bisecting fixing commit since cbfa1702aaf69b2311ea1b35e04f113c48368c67
building syzkaller on 4a77ae0bdc5cd75ebe88ce7c896aae6bbf457a29
testing commit cbfa1702aaf69b2311ea1b35e04f113c48368c67 with gcc (GCC) 8.4.1 20210217
kernel signature: 11e750f48e37ddf8c583a147efd5c766284cdbe668d0b3b9e67ecffebfa92f59
run #0: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #1: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #2: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #3: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #4: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #5: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #6: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #7: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #8: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #9: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #10: crashed: WARNING in mutex_destroy
run #11: crashed: WARNING in mutex_destroy
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: KASAN: use-after-free Read in vgem_fence_attach_ioctl
run #15: crashed: WARNING in mutex_destroy
run #16: crashed: general protection fault in vgem_fence_attach_ioctl
run #17: crashed: general protection fault in vgem_fence_attach_ioctl
run #18: crashed: WARNING in mutex_destroy
run #19: crashed: WARNING in mutex_destroy
testing current HEAD cf256fbcbe347b7d0ff58fe2dfa382a156bd3694
testing commit cf256fbcbe347b7d0ff58fe2dfa382a156bd3694 with gcc (GCC) 8.4.1 20210217
kernel signature: 3a0d2dae686bebaf5a6ecbe99a75b10941c3a6d17851bb708ab945061d94a2d4
run #0: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #1: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #2: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #3: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #4: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #5: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #6: crashed: KASAN: use-after-free Read in vgem_gem_dumb_create
run #7: crashed: general protection fault in vgem_fence_attach_ioctl
run #8: crashed: general protection fault in vgem_fence_attach_ioctl
run #9: OK
revisions tested: 2, total time: 38m58.372835656s (build: 16m2.217309207s, test: 22m33.023725247s)
the crash still happens on HEAD
commit msg: Linux 4.14.231
crash: general protection fault in vgem_fence_attach_ioctl
bond0 (unregistering): Releasing backup interface bond_slave_1
bond0 (unregistering): Releasing backup interface bond_slave_0
bond0 (unregistering): Released all slaves
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: 7941 Comm: syz-executor826 Not tainted 4.14.231-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8881df6866c0 task.stack: ffff8881d2430000
RIP: 0010:vgem_fence_attach_ioctl+0x2f2/0x6d0 drivers/gpu/drm/vgem/vgem_fence.c:184
RSP: 0018:ffff8881d2437b40 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8881ea17d300 RCX: 0000000000000000
RDX: 000000000000001c RSI: 0000000000000001 RDI: 00000000000000e0
RBP: ffff8881d2437be8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881e2c9ba40
R13: ffff8881e29ad340 R14: ffff8881e2c9ba44 R15: 0000000000000000
FS:  00007f62ae174700(0000) GS:ffff8881f6700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f62ae173ee8 CR3: 00000001c4b47001 CR4: 00000000001606e0
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: 0033:0x449e69
RSP: 002b:00007f62ae174308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004ca428 RCX: 0000000000449e69
RDX: 0000000020000140 RSI: 00000000c10c5541 RDI: 0000000000000004
RBP: 00000000004ca420 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004ca42c
R13: 000000000049a064 R14: 6972642f7665642f 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: ffff8881d2437b40
---[ end trace 3ee919d3ba9ce862 ]---