bisecting fixing commit since 01fd1694b93c92ad54fa684dac9c8068ecda8288
building syzkaller on 526709ff0442e985edd498e14c736de8302dc867
testing commit 01fd1694b93c92ad54fa684dac9c8068ecda8288 with gcc (GCC) 8.1.0
kernel signature: 5d1d4240c8dd11d22ee18c7d63d4beae4cbe068663d24781e9e84c67f791e78f
all runs: crashed: general protection fault in loop_validate_file
testing current HEAD 4520f06b03ae667e442da1ab9351fd28cd7ac598
testing commit 4520f06b03ae667e442da1ab9351fd28cd7ac598 with gcc (GCC) 8.1.0
kernel signature: 3663bf8f302956ef89e55f232afe32007a3205be1e08e78ea2b03d5f6da93838
all runs: crashed: general protection fault in loop_validate_file
revisions tested: 2, total time: 24m34.41415122s (build: 16m17.509144486s, test: 7m17.223545893s)
the crash still happens on HEAD
commit msg: Linux 4.14.175
crash: general protection fault in loop_validate_file
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: 18794 Comm: syz-executor.0 Not tainted 4.14.175-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880926d8640 task.stack: ffff888081c28000
RIP: 0010:loop_validate_file+0x1da/0x430 drivers/block/loop.c:643
RSP: 0018:ffff888081c2fb68 EFLAGS: 00010202
RAX: 0000000000000037 RBX: dffffc0000000000 RCX: 1ffff110124db1d6
RDX: 1ffff1101493ce71 RSI: ffff8880a77eb780 RDI: 00000000000001b8
RBP: ffff888081c2fb80 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000028 R11: ffff8880926d8640 R12: 0000000000000000
R13: 00000000fffffff0 R14: ffff88809832c500 R15: ffff8880a77eb860
FS:  00007fa04a1f0700(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000075c000 CR3: 00000000a99cb000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 loop_set_fd drivers/block/loop.c:907 [inline]
 lo_ioctl+0x95f/0x1c70 drivers/block/loop.c:1417
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x784/0x16b0 block/ioctl.c:594
 block_ioctl+0xd7/0x130 fs/block_dev.c:1881
 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+0x42/0xb7
RIP: 0033:0x459879
RSP: 002b:00007fa04a1efc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459879
RDX: 0000000000000006 RSI: 0000000000004c00 RDI: 0000000000000004
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa04a1f06d4
R13: 00000000004c2f80 R14: 00000000004d66b8 R15: 00000000ffffffff
Code: 00 00 00 48 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 10 02 00 00 4d 8b a4 24 f0 00 00 00 49 8d bc 24 b8 01 00 00 48 89 f8 48 c1 e8 03 <80> 3c 18 00 0f 85 dd 01 00 00 4d 8b a4 24 b8 01 00 00 4c 89 e0 
RIP: loop_validate_file+0x1da/0x430 drivers/block/loop.c:643 RSP: ffff888081c2fb68
---[ end trace 1431d4209571dd27 ]---