Re: Filesystem fuzzing

[Eric Sesterhenn <snakebyte@gmx.de>]

* Dave Kleikamp (shaggy@linux.vnet.ibm.com) wrote:
> > 
> > [52500.590030] ERROR: (device loop1): diRead: i_ino != di_number
> > [52500.590308] BUG: unable to handle kernel NULL pointer dereference at
> > 00000237
> > [52500.590518] IP: [<c019348a>] iput+0xa/0x50
> > [52500.590642] *pde = 00000000 
> > [52500.590749] Oops: 0000 [#2] PREEMPT DEBUG_PAGEALLOC
> > [52500.590958] Modules linked in: nfsd exportfs
> > [52500.591155] 
> > [52500.591220] Pid: 6938, comm: mount Tainted: G      D   (2.6.26-rc3
> > #26)
> > [52500.591304] EIP: 0060:[<c019348a>] EFLAGS: 00010282 CPU: 0
> > [52500.591356] EIP is at iput+0xa/0x50
> > [52500.591356] EAX: fffffffb EBX: fffffffb ECX: 00000001 EDX: 00000000
> > [52500.591356] ESI: c9811920 EDI: cbd5f780 EBP: cbc67e34 ESP: cbc67e30
> > [52500.591356]  DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
> > [52500.591356] Process mount (pid: 6938, ti=cbc67000 task=cbeb3f00
> > task.ti=cbc67000)
> > [52500.591356] Stack: fffffffb cbc67e5c c0316078 cbc67e4c fffffffb
> > 00000000 00000000 00000002 
> > [52500.591356]        00000000 c9811920 00000000 cbc67ea0 c01827ff
> > cf415d40 c07b93c0 cf415d40 
> > [52500.591356]        c9811920 706f6f6c 00000031 c01971ed c07e4ddc
> > c01971ed 000000d0 cf32e6c0 
> > [52500.591356] Call Trace:
> > [52500.591356]  [<c0316078>] ? jfs_fill_super+0x268/0x2a0
> > [52500.591356]  [<c01827ff>] ? get_sb_bdev+0xef/0x120
> > [52500.591356]  [<c01971ed>] ? alloc_vfsmnt+0xdd/0x120
> > [52500.591356]  [<c01971ed>] ? alloc_vfsmnt+0xdd/0x120
> > [52500.591356]  [<c0314fd2>] ? jfs_get_sb+0x22/0x30
> > [52500.591356]  [<c0315e10>] ? jfs_fill_super+0x0/0x2a0
> > [52500.591356]  [<c018234a>] ? vfs_kern_mount+0x3a/0x90
> > [52500.591356]  [<c01823f9>] ? do_kern_mount+0x39/0xd0
> > [52500.591356]  [<c0198425>] ? do_new_mount+0x65/0x90
> > [52500.591356]  [<c01985aa>] ? do_mount+0x15a/0x1b0
> > [52500.591356]  [<c015fc7b>] ? __get_free_pages+0x1b/0x30
> > [52500.591356]  [<c01962b8>] ? copy_mount_options+0x38/0x140
> > [52500.591356]  [<c0188d47>] ? getname+0xa7/0xc0
> > [52500.591356]  [<c019866f>] ? sys_mount+0x6f/0xb0
> > [52500.591356]  [<c0103d7d>] ? sysenter_past_esp+0x6a/0xb1
> > [52500.591356]  =======================
> > [52500.591356] Code: 4f fa ff 5d c3 8d b6 00 00 00 00 8d bf 00 00 00 00
> > 55 89 e5 e8 d8 88 46 00 31 c0 5d c3 8d 74 26 00 55 85 c0 89 e5 53 89 c3
> > 74 3d <83> b8 3c 02 00 00 40 74 37 8d 40 24 ba e0 ce 7a c0 e8 90 3c 1d 
> > [52500.591356] EIP: [<c019348a>] iput+0xa/0x50 SS:ESP 0068:cbc67e30
> > [52500.599040] ---[ end trace 299f5ea1b691e69f ]---
> > 
> > kerneloops.org also catched it, but the code is not disassembled
> > yet, http://kerneloops.org/raw.php?rawid=13020&msgid=
> > this is with linux-next from yesterday
> > 
> > A copy of the image file is available here:
> > http://www.cccmz.de/~snakebyte/jfs.7.img.bz2
> 
> Thanks.  It's a bug in an error path that hadn't been caught before.
> This patch should fix it.

with this patch i cant reproduce this, i can confirm that this does
fix the issue

greetings, Eric