 9956 Comm: syz-executor.3 Tainted: G D 4.19.193-syzkaller #0 RIP: 0010:klist_iter_exit+0x1f/0x70 lib/klist.c:314 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+0x17c/0x226 lib/dump_stack.c:118 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold.2+0x5/0xa lib/fault-inject.c:149 __should_failslab+0xba/0xf0 mm/failslab.c:32 should_failslab+0x9/0x20 mm/slab_common.c:1588 slab_pre_alloc_hook mm/slab.h:424 [inline] slab_alloc_node mm/slab.c:3304 [inline] kmem_cache_alloc_node_trace+0x256/0x3e0 mm/slab.c:3666 __do_kmalloc_node mm/slab.c:3688 [inline] __kmalloc_node_track_caller+0x3c/0x70 mm/slab.c:3703 __kmalloc_reserve.isra.9+0x2c/0xc0 net/core/skbuff.c:137 __alloc_skb+0xd7/0x580 net/core/skbuff.c:205 alloc_skb include/linux/skbuff.h:995 [inline] netlink_dump+0x4c2/0x9b0 net/netlink/af_netlink.c:2215 __netlink_dump_start+0x496/0x6c0 net/netlink/af_netlink.c:2330 genl_family_rcv_msg+0x9cc/0x1000 net/netlink/genetlink.c:550 Code: 00 48 89 e5 e8 e2 fe ff ff 5d c3 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 54 4c 8d 67 08 53 48 89 fb 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 75 34 48 8b 7b 08 48 85 ff 74 26 31 f6 e8 ab fe ff ff RSP: 0018:ffff8880b5a2fc28 EFLAGS: 00010202 genl_rcv_msg+0xa7/0x140 net/netlink/genetlink.c:627 netlink_rcv_skb+0x13e/0x3d0 net/netlink/af_netlink.c:2455 genl_rcv+0x23/0x40 net/netlink/genetlink.c:638 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x443/0x660 net/netlink/af_netlink.c:1344 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000008 RDI: 0000000000000000 netlink_sendmsg+0x667/0xc60 net/netlink/af_netlink.c:1909 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:632 ___sys_sendmsg+0x647/0x950 net/socket.c:2115 RBP: ffff8880b5a2fc38 R08: fffffbfff14faad5 R09: fffffbfff14faad4 R10: ffff8880b5a2fc60 R11: ffffffff8a7d56a7 R12: 0000000000000008 R13: ffffffff88fd6c20 R14: 0000000000000000 R15: ffff888096ff1bc8 __sys_sendmsg+0xd9/0x180 net/socket.c:2153 FS: 0000000000000000(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 __do_sys_sendmsg net/socket.c:2162 [inline] __se_sys_sendmsg net/socket.c:2160 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2160 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x466459 CR2: 00007fb538911000 CR3: 00000000a1874000 CR4: 00000000001406e0 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f7614597188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466459 RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000004 RBP: 00007f76145971d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffeee4b035f R14: 00007f7614597300 R15: 0000000000022000 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400