general protection fault in drm_dp_aux_dev_get_by_minor

Status: upstream: reported C repro on 2020/06/08 05:41
First crash: 1472d, last: 1472d
Fix bisection the fix commit could be any of (bisect log):
  c6db52a88798 Linux 4.14.183
  4139fb08c05f Linux 4.14.187
Last patch testing requests (2)
Created Duration User Patch Repo Result
2023/01/23 14:32 10m retest repro linux-4.14.y report log
2022/09/06 09:27 12m retest repro linux-4.14.y report log

Sample crash report:
MINIX-fs: mounting unchecked file system, running fsck is recommended
audit: type=1800 audit(1591596169.797:9): pid=6334 uid=0 auid=0 ses=5 subj=system_u:system_r:kernel_t:s0 op="collect_data" cause="failed(directio)" comm="syz-executor608" name="file0" dev="sda1" ino=15705 res=0
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: 6334 Comm: syz-executor608 Not tainted 4.14.183-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880978ba080 task.stack: ffff888088880000
RIP: 0010:__read_once_size include/linux/compiler.h:183 [inline]
RIP: 0010:atomic_read arch/x86/include/asm/atomic.h:27 [inline]
RIP: 0010:refcount_add_not_zero arch/x86/include/asm/refcount.h:84 [inline]
RIP: 0010:refcount_inc_not_zero arch/x86/include/asm/refcount.h:106 [inline]
RIP: 0010:kref_get_unless_zero include/linux/kref.h:116 [inline]
RIP: 0010:drm_dp_aux_dev_get_by_minor+0x41/0xd0 drivers/gpu/drm/drm_dp_aux_dev.c:63
RSP: 0018:ffff8880888879d8 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 00000000000000b1 RCX: 0000000000000000
RDX: 0000000000000003 RSI: 00000000000000b1 RDI: ffffffff8801b5c0
RBP: 0000000000000018 R08: ffffffff8a380bc0 R09: 0000000000000002
R10: ffff8880888879d8 R11: ffff8880978ba080 R12: 0000000000000000
R13: ffff8880a97e7d40 R14: ffffffff8353b400 R15: ffff8880a97e7d68
FS:  00000000024c7940(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555568613b88 CR3: 00000000a8bf4000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 auxdev_open+0x47/0xa0 drivers/gpu/drm/drm_dp_aux_dev.c:131
 chrdev_open+0x1fc/0x540 fs/char_dev.c:423
 do_dentry_open+0x44b/0xec0 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:888
 do_last fs/namei.c:3428 [inline]
 path_openat+0xb68/0x2aa0 fs/namei.c:3569
 do_filp_open+0x18e/0x250 fs/namei.c:3603
 file_open_name+0x206/0x260 fs/open.c:1008
 acct_on kernel/acct.c:207 [inline]
 SYSC_acct kernel/acct.c:286 [inline]
 SyS_acct+0xcb/0x850 kernel/acct.c:273
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
RIP: 0033:0x444ac9
RSP: 002b:00007ffc3e098d18 EFLAGS: 00000246 ORIG_RAX: 00000000000000a3
RAX: ffffffffffffffda RBX: 00007ffc3e098d20 RCX: 0000000000444ac9
RDX: 0000000000401470 RSI: 76a48c1cd11c080b RDI: 0000000020000480
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000400eb0
R10: 00007ffc3e098bf0 R11: 0000000000000246 R12: 0000000000402730
R13: 00000000004027c0 R14: 0000000000000000 R15: 0000000000000000
Code: e8 15 eb e9 02 89 de 48 c7 c7 c0 b5 01 88 e8 c7 56 e5 02 48 8d 68 18 49 89 c4 48 b8 00 00 00 00 00 fc ff df 48 89 ea 48 c1 ea 03 <0f> b6 14 02 48 89 e8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 66 
RIP: __read_once_size include/linux/compiler.h:183 [inline] RSP: ffff8880888879d8
RIP: atomic_read arch/x86/include/asm/atomic.h:27 [inline] RSP: ffff8880888879d8
RIP: refcount_add_not_zero arch/x86/include/asm/refcount.h:84 [inline] RSP: ffff8880888879d8
RIP: refcount_inc_not_zero arch/x86/include/asm/refcount.h:106 [inline] RSP: ffff8880888879d8
RIP: kref_get_unless_zero include/linux/kref.h:116 [inline] RSP: ffff8880888879d8
RIP: drm_dp_aux_dev_get_by_minor+0x41/0xd0 drivers/gpu/drm/drm_dp_aux_dev.c:63 RSP: ffff8880888879d8
---[ end trace 3645b4fd0cf0886f ]---

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/06/08 06:05 linux-4.14.y c6db52a88798 7751efd0 .config console log report syz C ci2-linux-4-14
2020/06/08 05:40 linux-4.14.y c6db52a88798 7751efd0 .config console log report ci2-linux-4-14
* Struck through repros no longer work on HEAD.