smbfs and Slab corruption bug in 2.6

smbfs and Slab corruption bug in 2.6

[Stas Sergeev]

Hello.

When I am trying to access some files
on an SMB server, I get this in the log:

---
Oct 25 09:30:09 stas mount.smbfs[2086]:   tdb(/var/lib/samba/gencache.tdb): tdb_lock failed on list 60 ltype=1 (Bad file descriptor)
Oct 25 09:30:39 stas kernel: smb_add_request: request [d242b03c, mid=1802201963] timed out!
Oct 25 09:30:39 stas kernel: Slab corruption: start=d242b03c, len=252
Oct 25 09:30:39 stas kernel: Redzone: 0x5a2cf071/0x5a2cf071.
Oct 25 09:30:39 stas kernel: Last user: [<e08ef84a>](smb_add_request+0x2aa/0x310 [smbfs])
Oct 25 09:30:39 stas kernel: 000: 6b 6b 6b 6b 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b
Oct 25 09:30:39 stas kernel: 0f0: 6b 6b 6b 6b 02 00 58 00 fb ff ff ff
Oct 25 09:30:39 stas kernel: Next obj: start=d242b144, len=252
Oct 25 09:30:39 stas kernel: Redzone: 0x170fc2a5/0x170fc2a5.
Oct 25 09:30:39 stas kernel: Last user: [<e08ef1d4>](smb_do_alloc_request+0x24/0xa0 [smbfs])
Oct 25 09:30:39 stas kernel: 000: 4c b2 42 d2 74 27 a6 de 02 00 00 00 01 00 00 00
Oct 25 09:30:39 stas kernel: 010: ad 4e ad de 3c 8d 09 d4 3c 8d 09 d4 00 40 00 00
Oct 25 09:30:39 stas kernel: smb_add_request: request [d242beac, mid=1802201963] timed out!
Oct 25 09:30:39 stas kernel: Slab corruption: start=d242beac, len=252
Oct 25 09:30:39 stas kernel: Redzone: 0x5a2cf071/0x5a2cf071.
Oct 25 09:30:39 stas kernel: Last user: [<e08ef84a>](smb_add_request+0x2aa/0x310 [smbfs])
Oct 25 09:30:39 stas kernel: 000: 6b 6b 6b 6b 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b
Oct 25 09:30:39 stas kernel: 0f0: 6b 6b 6b 6b 02 00 58 00 fb ff ff ff
Oct 25 09:30:39 stas kernel: Prev obj: start=d242bda4, len=252
Oct 25 09:30:39 stas kernel: Redzone: 0x5a2cf071/0x5a2cf071.
Oct 25 09:30:39 stas kernel: Last user: [<00000000>](0x0)
Oct 25 09:30:39 stas kernel: 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Oct 25 09:30:39 stas kernel: 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
Oct 25 09:30:39 stas kernel: smb_add_request: request [d242b144, mid=62] timed out!
Oct 25 09:30:40 stas kernel: smb_lookup: find images/money.jpg failed, error=-5
Oct 25 09:30:40 stas kernel: smb_add_request: request [d242b24c, mid=63] timed out!
---
and then the system is unstable, so that
I have to reboot.

This happens with all 2.6 kernels I tried
(from something like 2.6.2 to 2.6.9).
The only reference to the similar problem
I can find, is this:
http://lkml.org/lkml/2003/5/22/49

This bug is really nasty and I guess I was
waiting for too long for it to get fixed.
Any hints how can I get more info out of
it, or how can I start debugging it?

Re: smbfs and Slab corruption bug in 2.6

[Andrew Morton]

Stas Sergeev <stsp@aknet.ru> wrote:
>
> Hello.
> 
> When I am trying to access some files
> on an SMB server, I get this in the log:

smb_add_request() does:

		if (!(req->rq_flags & SMB_REQ_RECEIVED)) {
			list_del_init(&req->rq_queue);
			smb_rput(req);
		}

but then proceeds to play with *req.

Urban, do you have time to review the code in there?

Thanks.

> ---
> Oct 25 09:30:09 stas mount.smbfs[2086]:   tdb(/var/lib/samba/gencache.tdb): tdb_lock failed on list 60 ltype=1 (Bad file descriptor)
> Oct 25 09:30:39 stas kernel: smb_add_request: request [d242b03c, mid=1802201963] timed out!
> Oct 25 09:30:39 stas kernel: Slab corruption: start=d242b03c, len=252
> Oct 25 09:30:39 stas kernel: Redzone: 0x5a2cf071/0x5a2cf071.
> Oct 25 09:30:39 stas kernel: Last user: [<e08ef84a>](smb_add_request+0x2aa/0x310 [smbfs])
> Oct 25 09:30:39 stas kernel: 000: 6b 6b 6b 6b 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b
> Oct 25 09:30:39 stas kernel: 0f0: 6b 6b 6b 6b 02 00 58 00 fb ff ff ff
> Oct 25 09:30:39 stas kernel: Next obj: start=d242b144, len=252
> Oct 25 09:30:39 stas kernel: Redzone: 0x170fc2a5/0x170fc2a5.
> Oct 25 09:30:39 stas kernel: Last user: [<e08ef1d4>](smb_do_alloc_request+0x24/0xa0 [smbfs])
> Oct 25 09:30:39 stas kernel: 000: 4c b2 42 d2 74 27 a6 de 02 00 00 00 01 00 00 00
> Oct 25 09:30:39 stas kernel: 010: ad 4e ad de 3c 8d 09 d4 3c 8d 09 d4 00 40 00 00
> Oct 25 09:30:39 stas kernel: smb_add_request: request [d242beac, mid=1802201963] timed out!
> Oct 25 09:30:39 stas kernel: Slab corruption: start=d242beac, len=252
> Oct 25 09:30:39 stas kernel: Redzone: 0x5a2cf071/0x5a2cf071.
> Oct 25 09:30:39 stas kernel: Last user: [<e08ef84a>](smb_add_request+0x2aa/0x310 [smbfs])
> Oct 25 09:30:39 stas kernel: 000: 6b 6b 6b 6b 6b 6b 6b 6b 6a 6b 6b 6b 6b 6b 6b 6b
> Oct 25 09:30:39 stas kernel: 0f0: 6b 6b 6b 6b 02 00 58 00 fb ff ff ff
> Oct 25 09:30:39 stas kernel: Prev obj: start=d242bda4, len=252
> Oct 25 09:30:39 stas kernel: Redzone: 0x5a2cf071/0x5a2cf071.
> Oct 25 09:30:39 stas kernel: Last user: [<00000000>](0x0)
> Oct 25 09:30:39 stas kernel: 000: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
> Oct 25 09:30:39 stas kernel: 010: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
> Oct 25 09:30:39 stas kernel: smb_add_request: request [d242b144, mid=62] timed out!
> Oct 25 09:30:40 stas kernel: smb_lookup: find images/money.jpg failed, error=-5
> Oct 25 09:30:40 stas kernel: smb_add_request: request [d242b24c, mid=63] timed out!
> ---
> and then the system is unstable, so that
> I have to reboot.
> 
> This happens with all 2.6 kernels I tried
> (from something like 2.6.2 to 2.6.9).
> The only reference to the similar problem
> I can find, is this:
> http://lkml.org/lkml/2003/5/22/49
> 
> This bug is really nasty and I guess I was
> waiting for too long for it to get fixed.
> Any hints how can I get more info out of
> it, or how can I start debugging it?
> 
> -
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