bisecting fixing commit since 2d19be4653f5e74ed95560b69f94eb6791d49af3
building syzkaller on 06ed56cd22e24a55c40d152880b66b108834c8f2
testing commit 2d19be4653f5e74ed95560b69f94eb6791d49af3 with gcc (GCC) 8.4.1 20210217
kernel signature: 5f5544ceba0fb542b27d8d94751f961de8d24867faf3fea318c394ed9456dce1
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: KASAN: use-after-free Read in vgem_fence_attach_ioctl
run #5: crashed: general protection fault in vgem_fence_attach_ioctl
run #6: crashed: general protection fault in vgem_fence_attach_ioctl
run #7: crashed: WARNING in mutex_destroy
run #8: crashed: general protection fault in vgem_fence_attach_ioctl
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: 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: general protection fault 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: general protection fault in vgem_fence_attach_ioctl
run #19: crashed: general protection fault in vgem_fence_attach_ioctl
testing current HEAD 2034d6f0838e465dd8f120c4e946d8444b4bb5df
testing commit 2034d6f0838e465dd8f120c4e946d8444b4bb5df with gcc (GCC) 8.4.1 20210217
kernel signature: 8fe18254335488eeecde334069ee5fdceed2fcd630200fecb9145858abb6182c
run #0: crashed: KASAN: use-after-free Read in vgem_fence_attach_ioctl
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: WARNING in mutex_destroy
run #5: crashed: general protection fault in vgem_fence_attach_ioctl
run #6: crashed: WARNING in mutex_destroy
run #7: crashed: WARNING in mutex_destroy
run #8: crashed: WARNING in mutex_destroy
run #9: crashed: general protection fault in vgem_fence_attach_ioctl
revisions tested: 2, total time: 28m13.489766068s (build: 20m51.77156745s, test: 6m43.879138343s)
the crash still happens on HEAD
commit msg: Linux 4.19.184
crash: general protection fault in vgem_fence_attach_ioctl
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: 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
CPU: 1 PID: 10002 Comm: syz-executor.5 Not tainted 4.19.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:vgem_fence_attach_ioctl+0x250/0x580 drivers/gpu/drm/vgem/vgem_fence.c:184
Code: 80 3c 02 00 0f 85 01 03 00 00 4d 8b bc 24 10 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 cd 02 00 00 49 8b 87 e0 00 00 00 4c 89 f2 48 c1
RSP: 0018:ffff88808d6e7a70 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8880b32b72c0 RCX: 0000000000000000
RDX: 000000000000001c RSI: 0000000000000001 RDI: 00000000000000e0
RBP: ffff88808d6e7ab0 R08: ffffed1017464561 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880b32b77c0
R13: ffff8880a860d140 R14: ffff8880b32b72c4 R15: 0000000000000000
FS:  00007f55832d3700(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000025c4708 CR3: 0000000096238000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 drm_ioctl_kernel+0x1b7/0x240 drivers/gpu/drm/drm_ioctl.c:757
 drm_ioctl+0x6a9/0xae0 drivers/gpu/drm/drm_ioctl.c:857
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0x196/0x10c0 fs/ioctl.c:688
 ksys_ioctl+0x62/0x90 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6e/0xb0 fs/ioctl.c:710
 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x465ef9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f55832d3188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000465ef9
RDX: 0000000020000140 RSI: 00000000c10c5541 RDI: 0000000000000003
RBP: 00000000004bfa34 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007ffff010be3f R14: 00007f55832d3300 R15: 0000000000022000
Modules linked in:
---[ end trace e2abbee020f26486 ]---
RIP: 0010:vgem_fence_attach_ioctl+0x250/0x580 drivers/gpu/drm/vgem/vgem_fence.c:184
Code: 80 3c 02 00 0f 85 01 03 00 00 4d 8b bc 24 10 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 cd 02 00 00 49 8b 87 e0 00 00 00 4c 89 f2 48 c1
RSP: 0018:ffff88808d6e7a70 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8880b32b72c0 RCX: 0000000000000000
RDX: 000000000000001c RSI: 0000000000000001 RDI: 00000000000000e0
RBP: ffff88808d6e7ab0 R08: ffffed1017464561 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880b32b77c0
R13: ffff8880a860d140 R14: ffff8880b32b72c4 R15: 0000000000000000
FS:  00007f55832d3700(0000) GS:ffff8880ba300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe504c1c60 CR3: 0000000096238000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400