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From: Tom Talpey <tom@talpey.com>
To: David Howells <dhowells@redhat.com>, Steve French <smfrench@gmail.com>
Cc: Steve French <sfrench@samba.org>,
	Shyam Prasad N <nspmangalore@gmail.com>,
	Rohith Surabattula <rohiths.msft@gmail.com>,
	Long Li <longli@microsoft.com>,
	Namjae Jeon <linkinjeon@kernel.org>,
	Stefan Metzmacher <metze@samba.org>,
	Jeff Layton <jlayton@kernel.org>,
	linux-cifs@vger.kernel.org
Subject: Re: pcap of misbehaving fallocate over cifs rdma
Date: Thu, 26 Jan 2023 15:29:25 -0500	[thread overview]
Message-ID: <104c2782-4d9a-22ce-d680-08d01733fb4e@talpey.com> (raw)
In-Reply-To: <2896646.1674762874@warthog.procyon.org.uk>

On 1/26/2023 2:54 PM, David Howells wrote:
> Steve French <smfrench@gmail.com> wrote:
> 
>> I am puzzled ... you show the fallocate failing but why do you mention
>> it sending data, sending writes
> 
> smb3_simple_fallocate_write_range() sends data.
> 
>> - when I try the fallocate you pasted above I see what is in the attached
>> screenshot go over the network (no writes) - and your example looks like it
>> simply doesn't send anything then resets the session at frame 93
> 
> Look at frame 92.  That's the concluding packet of the write performed by
> smb3_simple_fallocate_write_range().
> 
>    74 4.568861795  192.168.6.2 -> 192.168.6.1  SMB2 250 Ioctl Request FSCTL_QUERY_ALLOCATED_RANGES File: hello
>     75 4.569429926  192.168.6.1 -> 192.168.6.2  SMB2 242 Ioctl Response FSCTL_QUERY_ALLOCATED_RANGES
>     77 4.680495774  192.168.6.2 -> 192.168.6.1  DDP/RDMA 1514 50018 > 5445 Send [more DDP segments]
>     78 4.680496219  192.168.6.2 -> 192.168.6.1  DDP/RDMA 1514 50018 > 5445 Send [more DDP segments]
>     79 4.680496364  192.168.6.2 -> 192.168.6.1  DDP/RDMA 1514 50018 > 5445 Send [more DDP segments]
>     80 4.680496552  192.168.6.2 -> 192.168.6.1  DDP/RDMA 1514 50018 > 5445 Send [more DDP segments]
>     81 4.680496698  192.168.6.2 -> 192.168.6.1  DDP/RDMA 1514 50018 > 5445 Send [more DDP segments]
>     82 4.680496844  192.168.6.2 -> 192.168.6.1  DDP/RDMA 1514 50018 > 5445 Send [more DDP segments]
>     83 4.680496989  192.168.6.2 -> 192.168.6.1  DDP/RDMA 1514 50018 > 5445 Send [more DDP segments]
>     84 4.680497177  192.168.6.2 -> 192.168.6.1  DDP/RDMA 1514 50018 > 5445 Send [more DDP segments]
>     88 4.680638842  192.168.6.2 -> 192.168.6.1  DDP/RDMA 1514 50018 > 5445 Send [more DDP segments]
>     89 4.680639016  192.168.6.2 -> 192.168.6.1  DDP/RDMA 1514 50018 > 5445 Send [more DDP segments]
>     90 4.680704523  192.168.6.1 -> 192.168.6.2  DDP/RDMA 114 5445 > 50018 Terminate [last DDP segment]
>     91 4.680735089  192.168.6.2 -> 192.168.6.1  DDP/RDMA 1514 50018 > 5445 Send [more DDP segments]
>     92 4.680735359  192.168.6.2 -> 192.168.6.1  SMB2 946 Write Request Len:16384 Off:204800 File: hello
> 

That's a really large SMBDirect Send operation, it looks like it's
trying to send the entire write in one message and it overflows
the receive buffer.

I'm still fighting with wireshark and can't decode the layers
above TCP. Can you look at the SMBDirect negotiation at the
start of the trace, and tell me what the max send/receive
values were set by each side?

  reply	other threads:[~2023-01-26 20:29 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-24 17:48 cifs-rdma: KASAN-detected UAF when using rxe driver David Howells
2023-01-25  7:48 ` David Howells
2023-01-25 14:02 ` [PATCH] cifs: Fix oops due to uncleared server->smbd_conn in reconnect David Howells
2023-01-25 14:47   ` Tom Talpey
2023-01-25 15:52   ` Tom Talpey
2023-01-25 16:20   ` Steve French
2023-01-25 20:41   ` David Howells
2023-01-25 22:24     ` Tom Talpey
2023-01-25 22:43     ` David Howells
2023-01-25 22:56       ` Tom Talpey
2023-01-25 23:42       ` Namjae Jeon
2023-01-26 14:42       ` pcap of misbehaving fallocate over cifs rdma David Howells
2023-01-26 19:54         ` David Howells
2023-01-26 20:29           ` Tom Talpey [this message]
2023-01-26 20:47           ` David Howells
2023-01-26 15:20   ` [PATCH] cifs: Fix oops due to uncleared server->smbd_conn in reconnect David Howells
2023-01-26 19:22     ` Tom Talpey
2023-01-26 19:49     ` David Howells

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