bisecting fixing commit since 13af6c74b14a883366e7702c40c52ff548096e7f building syzkaller on 02034dac31a9c4dfecfa163f445ef1921c442268 testing commit 13af6c74b14a883366e7702c40c52ff548096e7f with gcc (GCC) 8.1.0 kernel signature: 1fc5e9e8c4fe1be1aa95bb02a4d4c1b71e597427ee0e849e6d4238c0f61f670b 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 in __queue_work run #3: crashed: KASAN: use-after-free Read in __queue_work run #4: crashed: general protection fault in corrupted run #5: crashed: general protection fault in corrupted run #6: crashed: KASAN: use-after-free Read in __queue_work run #7: crashed: KASAN: use-after-free in __queue_work run #8: crashed: KASAN: use-after-free Read in __queue_work run #9: crashed: KASAN: use-after-free Read in __queue_work testing current HEAD 2c746135a12e3f329171ed168ca0078d468f6d85 testing commit 2c746135a12e3f329171ed168ca0078d468f6d85 with gcc (GCC) 8.1.0 kernel signature: cd8da6d766f0f64f021a41a18eaf3f6422d67007bd941b36a98dab3b0abc1a3a 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 in __queue_work run #5: crashed: KASAN: use-after-free Read in __queue_work run #6: crashed: general protection fault in corrupted run #7: crashed: general protection fault in corrupted run #8: crashed: KASAN: use-after-free Read in __queue_work run #9: crashed: general protection fault in corrupted revisions tested: 2, total time: 24m35.143488687s (build: 17m1.290300821s, test: 6m44.562872244s) the crash still happens on HEAD commit msg: Linux 4.19.158 crash: general protection fault in corrupted IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready Bluetooth: hci5: 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: 0 PID: 14 Comm: kworker/0:1 Not tainted 4.19.158-syzkaller #0 Read of size 4 at addr ffff8880a4f3be00 by task kworker/1:2/3408 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events l2cap_chan_timeout CPU: 1 PID: 3408 Comm: kworker/1:2 Not tainted 4.19.158-syzkaller #0 RIP: 0010:__queue_work+0x400/0xdf0 kernel/workqueue.c:1404 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Code: 80 3c 3a 00 0f 85 b7 08 00 00 48 89 df 4c 03 34 c5 00 5f 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 Workqueue: events l2cap_chan_timeout RSP: 0018:ffff8880b5befb08 EFLAGS: 00010046 Call Trace: RAX: 0000000000000000 RBX: ffff8880a3882c20 RCX: ffffed1016b7ad80 __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x17c/0x22a lib/dump_stack.c:118 RDX: 1ffffffff10a3f40 RSI: 0000000000000000 RDI: ffffffff8851fa00 print_address_description.cold.6+0x9/0x211 mm/kasan/report.c:256 RBP: ffff8880b5befb78 R08: 1ffff11016b7ad80 R09: ffffed10174c473a kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x307 mm/kasan/report.c:412 R10: ffffed10174c473a R11: ffff8880ba6239d3 R12: ffff8880a6726780 R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 FS: 0000000000000000(0000) GS:ffff8880ba600000(0000) knlGS:0000000000000000 __queue_work+0xa2e/0xdf0 kernel/workqueue.c:1383 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffff152ff78 CR3: 00000000b01ec000 CR4: 00000000001406f0 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_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 l2cap_chan_close+0x35b/0x830 net/bluetooth/l2cap_core.c:757 __queue_delayed_work+0x174/0x290 kernel/workqueue.c:1524 l2cap_chan_timeout+0x11d/0x1c0 net/bluetooth/l2cap_core.c:430 queue_delayed_work_on+0x148/0x180 kernel/workqueue.c:1560 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2155 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 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2155 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 kthread+0x347/0x410 kernel/kthread.c:259 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 kthread+0x347/0x410 kernel/kthread.c:259 Allocated by task 14: 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 kasan_kmalloc+0xaf/0xc0 mm/kasan/kasan.c:538 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 __do_kmalloc mm/slab.c:3727 [inline] __kmalloc+0x15d/0x3d0 mm/slab.c:3736 Modules linked in: kmalloc include/linux/slab.h:520 [inline] kzalloc include/linux/slab.h:709 [inline] __alloc_workqueue_key+0x5b9/0xbb0 kernel/workqueue.c:4087 ---[ end trace 15b01b1a6de21335 ]--- hci_register_dev+0x185/0x750 net/bluetooth/hci_core.c:3179 RIP: 0010:__queue_work+0x400/0xdf0 kernel/workqueue.c:1404 __vhci_create_device+0x269/0x4f0 drivers/bluetooth/hci_vhci.c:139 Code: 80 3c 3a 00 0f 85 b7 08 00 00 48 89 df 4c 03 34 c5 00 5f 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 vhci_create_device drivers/bluetooth/hci_vhci.c:163 [inline] vhci_open_timeout+0x34/0x50 drivers/bluetooth/hci_vhci.c:319 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2155 RSP: 0018:ffff8880b5befb08 EFLAGS: 00010046 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 RAX: 0000000000000000 RBX: ffff8880a3882c20 RCX: ffffed1016b7ad80 kthread+0x347/0x410 kernel/kthread.c:259 RDX: 1ffffffff10a3f40 RSI: 0000000000000000 RDI: ffffffff8851fa00 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 RBP: ffff8880b5befb78 R08: 1ffff11016b7ad80 R09: ffffed10174c473a R10: ffffed10174c473a R11: ffff8880ba6239d3 R12: ffff8880a6726780 Freed by task 3715: R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000 save_stack mm/kasan/kasan.c:448 [inline] set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x13c/0x220 mm/kasan/kasan.c:521 FS: 0000000000000000(0000) GS:ffff8880ba600000(0000) knlGS:0000000000000000 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 __cache_free mm/slab.c:3503 [inline] kfree+0xcf/0x220 mm/slab.c:3822 CR2: 00007ffff152ff78 CR3: 00000000b01ec000 CR4: 00000000001406f0 rcu_free_wq+0x99/0xf0 kernel/workqueue.c:3339 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 __rcu_reclaim kernel/rcu/rcu.h:236 [inline] rcu_do_batch kernel/rcu/tree.c:2584 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2897 [inline] __rcu_process_callbacks kernel/rcu/tree.c:2864 [inline] rcu_process_callbacks+0x93a/0x19b0 kernel/rcu/tree.c:2881 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 __do_softirq+0x25e/0x92d kernel/softirq.c:292