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Date:   Fri, 30 Mar 2018 13:01:02 -0700
Message-ID: <0000000000001f05330568a6b369@google.com>
Subject: WARNING: kmalloc bug in bfs_fill_super
From:   syzbot <syzbot+71c6b5d68e91149fc8a4@syzkaller.appspotmail.com>
To:     aivazian.tigran@gmail.com, linux-kernel@vger.kernel.org,
        syzkaller-bugs@googlegroups.com
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Hello,

syzbot hit the following crash on upstream commit
9dd2326890d89a5179967c947dab2bab34d7ddee (Fri Mar 30 17:29:47 2018 +0000)
Merge tag 'ceph-for-4.16-rc8' of git://github.com/ceph/ceph-client
syzbot dashboard link:  
https://syzkaller.appspot.com/bug?extid=71c6b5d68e91149fc8a4

So far this crash happened 2 times on upstream.
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=4931648743276544
syzkaller reproducer:  
https://syzkaller.appspot.com/x/repro.syz?id=5311241039904768
Raw console output:  
https://syzkaller.appspot.com/x/log.txt?id=6519557879496704
Kernel config:  
https://syzkaller.appspot.com/x/.config?id=-2760467897697295172
compiler: gcc (GCC) 7.1.1 20170620

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+71c6b5d68e91149fc8a4@syzkaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for  
details.
If you forward the report, please keep this part and the footer.

BFS-fs: bfs_fill_super(): loop0 is unclean, continuing
WARNING: CPU: 1 PID: 4468 at mm/slab_common.c:1012 kmalloc_slab+0x5d/0x70  
mm/slab_common.c:1012
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4468 Comm: syzkaller458727 Not tainted 4.16.0-rc7+ #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:17 [inline]
  dump_stack+0x194/0x24d lib/dump_stack.c:53
  panic+0x1e4/0x41c kernel/panic.c:183
  __warn+0x1dc/0x200 kernel/panic.c:547
  report_bug+0x1f4/0x2b0 lib/bug.c:186
  fixup_bug.part.10+0x37/0x80 arch/x86/kernel/traps.c:178
  fixup_bug arch/x86/kernel/traps.c:247 [inline]
  do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296
  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
  invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:986
RIP: 0010:kmalloc_slab+0x5d/0x70 mm/slab_common.c:1012
RSP: 0018:ffff8801ad117908 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8801b904e004 RCX: ffffffff820931da
RDX: 1ffff1003a1dfac4 RSI: 0000000000000000 RDI: 0000000000800000
RBP: ffff8801ad117908 R08: 1ffff10035a22e81 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000007fffff
R13: ffff8801b904e000 R14: 00000000014080c0 R15: ffff8801d9194cc0
  __do_kmalloc mm/slab.c:3701 [inline]
  __kmalloc+0x25/0x760 mm/slab.c:3715
  kmalloc include/linux/slab.h:517 [inline]
  kzalloc include/linux/slab.h:701 [inline]
  bfs_fill_super+0x3d3/0xea0 fs/bfs/inode.c:362
  mount_bdev+0x2b7/0x370 fs/super.c:1119
  bfs_mount+0x34/0x40 fs/bfs/inode.c:465
  mount_fs+0x66/0x2d0 fs/super.c:1222
  vfs_kern_mount.part.26+0xc6/0x4a0 fs/namespace.c:1037
  vfs_kern_mount fs/namespace.c:2509 [inline]
  do_new_mount fs/namespace.c:2512 [inline]
  do_mount+0xea4/0x2bb0 fs/namespace.c:2842
  SYSC_mount fs/namespace.c:3058 [inline]
  SyS_mount+0xab/0x120 fs/namespace.c:3035
  do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x442d3a
RSP: 002b:00007ffd0d12ac38 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000442d3a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffd0d12ac40
RBP: 0000000000000004 R08: 0000000000000000 R09: 000000000000000a
R10: 00000000c0ed0000 R11: 0000000000000297 R12: 0000000000401ba0
R13: 0000000000401c30 R14: 0000000000000000 R15: 0000000000000000
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


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