bisecting fixing commit since 45f092f9e9cb31486db546e39bfe7cc0b3f57099
building syzkaller on 78ded1969a3882c1a5dc9cf32ed2ffc23119a4ca
testing commit 45f092f9e9cb31486db546e39bfe7cc0b3f57099 with gcc (GCC) 8.4.1 20210217
kernel signature: 073e41d915aed5df20c9e1cf3b1b00d3e6465d426b027c5a0cc3dd2b773d3c21
all runs: crashed: general protection fault in sysfs_do_create_link_sd
testing current HEAD 1d177c0872ab99ac8d1fe09376a56c2911a837c0
testing commit 1d177c0872ab99ac8d1fe09376a56c2911a837c0 with gcc (GCC) 8.4.1 20210217
kernel signature: 79f4525709ef1a3a3fb168e30f48d3a6e7f44bab324c42460c77c3b57b24a729
all runs: crashed: general protection fault in sysfs_do_create_link_sd
revisions tested: 2, total time: 23m54.210590934s (build: 15m47.954777395s, test: 7m22.938892535s)
the crash still happens on HEAD
commit msg: Linux 4.14.224
crash: general protection fault in sysfs_do_create_link_sd
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 00000000004ef248 R14: 00000000004aecdc R15: 00007f6fdb5c36bc
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: 7111 Comm: syz-executor.1 Not tainted 4.14.224-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8881e3696180 task.stack: ffff8881d3a90000
RIP: 0010:sysfs_do_create_link_sd.isra.2+0x48/0xf0 fs/sysfs/symlink.c:35
RSP: 0018:ffff8881d3a97ab0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffffffff86bbc800 RCX: ffff8881e3696a08
RDX: 0000000000000008 RSI: ffff8881e3696a30 RDI: ffffffff87a63064
RBP: ffff8881d3a97ad8 R08: ffff8881e3696a50 R09: 0000000000007e95
R10: 0000000000000028 R11: ffff8881e3696180 R12: ffff8881e1622540
R13: 0000000000000040 R14: 0000000000000001 R15: ffff8881e2174910
FS:  00007f6fdb5c3700(0000) GS:ffff8881f6900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd3a86af000 CR3: 00000001e25eb005 CR4: 00000000001606e0
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:691
 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: 0033:0x4610d9
RSP: 002b:00007f6fdb5c31a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000052bfa8 RCX: 00000000004610d9
RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000003
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000004
R13: 00000000004ef248 R14: 00000000004aecdc R15: 00007f6fdb5c36bc
Code: 00 00 49 89 f5 49 89 fc 48 c7 c7 60 30 a6 87 48 89 d3 41 89 ce e8 a9 20 7e 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: ffff8881d3a97ab0
---[ end trace 3ea5c7a9b7425689 ]---