bisecting fixing commit since 45f092f9e9cb31486db546e39bfe7cc0b3f57099
building syzkaller on 78ded1969a3882c1a5dc9cf32ed2ffc23119a4ca
testing commit 45f092f9e9cb31486db546e39bfe7cc0b3f57099 with gcc (GCC) 8.1.0
kernel signature: 8b2406eeee6625fa8aa99f5653384464aa7eec5d6d1a3903544dc1ccf06d742e
all runs: crashed: general protection fault in sysfs_do_create_link_sd
testing current HEAD 14b58326976de6ef3998eefec1dd7f8b38b97a75
testing commit 14b58326976de6ef3998eefec1dd7f8b38b97a75 with gcc (GCC) 8.1.0
kernel signature: 96798e4410bb55958ff732f3370d60b5113ddaf2135e78f010dc3dbbd24a1136
all runs: crashed: general protection fault in sysfs_do_create_link_sd
revisions tested: 2, total time: 25m21.783261508s (build: 17m23.167484225s, test: 6m33.034483755s)
the crash still happens on HEAD
commit msg: Linux 4.14.193
crash: general protection fault in sysfs_do_create_link_sd
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f65183946d4
R13: 00000000004c3027 R14: 00000000004d6768 R15: 0000000000000004
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: 7718 Comm: syz-executor.2 Not tainted 4.14.193-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888083a5a640 task.stack: ffff888083be8000
RIP: 0010:sysfs_do_create_link_sd.isra.2+0x48/0xf0 fs/sysfs/symlink.c:35
RSP: 0018:ffff888083befab0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffffffff86bbc220 RCX: ffff888083a5aec8
RDX: 0000000000000008 RSI: ffff888083a5aef0 RDI: ffffffff87a630e4
RBP: ffff888083befad8 R08: ffff888083a5af10 R09: 0000000000004fb4
R10: 0000000000000028 R11: ffff888083a5a640 R12: ffff88809007b380
R13: 0000000000000040 R14: 0000000000000001 R15: ffff88808f5446d0
FS:  00007f6518394700(0000) GS:ffff8880aef00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000259e978 CR3: 000000009061d000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 sysfs_do_create_link fs/sysfs/symlink.c:80 [inline]
 sysfs_create_link+0x43/0xb0 fs/sysfs/symlink.c:92
 device_add_disk+0x981/0xd50 block/genhd.c:688
 add_disk include/linux/genhd.h:396 [inline]
 loop_add+0x5e2/0x810 drivers/block/loop.c:1904
 loop_control_ioctl+0x19e/0x2b0 drivers/block/loop.c:2001
 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: 0033:0x4598f9
RSP: 002b:00007f6518393c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6518393c90 RCX: 00000000004598f9
RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000003
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f65183946d4
R13: 00000000004c3027 R14: 00000000004d6768 R15: 0000000000000004
Code: 00 00 49 89 f5 49 89 fc 48 c7 c7 e0 30 a6 87 48 89 d3 41 89 ce e8 89 5b 79 04 4c 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 86 00 00 00 4d 8b 6d 00 4d 85 ed 74 52 4c 89 
RIP: sysfs_do_create_link_sd.isra.2+0x48/0xf0 fs/sysfs/symlink.c:35 RSP: ffff888083befab0
---[ end trace 87d0259f4ccee6fe ]---