bisecting fixing commit since cbfa1702aaf69b2311ea1b35e04f113c48368c67
building syzkaller on 4a77ae0bdc5cd75ebe88ce7c896aae6bbf457a29
testing commit cbfa1702aaf69b2311ea1b35e04f113c48368c67 with gcc (GCC) 8.4.1 20210217
kernel signature: 7492f36bf9ed58ee4f653e0ee352a28d2cf05944334538363f30dbc9d3570e75
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: 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: WARNING in mutex_destroy
run #16: crashed: WARNING in mutex_destroy
run #17: crashed: general protection fault in vgem_fence_attach_ioctl
run #18: crashed: WARNING in mutex_destroy
run #19: crashed: general protection fault in vgem_fence_attach_ioctl
testing current HEAD cb83ddcd5332fcc3efd52ba994976efc4dd6061e
testing commit cb83ddcd5332fcc3efd52ba994976efc4dd6061e with gcc (GCC) 8.4.1 20210217
kernel signature: 79607ba23b36c0375881359aa5ccbf64615074ad4d70f22408dcae2b75b628e3
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: general protection fault in vgem_fence_attach_ioctl
run #6: crashed: KASAN: use-after-free Read in reservation_object_test_signaled_rcu
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: 35m37.274116847s (build: 15m6.73010478s, test: 20m8.302242508s)
the crash still happens on HEAD
commit msg: Linux 4.14.226
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: 0 PID: 13602 Comm: syz-executor207 Not tainted 4.14.226-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8881e8f74400 task.stack: ffff8881e94c8000
RIP: 0010:vgem_fence_attach_ioctl+0x2f2/0x6d0 drivers/gpu/drm/vgem/vgem_fence.c:184
RSP: 0018:ffff8881e94cfb40 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8881e5e01780 RCX: 0000000000000000
RDX: 000000000000001c RSI: 0000000000000001 RDI: 00000000000000e0
RBP: ffff8881e94cfbe8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881d7088080
R13: ffff8881d6d4e780 R14: ffff8881d7088084 R15: 0000000000000000
FS:  00007ff9efd9a700(0000) GS:ffff8881f6600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff9efd99ee8 CR3: 00000001ee802005 CR4: 00000000001606f0
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:00007ff9efd9a308 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: ffff8881e94cfb40
---[ end trace 3dfccd393d912d75 ]---