general protection fault in loop_validate_file

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: b5260801 Linux 4.14.140
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16e2db1e600000
kernel config: https://syzkaller.appspot.com/x/.config?x=a1845e2543d718e1
dashboard link: https://syzkaller.appspot.com/bug?extid=e081281da3b470ee9d84
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e08128...@syzkaller.appspotmail.com

general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
kobject: 'loop0p1' (ffff88805d416698): kobject_cleanup, parent
(null)
CPU: 0 PID: 8902 Comm: syz-executor.1 Not tainted 4.14.140 #36
kobject: 'loop0p1' (ffff88805d416698): calling ktype release
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
kobject: 'loop0p1': free name
task: ffff88805d71e0c0 task.stack: ffff88805d3d8000
RIP: 0010:loop_validate_file+0x206/0x2d0 drivers/block/loop.c:633
RSP: 0018:ffff88805d3dfbc0 EFLAGS: 00010202
RAX: 0000000000000037 RBX: ffff8880a45ad358 RCX: ffffc9000ca73000
kobject: 'loop3' (ffff8880a4ad37e0): kobject_uevent_env
RDX: 0000000000000095 RSI: ffffffff83732115 RDI: 00000000000001b8
RBP: ffff88805d3dfbe0 R08: ffff88805d71e0c0 R09: 0000000000000001
R10: 0000000000000000 R11: ffff88805d71e0c0 R12: 0000000000000000
R13: ffff888088117240 R14: dffffc0000000000 R15: ffff8880a4a27390
FS: 00007ff2ea3a3700(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f22c000 CR3: 000000009c1df000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
loop_set_fd drivers/block/loop.c:897 [inline]
lo_ioctl+0xaa6/0x1ce0 drivers/block/loop.c:1407
kobject: 'loop3' (ffff8880a4ad37e0): fill_kobj_path: path
= '/devices/virtual/block/loop3'
__blkdev_driver_ioctl block/ioctl.c:297 [inline]
blkdev_ioctl+0x96b/0x1860 block/ioctl.c:594
block_ioctl+0xde/0x120 fs/block_dev.c:1881
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459879
RSP: 002b:00007ff2ea3a2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459879
kobject: 'loop3' (ffff8880a4ad37e0): kobject_uevent_env
RDX: 0000000000000003 RSI: 0000000000004c00 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff2ea3a36d4
R13: 00000000004c3061 R14: 00000000004d67a8 R15: 00000000ffffffff
kobject: 'loop3' (ffff8880a4ad37e0): fill_kobj_path: path
= '/devices/virtual/block/loop3'
Code: 00 00 48 89 f8 48 c1 e8 03 42 80 3c 30 00 0f 85 d4 00 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 <42> 80 3c 30
00 0f 85 a8 00 00 00 4d 8b a4 24 b8 01 00 00 4c 89
RIP: loop_validate_file+0x206/0x2d0 drivers/block/loop.c:633 RSP:
ffff88805d3dfbc0
kobject: 'loop5' (ffff8880a4b629a0): kobject_uevent_env
IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready
kobject: 'loop5' (ffff8880a4b629a0): fill_kobj_path: path
= '/devices/virtual/block/loop5'
chnl_net:chnl_net_open(): err: Unable to register and open device, Err:-19
caif:caif_disconnect_client(): nothing to disconnect
kobject: 'loop3' (ffff8880a4ad37e0): kobject_uevent_env
---[ end trace cd909235d61ef543 ]---


---
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[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: 01fd1694 Linux 4.14.141
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13be8dda600000
kernel config: https://syzkaller.appspot.com/x/.config?x=62c9b69e1b2adda9

dashboard link: https://syzkaller.appspot.com/bug?extid=e081281da3b470ee9d84
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1390f4fa600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13340761600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e08128...@syzkaller.appspotmail.com

IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready
hrtimer: interrupt took 24701 ns
kasan: CONFIG_KASAN_INLINE enabled
kobject: 'loop4' (ffff8880a4b1d460): kobject_uevent_env
kasan: GPF could be caused by NULL-ptr deref or user memory access

general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:

kobject: 'loop4' (ffff8880a4b1d460): fill_kobj_path: path
= '/devices/virtual/block/loop4'
CPU: 1 PID: 6787 Comm: syz-executor777 Not tainted 4.14.141 #37

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011

task: ffff88808fbf2180 task.stack: ffff888087d08000

RIP: 0010:loop_validate_file+0x206/0x2d0 drivers/block/loop.c:633

RSP: 0018:ffff888087d0fbc0 EFLAGS: 00010202
RAX: 0000000000000037 RBX: ffff8880a77b6218 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880a77e0700 RDI: 00000000000001b8
RBP: ffff888087d0fbe0 R08: ffff88808fbf2180 R09: 0000000000000001
R10: 0000000000000000 R11: ffff88808fbf2180 R12: 0000000000000000
R13: ffff8880a77e0700 R14: dffffc0000000000 R15: ffff888219561c90
FS: 00007f1c27602700(0000) GS:ffff8880aef00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f1c27601db8 CR3: 0000000085fbb000 CR4: 00000000001406e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
loop_set_fd drivers/block/loop.c:897 [inline]
lo_ioctl+0xaa6/0x1ce0 drivers/block/loop.c:1407

__blkdev_driver_ioctl block/ioctl.c:297 [inline]
blkdev_ioctl+0x96b/0x1860 block/ioctl.c:594
block_ioctl+0xde/0x120 fs/block_dev.c:1881
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7

RIP: 0033:0x44dc49
RSP: 002b:00007f1c27601ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006e6a18 RCX: 000000000044dc49
RDX: 0000000000000006 RSI: 0000000000004c00 RDI: 0000000000000004
RBP: 00000000006e6a10 R08: 00007f1c27602700 R09: 0000000000000000
R10: 00007f1c27602700 R11: 0000000000000246 R12: 00000000006e6a1c
R13: 00007fff92f63faf R14: 00007f1c276029c0 R15: 0000000000000001

Code: 00 00 48 89 f8 48 c1 e8 03 42 80 3c 30 00 0f 85 d4 00 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 <42> 80 3c 30
00 0f 85 a8 00 00 00 4d 8b a4 24 b8 01 00 00 4c 89
RIP: loop_validate_file+0x206/0x2d0 drivers/block/loop.c:633 RSP:

ffff888087d0fbc0
---[ end trace fa376e453dbfae2f ]---