bisecting fixing commit since 0f1b4cb77d7f5a442b03f8ad597768b422e8ec58 building syzkaller on c59079a693ad1d89c782f7db14b9f1c5629e2abc testing commit 0f1b4cb77d7f5a442b03f8ad597768b422e8ec58 with gcc (GCC) 8.4.1 20210217 kernel signature: 22d2329336822f21a33861a1e173a52101e7468cd1b389166374f0a45a301e95 all runs: crashed: WARNING in drm_prime_destroy_file_private testing current HEAD 9a2dc0e6c531d595bcdf2c66d0be131679bd02df testing commit 9a2dc0e6c531d595bcdf2c66d0be131679bd02df with gcc (GCC) 8.4.1 20210217 kernel signature: bd19b2cabe02b04f5235744fe4ef79f7b0b97342409767ed774e9ea38be6f1b6 all runs: crashed: WARNING in drm_prime_destroy_file_private revisions tested: 2, total time: 23m5.875914271s (build: 16m3.63482994s, test: 6m39.275013145s) the crash still happens on HEAD commit msg: Linux 4.19.194 crash: WARNING in drm_prime_destroy_file_private IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready ------------[ cut here ]------------ WARNING: CPU: 1 PID: 10049 at drivers/gpu/drm/drm_prime.c:982 drm_prime_destroy_file_private.cold.6+0xc/0x13 drivers/gpu/drm/drm_prime.c:982 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 10049 Comm: syz-executor.4 Not tainted 4.19.194-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x17c/0x226 lib/dump_stack.c:118 panic+0x1cd/0x375 kernel/panic.c:186 __warn.cold.7+0x1b/0x36 kernel/panic.c:541 report_bug+0x1a1/0x200 lib/bug.c:183 fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [inline] do_error_trap+0x200/0x350 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038 RIP: 0010:drm_prime_destroy_file_private.cold.6+0xc/0x13 drivers/gpu/drm/drm_prime.c:982 Code: 8b 45 c8 e9 55 5d 17 fc 48 c7 c7 a0 80 60 88 e8 bb 4d f6 ff 0f 0b 83 c8 ff e9 e5 62 17 fc 48 c7 c7 a0 80 60 88 e8 a5 4d f6 ff <0f> 0b e9 1f 6d 17 fc 48 c7 c7 c0 85 60 88 e8 92 4d f6 ff 0f 0b e9 RSP: 0018:ffff88809680fd28 EFLAGS: 00010282 RAX: 0000000000000024 RBX: ffff888096030768 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff88502040 RDI: ffffffff8bad8720 RBP: ffff88809680fd30 R08: ffffed1017464e99 R09: ffffed1017464e98 R10: ffffed1017464e98 R11: ffff8880ba3274c7 R12: ffff8882389a4300 R13: ffff8880960306d0 R14: ffff8882389a4320 R15: ffffffff89f4af00 drm_file_free.part.0+0x7ed/0xc30 drivers/gpu/drm/drm_file.c:257 drm_file_free drivers/gpu/drm/drm_file.c:215 [inline] drm_release+0x1ee/0x350 drivers/gpu/drm/drm_file.c:480 __fput+0x249/0x7f0 fs/file_table.c:278 ____fput+0x9/0x10 fs/file_table.c:309 task_work_run+0x108/0x180 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x185/0x1e0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x41926b Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44 RSP: 002b:00007fff9c511520 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 000000000041926b RDX: 0000000000570a78 RSI: 0000000000000080 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000005709a0 R10: 00007fff9c511610 R11: 0000000000000293 R12: 000000000001072a R13: 00000000000003e8 R14: 000000000056bf60 R15: 0000000000010700 Kernel Offset: disabled Rebooting in 86400 seconds..