bisecting fixing commit since 521b619acdc8f1f5acdac15b84f81fd9515b2aff
building syzkaller on 64069d48f293e0be98d4a78a6f7be23861cc1e06
testing commit 521b619acdc8f1f5acdac15b84f81fd9515b2aff with gcc (GCC) 8.1.0
kernel signature: 3e2905ceb5145de4cf91cb98e751c1f3742dbe369bfbf00a84d5daca8f9ec11e
all runs: crashed: WARNING in pvr2_i2c_core_done
testing current HEAD 0477e92881850d44910a7e94fc2c46f96faa131f
testing commit 0477e92881850d44910a7e94fc2c46f96faa131f with gcc (GCC) 8.1.0
kernel signature: 7a808505d7c3fe4de9edb5143d395297f6890c1103f2c54299ba4a6d04a95f1e
all runs: crashed: WARNING in pvr2_i2c_core_done
revisions tested: 2, total time: 15m22.668213262s (build: 8m46.587774635s, test: 5m44.595825523s)
the crash still happens on HEAD
commit msg: Linux 5.10-rc7
crash: WARNING in pvr2_i2c_core_done
WARNING: CPU: 0 PID: 4044 at fs/sysfs/group.c:281 sysfs_remove_group+0x71/0x80 fs/sysfs/group.c:279
Modules linked in:

CPU: 0 PID: 4044 Comm: pvrusb2-context Not tainted 5.10.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:sysfs_remove_group+0x71/0x80 fs/sysfs/group.c:279
Code: 48 89 df 5b 5d 41 5c e9 ed b7 ff ff 48 89 df e8 c5 b7 ff ff eb cb 49 8b 14 24 48 c7 c7 00 49 6d 84 48 8b 75 00 e8 e0 78 f7 01 <0f> 0b 5b 5d 41 5c c3 0f 1f 84 00 00 00 00 00 48 85 f6 74 31 41 54
RSP: 0018:ffffc9000724fd88 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000080000001 RSI: ffffffff84926e36 RDI: 00000000ffffffff
RBP: ffffffff83e29120 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000002 R12: ffff88811ce6f820
R13: ffff88811f3ec998 R14: dead000000000122 R15: dead000000000100
FS:  0000000000000000(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fabd971fbf0 CR3: 000000010c702000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 device_del+0x9f/0x430 drivers/base/core.c:3092
 device_unregister+0x11/0x50 drivers/base/core.c:3148
 i2c_unregister_device include/linux/err.h:41 [inline]
 __unregister_client+0x3f/0x50 drivers/i2c/i2c-core-base.c:1604
 device_for_each_child+0x4f/0x90 drivers/base/core.c:3248
 i2c_del_adapter+0x1b1/0x300 drivers/i2c/i2c-core-base.c:1667
 pvr2_i2c_core_done+0x1b/0x30 drivers/media/usb/pvrusb2/pvrusb2-i2c-core.c:652
 pvr2_hdw_destroy+0x9a/0x150 drivers/media/usb/pvrusb2/pvrusb2-hdw.c:2679
 pvr2_context_destroy+0x1a/0xb0 drivers/media/usb/pvrusb2/pvrusb2-context.c:70
 pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:137 [inline]
 pvr2_context_thread_func+0x237/0x2c0 drivers/media/usb/pvrusb2/pvrusb2-context.c:158
 kthread+0x144/0x170 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296