bisecting fixing commit since 13af6c74b14a883366e7702c40c52ff548096e7f building syzkaller on 02034dac31a9c4dfecfa163f445ef1921c442268 testing commit 13af6c74b14a883366e7702c40c52ff548096e7f with gcc (GCC) 8.1.0 kernel signature: ae5751a64026a27570c8cbf87a5ad7ac45a6c807748b4a9db8e885037b4c43f1 run #0: crashed: KASAN: use-after-free Read in __queue_work run #1: crashed: KASAN: use-after-free Read in __queue_work run #2: crashed: general protection fault in corrupted run #3: crashed: KASAN: use-after-free Read in __queue_work run #4: crashed: KASAN: use-after-free Read in __queue_work run #5: crashed: KASAN: use-after-free Read in l2cap_chan_del run #6: crashed: KASAN: use-after-free Read in __queue_work run #7: crashed: KASAN: use-after-free Read in __queue_work run #8: crashed: KASAN: use-after-free Read in __queue_work run #9: crashed: general protection fault in corrupted testing current HEAD 13d2ce42de8cb98ff952f8de6307f896203854c2 testing commit 13d2ce42de8cb98ff952f8de6307f896203854c2 with gcc (GCC) 8.1.0 kernel signature: ff9bdabbb386586fafd62aee2ef0f57dd94b9ea9ddb6a87e785beccae21696a3 run #0: crashed: KASAN: use-after-free Read in __queue_work run #1: crashed: KASAN: use-after-free Read in __queue_work run #2: crashed: KASAN: use-after-free Read in __queue_work run #3: crashed: KASAN: use-after-free Read in __queue_work run #4: crashed: KASAN: use-after-free Read in __queue_work run #5: crashed: KASAN: use-after-free Read in __queue_work run #6: crashed: KASAN: use-after-free Read in __queue_work run #7: crashed: KASAN: use-after-free Read in __queue_work run #8: crashed: KASAN: use-after-free Read in __queue_work run #9: crashed: general protection fault in corrupted revisions tested: 2, total time: 25m14.794305303s (build: 17m53.258278765s, test: 6m32.246306504s) the crash still happens on HEAD commit msg: Linux 4.19.163 crash: general protection fault in corrupted Bluetooth: hci1: command 0x0405 tx timeout Bluetooth: hci1: command 0x0405 tx timeout 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 BUG: KASAN: use-after-free in __queue_work+0xa2e/0xdf0 kernel/workqueue.c:1383 CPU: 1 PID: 7139 Comm: kworker/1:5 Not tainted 4.19.163-syzkaller #0 Read of size 4 at addr ffff8881d8e736c0 by task kworker/0:1/14 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 CPU: 0 PID: 14 Comm: kworker/0:1 Not tainted 4.19.163-syzkaller #0 Workqueue: events l2cap_chan_timeout Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__queue_work+0x400/0xdf0 kernel/workqueue.c:1404 Workqueue: events l2cap_chan_timeout Code: 80 3c 3a 00 0f 85 b7 08 00 00 48 89 df 4c 03 34 c5 00 6f 2b 88 e8 50 da ff ff 48 85 c0 0f 85 63 fd ff ff 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 0f 85 81 09 00 00 49 8b 06 e9 64 fd ff ff 65 8b 05 Call Trace: RSP: 0018:ffff8881dc00fb08 EFLAGS: 00010046 __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x17c/0x22a lib/dump_stack.c:118 RAX: 0000000000000000 RBX: ffff8881d576e560 RCX: ffffed103ea745d0 print_address_description.cold.6+0x9/0x211 mm/kasan/report.c:256 RDX: 1ffffffff10a3f50 RSI: 0000000000000000 RDI: ffffffff8851fa80 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x307 mm/kasan/report.c:412 RBP: ffff8881dc00fb78 R08: 1ffff1103ea745d0 R09: ffffed103ed2473a R10: ffffed103ed2473a R11: ffff8881f69239d3 R12: ffff8881da1ee300 R13: 0000000000000001 R14: 0000000000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f294e1ad000 CR3: 000000000846d001 CR4: 00000000001606e0 __queue_work+0xa2e/0xdf0 kernel/workqueue.c:1383 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __queue_delayed_work+0x174/0x290 kernel/workqueue.c:1524 __queue_delayed_work+0x174/0x290 kernel/workqueue.c:1524 queue_delayed_work_on+0x148/0x180 kernel/workqueue.c:1560 queue_delayed_work include/linux/workqueue.h:527 [inline] hci_conn_drop include/net/bluetooth/hci_core.h:998 [inline] l2cap_chan_del+0x45b/0x7b0 net/bluetooth/l2cap_core.c:616 queue_delayed_work_on+0x148/0x180 kernel/workqueue.c:1560 l2cap_chan_close+0x35b/0x830 net/bluetooth/l2cap_core.c:757 queue_delayed_work include/linux/workqueue.h:527 [inline] hci_conn_drop include/net/bluetooth/hci_core.h:998 [inline] l2cap_chan_del+0x45b/0x7b0 net/bluetooth/l2cap_core.c:616 l2cap_chan_close+0x35b/0x830 net/bluetooth/l2cap_core.c:757 l2cap_chan_timeout+0x11d/0x1c0 net/bluetooth/l2cap_core.c:430 l2cap_chan_timeout+0x11d/0x1c0 net/bluetooth/l2cap_core.c:430 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2155 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2155 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 kthread+0x347/0x410 kernel/kthread.c:259 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Modules linked in: Allocated by task 2861: ---[ end trace 8dab65b783826e13 ]--- save_stack mm/kasan/kasan.c:448 [inline] set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc.part.1+0x62/0xf0 mm/kasan/kasan.c:553 RIP: 0010:__queue_work+0x400/0xdf0 kernel/workqueue.c:1404 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:538 Code: 80 3c 3a 00 0f 85 b7 08 00 00 48 89 df 4c 03 34 c5 00 6f 2b 88 e8 50 da ff ff 48 85 c0 0f 85 63 fd ff ff 4c 89 f0 48 c1 e8 03 <42> 80 3c 38 00 0f 85 81 09 00 00 49 8b 06 e9 64 fd ff ff 65 8b 05 __do_kmalloc mm/slab.c:3727 [inline] __kmalloc+0x15d/0x3d0 mm/slab.c:3736 RSP: 0018:ffff8881dc00fb08 EFLAGS: 00010046 kmalloc include/linux/slab.h:520 [inline] kzalloc include/linux/slab.h:709 [inline] __alloc_workqueue_key+0x5b9/0xbb0 kernel/workqueue.c:4087 RAX: 0000000000000000 RBX: ffff8881d576e560 RCX: ffffed103ea745d0 RDX: 1ffffffff10a3f50 RSI: 0000000000000000 RDI: ffffffff8851fa80 hci_register_dev+0x185/0x750 net/bluetooth/hci_core.c:3179 RBP: ffff8881dc00fb78 R08: 1ffff1103ea745d0 R09: ffffed103ed2473a __vhci_create_device+0x269/0x4f0 drivers/bluetooth/hci_vhci.c:139 R10: ffffed103ed2473a R11: ffff8881f69239d3 R12: ffff8881da1ee300 vhci_create_device drivers/bluetooth/hci_vhci.c:163 [inline] vhci_open_timeout+0x34/0x50 drivers/bluetooth/hci_vhci.c:319 R13: 0000000000000001 R14: 0000000000000000 R15: dffffc0000000000 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2155 FS: 0000000000000000(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 kthread+0x347/0x410 kernel/kthread.c:259 CR2: 00007f294e1ad000 CR3: 000000000846d001 CR4: 00000000001606e0 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Freed by task 0: