bisecting fixing commit since 958e517f4e16952e9a2e2d58fd32d28ae4e23dda
building syzkaller on fcdb12ba70875c410749932abf39160d19c753d9
testing commit 958e517f4e16952e9a2e2d58fd32d28ae4e23dda with gcc (GCC) 8.4.1 20210217
kernel signature: 5d4a146b2b38c384f2810ea4a5a3779f9a65ddb002235fa2ebf810ca33ec79b9
all runs: crashed: WARNING in drm_prime_destroy_file_private
testing current HEAD 7d7d1c0ab3eb7c8d8f63a126535018007823b207
testing commit 7d7d1c0ab3eb7c8d8f63a126535018007823b207 with gcc (GCC) 8.4.1 20210217
kernel signature: 70e9bdcf51f0e116edf9597a9413302577e2b96a572841a745f07367662118a4
all runs: crashed: WARNING in drm_prime_destroy_file_private
revisions tested: 2, total time: 20m12.733891947s (build: 13m40.010456872s, test: 6m10.346814495s)
the crash still happens on HEAD
commit msg: Linux 4.14.232
crash: WARNING in drm_prime_destroy_file_private
Bluetooth: hci0 command 0x0419 tx timeout
Bluetooth: hci3 command 0x0419 tx timeout
Bluetooth: hci4 command 0x0419 tx timeout
Bluetooth: hci5 command 0x0419 tx timeout
------------[ cut here ]------------
WARNING: CPU: 0 PID: 9872 at drivers/gpu/drm/drm_prime.c:898 drm_prime_destroy_file_private+0x32/0x40 drivers/gpu/drm/drm_prime.c:899
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 9872 Comm: syz-executor.2 Not tainted 4.14.232-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x14b/0x1e7 lib/dump_stack.c:58
 panic+0x1b0/0x358 kernel/panic.c:183
 __warn.cold.7+0x25/0x25 kernel/panic.c:547
 report_bug+0x1a1/0x200 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 fixup_bug arch/x86/kernel/traps.c:172 [inline]
 do_error_trap+0x1bd/0x310 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:964
RIP: 0010:drm_prime_destroy_file_private+0x32/0x40 drivers/gpu/drm/drm_prime.c:898
RSP: 0018:ffff8880b382fd40 EFLAGS: 00010282
RAX: ffff8880b4df6a10 RBX: ffff888095f83478 RCX: 1ffff1101676096d
RDX: 1ffff11012bf069f RSI: ffff8880b3b04b48 RDI: ffff888095f834f8
RBP: ffff8880b382fd48 R08: ffff8880b3b04b68 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888238542180
R13: ffff8882385421a0 R14: ffff888095f833e0 R15: ffffffff894dd200
 drm_release+0xa45/0xf40 drivers/gpu/drm/drm_file.c:427
 __fput+0x232/0x740 fs/file_table.c:210
 ____fput+0x9/0x10 fs/file_table.c:244
 task_work_run+0xe5/0x170 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x14a/0x190 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x416/0x5b0 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x466459
RSP: 002b:00007f55fa0a4188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 000000000056bf60 RCX: 0000000000466459
RDX: 0000000020000140 RSI: 00000000c10c5541 RDI: 0000000000000003
RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007ffdab15c0bf R14: 00007f55fa0a4300 R15: 0000000000022000
Kernel Offset: disabled
Rebooting in 86400 seconds..