Re[2]: [PATCH] firewire: net: fix panic in fwnet_write_complete

["Илья Басин" <basinilya@gmail.com>]

SR> Stefan Richter wrote:
>> My own testing on a dual core box --- peered with another Linux box
>> which ran the older eth1394 --- worked OK so far for transfers of
>> massive files (> 4 GiB) back and forth via FTP and ssh running on a text
>> console.
>> 
>> But in my first attempt to use FTP on X11 --- i.e. with more concurrent
>> interrupt sources --- the firewire-net box crashed very soon.  In that
>> test I used Dolphin of KDE as FTP client, and the crash already happened
>> after Dolphin had loaded and displayed the remote home directory and was
>> peeking into files for preview data.  I got the following trace:
>> 
>> ------------: cut here ]------------                  
>> kernel: BUG at mm/slab.c:2885!                        
SR> [...]
>> EIP: is at cache_free_debugcheck+0x1e8/0x2e8          
SR> [...]
>> Call: Trace:
>> ? __kfree_skb+0x6e/0x71
>> ? kmem_cache_free+0x56/0xb0
>> ? __kfree_skb+0x6e/0x71
>> ? kfree_skb+0x2b/0x2d
>> ? unix_stream_recvmsg+0x3c3/0x48d
>> ? file_read_actor+0x74/0xcc
>> ? sock_aio_read+0xf2/0x107
>> ? do_sync_read+0x89/0xc7

SR> Hi Илья,

SR> I am going to send a pull request for some other unrelated firewire
SR> fixes to Linus about tomorrow.

SR> firewire-net on the other hand needs still more work than my
SR> fwnet_write_complete patch since you and I now get these kmem cache
SR> corruption related bugs.

SR> What is your impression --- does this first incomplete fix decrease the
SR> likelihood of crashes enough to make it worth to include it in a pull
SR> request already?  I haven't done more extensive firewire-net tests since
SR> last week yet, hence it is hard to tell for me how severe the new issue
SR> is in practical use.

SR> (Also, I have no idea yet whether I will be quick or slow to find this
SR> other problem and whether it can be fixed in a manner that is suitable
SR> for a mainline merge before 2.6.33 is going to be released.)

Hi. Have just found 4 letters from you in gmail spam bin, including
this one. Your fix does decrease the chance of crash. Without the fix
crashes randomly occured within 3 minutes. With the fix - only after
10 minutes of copying. These 2 bugs are probably unrelated.

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