bisecting fixing commit since c196b3a9c83ae3491280b739d231d02b3cb9d041
building syzkaller on 0ef84591d219e3142621dc31dcec970300f7ec0c
testing commit c196b3a9c83ae3491280b739d231d02b3cb9d041 with gcc (GCC) 8.4.1 20210217
kernel signature: 7f92f40b7b048282961c4f69671928ceba6c1ba3bfd337c6d01f09e461165452
run #0: crashed: WARNING in mutex_destroy
run #1: crashed: general protection fault in vgem_fence_attach_ioctl
run #2: crashed: general protection fault in vgem_fence_attach_ioctl
run #3: crashed: general protection fault in vgem_fence_attach_ioctl
run #4: crashed: general protection fault in vgem_fence_attach_ioctl
run #5: crashed: WARNING in mutex_destroy
run #6: crashed: general protection fault in vgem_fence_attach_ioctl
run #7: crashed: general protection fault in vgem_fence_attach_ioctl
run #8: crashed: WARNING in mutex_destroy
run #9: crashed: general protection fault in vgem_fence_attach_ioctl
run #10: crashed: general protection fault in vgem_fence_attach_ioctl
run #11: crashed: general protection fault in vgem_fence_attach_ioctl
run #12: crashed: general protection fault in vgem_fence_attach_ioctl
run #13: crashed: general protection fault in vgem_fence_attach_ioctl
run #14: crashed: general protection fault in vgem_fence_attach_ioctl
run #15: crashed: general protection fault in vgem_fence_attach_ioctl
run #16: crashed: WARNING in mutex_destroy
run #17: crashed: general protection fault in vgem_fence_attach_ioctl
run #18: crashed: general protection fault in vgem_fence_attach_ioctl
run #19: crashed: general protection fault in vgem_fence_attach_ioctl
testing current HEAD 670d6552eda8ff0c5f396d3d6f0174237917c66c
testing commit 670d6552eda8ff0c5f396d3d6f0174237917c66c with gcc (GCC) 8.4.1 20210217
kernel signature: 361001e29e5bcfe1f9b91759f137175a135b42dff7b02e4d66ebad6fe851523f
run #0: crashed: general protection fault in vgem_fence_attach_ioctl
run #1: crashed: general protection fault in vgem_fence_attach_ioctl
run #2: crashed: WARNING in mutex_destroy
run #3: crashed: general protection fault in vgem_fence_attach_ioctl
run #4: crashed: KASAN: use-after-free Read in vgem_fence_attach_ioctl
run #5: crashed: general protection fault in vgem_fence_attach_ioctl
run #6: crashed: WARNING in mutex_destroy
run #7: crashed: general protection fault in vgem_fence_attach_ioctl
run #8: crashed: general protection fault in vgem_fence_attach_ioctl
run #9: crashed: general protection fault in vgem_fence_attach_ioctl
revisions tested: 2, total time: 20m46.942190517s (build: 14m5.208942494s, test: 6m13.01997562s)
the crash still happens on HEAD
commit msg: Linux 4.14.227
crash: general protection fault in vgem_fence_attach_ioctl
IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 9898 Comm: syz-executor.0 Not tainted 4.14.227-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880b4f3c340 task.stack: ffff88809b0f8000
RIP: 0010:vgem_fence_attach_ioctl+0x2f2/0x6d0 drivers/gpu/drm/vgem/vgem_fence.c:184
RSP: 0018:ffff88809b0ffb40 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88809659d580 RCX: 0000000000000000
RDX: 000000000000001c RSI: 0000000000000001 RDI: 00000000000000e0
RBP: ffff88809b0ffbe8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880aa272800
R13: ffff8880a9f8ad40 R14: ffff8880aa272804 R15: 0000000000000000
FS:  00007f9117353700(0000) GS:ffff8880ba700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000009add1000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 drm_ioctl_kernel+0x133/0x1d0 drivers/gpu/drm/drm_ioctl.c:736
 drm_ioctl+0x417/0x900 drivers/gpu/drm/drm_ioctl.c:836
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x180/0xfb0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x74/0x80 fs/ioctl.c:692
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x465889
RSP: 002b:00007f9117353188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000055bf00 RCX: 0000000000465889
RDX: 0000000020000140 RSI: 00000000c10c5541 RDI: 0000000000000003
RBP: 00000000004af688 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bf00
R13: 00007ffda13c7d1f R14: 00007f9117353300 R15: 0000000000022000
Code: ea 03 80 3c 02 00 0f 85 93 03 00 00 4d 8b bd 18 01 00 00 48 b8 00 00 00 00 00 fc ff df 49 8d bf e0 00 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 8f 03 00 00 49 8b 87 e0 00 00 00 4c 89 f2 48 
RIP: vgem_fence_attach_ioctl+0x2f2/0x6d0 drivers/gpu/drm/vgem/vgem_fence.c:184 RSP: ffff88809b0ffb40
---[ end trace f76b969f93a6cb2f ]---