Re: [PATCH] -o intr mount option prevents core dumps on 2.4 kernel

[Steve Dickson <SteveD@redhat.com>]

Trond Myklebust wrote:

>on den 12.01.2005 Klokka 14:11 (-0500) skreiv Steve Dickson:
>
>  
>
>>Here is what I found.... just adding the PF_DUMPCORE rpc_clnt_sigmask() 
>>no core was dropped
>>because __rpc_execute returned -ERESTARTSYS due to signalled() == TRUE.
>>
>>When I added back the  PF_DUMPCORE check to __rpc_execute(), only the 
>>header of the core
>>was dropped  because nfs_wait_event() returned -ERESTARTSYS because 
>>signalled() == TRUE.
>>
>>When I added back the PF_DUMPCORE to nfs_wait_event(), the entire core 
>>was dropped.
>>
>>So it appears to me that you need both checks.....
>>    
>>
>
>No! Those extra checks are neither necessary, nor are they even correct!
>I repeat what I said in my earlier mail:
>
>        - The change to nfs_wait_event() converts it into an
>        unconditional uninterruptible sleep. That means you can never
>        "kill -9" out of waiting for the core dump to finish in case the
>        server crashes!
>  
>
By adding the PF_DUMPCORE check to rpc_clnt_sigmask() (as you suggested)
I thought I had taken care of this problem... but now I realize the 
check in nfs_wait_event()
is the real issue... sorry for making you swing that clue bat twice!! :)

>        - The loop you add to __rpc_execute() is pointless: The signal
>        that caused your process to wake up is neither cleared nor
>        masked, so when it later tries to block (such as when waiting
>        for a reply from the server), that process will just find itself
>        immediately woken up again by the same signal.
>  
>
I do understand this point.... and I *thought* I had addressed it by 
making __rpc_execute()
temporary ignoring  signals and having nfs_wait_event () call  
wait_event() instead
of  wait_event_interruptible().....


>As for myself, I'm getting full coredumps when I apply the 2 line patch
>I sent you. The appended testcase works every time:
>  
>
hmm.... something is amiss.... because I'm definitely not see this.... 
but I'll keep digging...

thanks!

steved.






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