bisecting fixing commit since 75caf310d16cc5e2f851c048cd597f5437013368
building syzkaller on 3905eaae004605f4ec4dab83e6883173796118c8
testing commit 75caf310d16cc5e2f851c048cd597f5437013368 with gcc (GCC) 8.1.0
kernel signature: 5fbf152d677936aab32dd3a9228d8799d01b5bd2bcc067710b525741db4b01e2
all runs: crashed: WARNING in media_create_pad_link
testing current HEAD fffe3ae0ee84e25d2befe2ae59bc32aa2b6bc77b
testing commit fffe3ae0ee84e25d2befe2ae59bc32aa2b6bc77b with gcc (GCC) 8.1.0
kernel signature: 986bbfb5e663869181d412547c0d94efe662f488ef17cbd0bd72250c7cc4b014
all runs: crashed: WARNING in media_create_pad_link
revisions tested: 2, total time: 17m37.280610169s (build: 10m32.523685934s, test: 6m30.870883931s)
the crash still happens on HEAD
commit msg: Merge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
crash: WARNING in media_create_pad_link
uvcvideo 2-1:0.0: Entity type for entity Output 1 was not initialized!
------------[ cut here ]------------
WARNING: CPU: 1 PID: 3122 at drivers/media/mc/mc-entity.c:666 media_create_pad_link+0x131/0x170 drivers/media/mc/mc-entity.c:668
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 3122 Comm: kworker/1:3 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xb3/0xec lib/dump_stack.c:118
 panic+0x115/0x2fa kernel/panic.c:231
 __warn.cold.13+0x20/0x25 kernel/panic.c:600
 report_bug+0xc0/0xf0 lib/bug.c:198
 handle_bug+0x35/0x90 arch/x86/kernel/traps.c:235
 exc_invalid_op+0x13/0x60 arch/x86/kernel/traps.c:255
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536
RIP: 0010:media_create_pad_link+0x131/0x170 drivers/media/mc/mc-entity.c:666
Code: 89 7e 40 66 83 43 3c 01 66 83 43 3a 01 66 83 45 3a 01 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f c3 0f 0b b8 ea ff ff ff eb e8 <0f> 0b b8 ea ff ff ff eb df 0f 0b b8 ea ff ff ff eb d6 0f 0b b8 ea
RSP: 0018:ffffc9000601b838 EFLAGS: 00010297
RAX: ffff88810ffd6c00 RBX: ffff88810ffecc00 RCX: 0000000000000000
RDX: ffff88810ffecc70 RSI: 0000000000000001 RDI: ffff88810ffd6c70
RBP: ffff88810ffd7f18 R08: 0000000000000003 R09: ffffffff859ed598
R10: ffffffff846b7238 R11: 04d15bc3c3134305 R12: ffff88810ffd7f00
R13: ffff88810ffecc70 R14: 0000000000000000 R15: 0000000000000000
 uvc_mc_create_links drivers/media/usb/uvc/uvc_entity.c:50 [inline]
 uvc_mc_register_entities+0x161/0x1f0 drivers/media/usb/uvc/uvc_entity.c:114
 uvc_register_chains drivers/media/usb/uvc/uvc_driver.c:2103 [inline]
 uvc_probe.cold.21+0x9ed/0xc65 drivers/media/usb/uvc/uvc_driver.c:2229
 usb_probe_interface+0xde/0x210 drivers/usb/core/driver.c:374
 really_probe+0x29e/0x2e0 drivers/base/dd.c:557
 driver_probe_device+0x49/0xa0 drivers/base/dd.c:738
 bus_for_each_drv+0x74/0xc0 drivers/base/bus.c:431
 __device_attach+0xdd/0x140 drivers/base/dd.c:912
 bus_probe_device+0x94/0xb0 drivers/base/bus.c:491
 device_add+0x40a/0x780 drivers/base/core.c:2930
 usb_set_configuration+0x5c0/0x850 drivers/usb/core/message.c:2032
 usb_generic_driver_probe+0x34/0x60 drivers/usb/core/generic.c:239
 usb_probe_device+0x27/0x80 drivers/usb/core/driver.c:272
 really_probe+0x29e/0x2e0 drivers/base/dd.c:557
 driver_probe_device+0x49/0xa0 drivers/base/dd.c:738
 bus_for_each_drv+0x74/0xc0 drivers/base/bus.c:431
 __device_attach+0xdd/0x140 drivers/base/dd.c:912
 bus_probe_device+0x94/0xb0 drivers/base/bus.c:491
 device_add+0x40a/0x780 drivers/base/core.c:2930
 usb_new_device.cold.67+0x111/0x3d5 drivers/usb/core/hub.c:2554
 hub_port_connect drivers/usb/core/hub.c:5208 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5348 [inline]
 port_event drivers/usb/core/hub.c:5494 [inline]
 hub_event+0xb76/0x1280 drivers/usb/core/hub.c:5576
 process_one_work+0x26a/0x5f0 kernel/workqueue.c:2269
 worker_thread+0x38/0x380 kernel/workqueue.c:2415
 kthread+0x148/0x170 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Kernel Offset: disabled
Rebooting in 86400 seconds..