Message-ID: <0000000000008c012905708aa7bf@google.com>
Date:   Sun, 08 Jul 2018 22:55:02 -0700
From:   syzbot <syzbot+ad37a4e3a54f2dbc5546@...kaller.appspotmail.com>
To:     davem@...emloft.net, ericvh@...il.com,
        linux-kernel@...r.kernel.org, lucho@...kov.net,
        netdev@...r.kernel.org, rminnich@...dia.gov,
        syzkaller-bugs@...glegroups.com,
        v9fs-developer@...ts.sourceforge.net
Subject: BUG: unable to handle kernel paging request in kfree (2)

Hello,

syzbot found the following crash on:

HEAD commit:    ca04b3cca11a Merge tag 'armsoc-fixes' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=116d29b2400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=2ca6c7a31d407f86
dashboard link: https://syzkaller.appspot.com/bug?extid=ad37a4e3a54f2dbc5546
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=144c8162400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17daa6d0400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ad37a4e3a54f2dbc5546@...kaller.appspotmail.com

random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
BUG: unable to handle kernel paging request at ffffebe000000008
PGD 0 P4D 0
Oops: 0000 [#1] SMP KASAN
CPU: 1 PID: 4512 Comm: syz-executor551 Not tainted 4.18.0-rc3+ #137
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:virt_to_head_page include/linux/mm.h:638 [inline]
RIP: 0010:virt_to_cache mm/slab.c:399 [inline]
RIP: 0010:kfree+0xa0/0x260 mm/slab.c:3809
Code: 82 cb 01 00 00 48 ba 00 00 00 80 ff 77 00 00 48 01 c2 48 89 df 48 b8  
00 00 00 00 00 ea ff ff 48 c1 ea 0c 48 c1 e2 06 48 01 c2 <48> 8b 42 08 a8  
01 48 8d 48 ff 48 0f 45 d1 4c 8b 6a 18 49 63 75 74
RSP: 0018:ffff8801c9d0f520 EFLAGS: 00010086
RAX: ffffea0000000000 RBX: 0000000000000286 RCX: 0000000000000000
RDX: ffffebe000000000 RSI: 0000000000000000 RDI: 0000000000000286
RBP: ffff8801c9d0f540 R08: ffffed003b5e46d7 R09: ffffed003b5e46d6
R10: ffffed003b5e46d6 R11: ffff8801daf236b3 R12: 0000000000000286
R13: ffffffff8766d6c3 R14: ffff8801c9d0f690 R15: ffff8801af230380
FS:  00000000012d0880(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffebe000000008 CR3: 00000001aff92000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  p9_client_version net/9p/client.c:1009 [inline]
  p9_client_create+0xf43/0x16c9 net/9p/client.c:1069
  v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400
  v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135
  mount_fs+0xae/0x328 fs/super.c:1277
  vfs_kern_mount.part.34+0xdc/0x4e0 fs/namespace.c:1037
  vfs_kern_mount fs/namespace.c:1027 [inline]
  do_new_mount fs/namespace.c:2518 [inline]
  do_mount+0x581/0x30e0 fs/namespace.c:2848
  ksys_mount+0x12d/0x140 fs/namespace.c:3064
  __do_sys_mount fs/namespace.c:3078 [inline]
  __se_sys_mount fs/namespace.c:3075 [inline]
  __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075
  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4401d9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe6e8d4698 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401d9
RDX: 00000000200002c0 RSI: 00000000200001c0 RDI: 0000000000000000
RBP: 00000000006ca018 R08: 00000000200003c0 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000401a60
R13: 0000000000401af0 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
Dumping ftrace buffer:
    (ftrace buffer empty)
CR2: ffffebe000000008
---[ end trace a145a38935e2c7cf ]---
RIP: 0010:virt_to_head_page include/linux/mm.h:638 [inline]
RIP: 0010:virt_to_cache mm/slab.c:399 [inline]
RIP: 0010:kfree+0xa0/0x260 mm/slab.c:3809
Code: 82 cb 01 00 00 48 ba 00 00 00 80 ff 77 00 00 48 01 c2 48 89 df 48 b8  
00 00 00 00 00 ea ff ff 48 c1 ea 0c 48 c1 e2 06 48 01 c2 <48> 8b 42 08 a8  
01 48 8d 48 ff 48 0f 45 d1 4c 8b 6a 18 49 63 75 74
RSP: 0018:ffff8801c9d0f520 EFLAGS: 00010086
RAX: ffffea0000000000 RBX: 0000000000000286 RCX: 0000000000000000
RDX: ffffebe000000000 RSI: 0000000000000000 RDI: 0000000000000286
RBP: ffff8801c9d0f540 R08: ffffed003b5e46d7 R09: ffffed003b5e46d6
R10: ffffed003b5e46d6 R11: ffff8801daf236b3 R12: 0000000000000286
R13: ffffffff8766d6c3 R14: ffff8801c9d0f690 R15: ffff8801af230380
FS:  00000000012d0880(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffebe000000008 CR3: 00000001aff92000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
This bug is generated by a bot. It may contain errors.
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