bisecting fixing commit since 449dc8c97089a6e09fb2dac4d92b1b7ac0eb7c1e
building syzkaller on f721e4a097714a9054b9fe1aadf427afbbd2c157
testing commit 449dc8c97089a6e09fb2dac4d92b1b7ac0eb7c1e with gcc (GCC) 8.1.0
kernel signature: 5684b8602e3bb43948bfa6067b78da1e419173cf109c937b5973f27595f41cfb
all runs: crashed: WARNING: refcount bug in l2cap_global_chan_by_psm
testing current HEAD 82821be8a2e14bdf359be577400be88b2f1eb8a7
testing commit 82821be8a2e14bdf359be577400be88b2f1eb8a7 with gcc (GCC) 8.1.0
kernel signature: 3cab448f29bab05de451b30a71a9fa6af7c57e99d080542ec8c552d7268b80bc
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: crashed: WARNING: refcount bug in l2cap_global_chan_by_psm
run #3: crashed: WARNING: refcount bug in l2cap_global_chan_by_psm
run #4: crashed: WARNING: refcount bug in l2cap_global_chan_by_psm
run #5: crashed: WARNING: refcount bug in l2cap_global_chan_by_psm
run #6: crashed: WARNING: refcount bug in l2cap_global_chan_by_psm
run #7: crashed: WARNING: refcount bug in l2cap_global_chan_by_psm
run #8: crashed: WARNING: refcount bug in l2cap_global_chan_by_psm
run #9: crashed: WARNING: refcount bug in l2cap_global_chan_by_psm
revisions tested: 2, total time: 22m26.11713187s (build: 9m56.2587755s, test: 11m43.324345624s)
the crash still happens on HEAD
commit msg: Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
crash: WARNING: refcount bug in l2cap_global_chan_by_psm
------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 13771 at lib/refcount.c:25 refcount_warn_saturate+0x80/0xe0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 13771 Comm: kworker/u5:0 Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci0 hci_rx_work
RIP: 0010:refcount_warn_saturate+0x80/0xe0 lib/refcount.c:25
Code: 05 ba 76 bf 02 01 e8 43 62 34 01 0f 0b c3 80 3d aa 76 bf 02 00 75 b8 48 c7 c7 f0 e4 f7 83 c6 05 9a 76 bf 02 01 e8 24 62 34 01 <0f> 0b c3 80 3d 8d 76 bf 02 00 75 99 48 c7 c7 c8 e4 f7 83 c6 05 7d
RSP: 0018:ffffc90000d33cc8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000080000002 RSI: ffffffff84087901 RDI: 00000000ffffffff
RBP: ffff8881136fe000 R08: 0000000000000001 R09: 0000000000000001
R10: ffffc90000d33af8 R11: ffffc90000d33af0 R12: 0000000000000000
R13: 0000000000000001 R14: ffffffff84851148 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff3413cb04 CR3: 00000001043e7000 CR4: 0000000000350ef0
Call Trace:
 __refcount_add include/linux/refcount.h:199 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 kref_get include/linux/kref.h:45 [inline]
 l2cap_chan_hold net/bluetooth/l2cap_core.c:495 [inline]
 l2cap_global_chan_by_psm+0x1f8/0x220 net/bluetooth/l2cap_core.c:1984
 l2cap_conless_channel net/bluetooth/l2cap_core.c:7602 [inline]
 l2cap_recv_frame+0x554/0x2e40 net/bluetooth/l2cap_core.c:7672
 hci_acldata_packet net/bluetooth/hci_core.c:4785 [inline]
 hci_rx_work+0x1d3/0x500 net/bluetooth/hci_core.c:4976
 process_one_work+0x293/0x600 kernel/workqueue.c:2275
 worker_thread+0x38/0x380 kernel/workqueue.c:2421
 kthread+0x145/0x170 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296