bisecting fixing commit since c0842fbc1b18c7a044e6ff3e8fa78bfa822c7d1a
building syzkaller on 80a0690249dc4dbbbed95ba197192b99c73694c5
testing commit c0842fbc1b18c7a044e6ff3e8fa78bfa822c7d1a with gcc (GCC) 8.1.0
kernel signature: c43ecf7aa6081f4899eb274c0fac101b708bd51f04bb268b832638af752bc1c1
run #0: boot failed: create image operation failed: &{Code:ZONE_RESOURCE_POOL_EXHAUSTED_WITH_DETAILS Location: Message:The zone 'projects/syzkaller/zones/us-central1-c' does not have enough resources available to fulfill the request.  '(resource type:compute)'. ForceSendFields:[] NullFields:[]}.
run #1: boot failed: create image operation failed: &{Code:ZONE_RESOURCE_POOL_EXHAUSTED_WITH_DETAILS Location: Message:The zone 'projects/syzkaller/zones/us-central1-c' does not have enough resources available to fulfill the request.  '(resource type:compute)'. ForceSendFields:[] NullFields:[]}.
run #2: boot failed: create image operation failed: &{Code:ZONE_RESOURCE_POOL_EXHAUSTED_WITH_DETAILS Location: Message:The zone 'projects/syzkaller/zones/us-central1-c' does not have enough resources available to fulfill the request.  '(resource type:compute)'. ForceSendFields:[] NullFields:[]}.
run #3: boot failed: create image operation failed: &{Code:ZONE_RESOURCE_POOL_EXHAUSTED_WITH_DETAILS Location: Message:The zone 'projects/syzkaller/zones/us-central1-c' does not have enough resources available to fulfill the request.  '(resource type:compute)'. ForceSendFields:[] NullFields:[]}.
run #4: crashed: WARNING: ODEBUG bug in bt_host_release
run #5: crashed: WARNING: ODEBUG bug in bt_host_release
run #6: OK
run #7: OK
run #8: OK
run #9: OK
reproducer seems to be flaky
testing current HEAD 45dfb8a5659ad286c28fa59008271dbc4e5e3f2d
testing commit 45dfb8a5659ad286c28fa59008271dbc4e5e3f2d with gcc (GCC) 8.1.0
kernel signature: b7a2361b78bdde84810a5076212e771b915b10189d3edaa88f669e9902ec13c9
run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in __queue_work
run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in __queue_work
run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in __queue_work
run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in __queue_work
run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in __queue_work
run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in __queue_work
run #6: crashed: BUG: unable to handle kernel NULL pointer dereference in __queue_work
run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in __queue_work
run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in __queue_work
run #9: OK
Reproducer flagged being flaky
revisions tested: 2, total time: 27m39.809437443s (build: 10m5.709643483s, test: 16m59.328476254s)
the crash still happens on HEAD
commit msg: Merge tag 'task_work-2021-01-19' of git://git.kernel.dk/linux-block
crash: BUG: unable to handle kernel NULL pointer dereference in __queue_work
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 109321067 P4D 109321067 PUD 10b73d067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP
CPU: 0 PID: 21700 Comm: syz-executor.2 Not tainted 5.11.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__queue_work+0xdc/0x670 kernel/workqueue.c:1440
Code: 88 03 00 00 44 89 ef e8 32 43 f1 ff 4c 89 e7 89 c6 e8 88 d3 ff ff 48 89 df 49 89 c7 e8 ed dd ff ff 48 85 c0 0f 84 2f 01 00 00 <49> 39 07 0f 85 75 02 00 00 48 89 c7 e8 33 f0 f3 01 41 8b 47 18 85
RSP: 0018:ffffc90000823c08 EFLAGS: 00010086
RAX: ffff88810095d400 RBX: ffff888112d14a88 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000005 RDI: ffffffff844f0640
RBP: ffffc90000823c40 R08: ffff888100400050 R09: ffff888100400000
R10: 0000000000000000 R11: ffffffff844f0688 R12: ffff888114f93000
R13: 0000000000000000 R14: 0000000000000040 R15: 0000000000000000
FS:  00007ff1fb748700(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000010d36f000 CR4: 0000000000350ef0
Call Trace:
 queue_work_on+0x99/0xb0 kernel/workqueue.c:1524
 queue_work include/linux/workqueue.h:507 [inline]
 req_run+0xa9/0xf0 net/bluetooth/hci_request.c:87
 hci_req_run_skb net/bluetooth/hci_request.c:99 [inline]
 __hci_req_sync+0xd9/0x280 net/bluetooth/hci_request.c:212
 hci_req_sync+0x49/0x70 net/bluetooth/hci_request.c:279
 hci_dev_cmd+0x1b2/0x2c0 net/bluetooth/hci_core.c:2026
 hci_sock_ioctl+0x1f6/0x3e0 net/bluetooth/hci_sock.c:1052
 sock_do_ioctl+0x38/0x130 net/socket.c:1037
 sock_ioctl+0x260/0x350 net/socket.c:1177
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x7c/0xb0 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cce9
Code: 2d 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ff1fb747c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000001d300 RCX: 000000000045cce9
RDX: 0000000020000000 RSI: 00000000400448de RDI: 0000000000000004
RBP: 000000000078c080 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078c04c
R13: 00007fffe2e3830f R14: 00007ff1fb7489c0 R15: 000000000078c04c
Modules linked in:
CR2: 0000000000000000
---[ end trace 8e83a36ef643f81c ]---
RIP: 0010:__queue_work+0xdc/0x670 kernel/workqueue.c:1440
Code: 88 03 00 00 44 89 ef e8 32 43 f1 ff 4c 89 e7 89 c6 e8 88 d3 ff ff 48 89 df 49 89 c7 e8 ed dd ff ff 48 85 c0 0f 84 2f 01 00 00 <49> 39 07 0f 85 75 02 00 00 48 89 c7 e8 33 f0 f3 01 41 8b 47 18 85
RSP: 0018:ffffc90000823c08 EFLAGS: 00010086
RAX: ffff88810095d400 RBX: ffff888112d14a88 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000005 RDI: ffffffff844f0640
RBP: ffffc90000823c40 R08: ffff888100400050 R09: ffff888100400000
R10: 0000000000000000 R11: ffffffff844f0688 R12: ffff888114f93000
R13: 0000000000000000 R14: 0000000000000040 R15: 0000000000000000
FS:  00007ff1fb748700(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000010d36f000 CR4: 0000000000350ef0