Re: bugs in trap signal handling

[Tinni]

Chet Ramey wrote:
> 
> On 10/10/12 2:53 AM, lanshun zhou wrote:
>> Red Hat Enterprise Linux Server release 6.2 (Santiago)
>> uname -r:       2.6.32-220.17.1.el6.x86_64
>> bash version: bash-4.1.2-9.el6_2.src.rpm  (also tested with bash-4.2
>> compiled from source
>> with patches bash42-001~bash42-037)
>> 
>> When interrupt_immediately is set, handler for signals registered by trap
>> is called
>> immediately after the signal is triggered. But many function calls in
>> trap_handler
>> are not async-signal-safe, so it's unsafe and could cause bash to enter
>> a deadlock.
> 
> Thanks for the report.  This has been under discussion for a long time.
> 
> There are a couple of issues: how one satisfies users' expections of
> responsiveness, and what to do with partially-read input.  The work on
> that continues.
> 
> Right now, I've been running a slightly modified version of your script
> (I changed the echo -n ? to echo ? to avoid stdio buffering issues) for
> over an hour on a RHEL5 system without any lockups.  I have ideas about
> what to do to reduce the potential deadlock window, but I need a way to
> measure the effect of those changes.
> 
> Chet
> 
> -- 
> ``The lyf so short, the craft so long to lerne.'' - Chaucer
>                ``Ars longa, vita brevis'' - Hippocrates
> Chet Ramey, ITS, CWRU    chet@case.edu   
> http://cnswww.cns.cwru.edu/~chet/
> 
> 
> 

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