From mboxrd@z Thu Jan  1 00:00:00 1970
Mime-Version: 1.0 (Apple Message framework v612)
In-Reply-To: <fd5537fcee6a.fcee6afd5537@cwru.edu>
References: <fd5537fcee6a.fcee6afd5537@cwru.edu>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
Message-Id: <4F129E0C-7450-11D8-B24B-000A95D0C144@mightycheese.com>
Content-Transfer-Encoding: 7bit
From: Rob Pike <rob@mightycheese.com>
Subject: Re: [9fans] acme suicide
To: 9fans@cse.psu.edu
Date: Fri, 12 Mar 2004 10:08:48 -0800
Topicbox-Message-UUID: 2cf7763a-eacd-11e9-9e20-41e7f4b1d025

this is a stupid error. an assertion failure should be reduced to a  
warning.

/sys/src/cmd/acme/text.c:194,195 should be replaced by:

         if(t->ncache!=0 || t->file->b.nc || t->w==nil || t!=&t->w->body)
                 error("text.load");
         if(t->w->isdir && t->file->nname==0){
                 warning(nil, "empty directory name\n");
                 return 0;
         }

in short, move the check for empty directory name out of the test for  
error.

-rob

On Mar 9, 2004, at 5:48 AM, Noah Evans wrote:

> Awesome! another thing, have you ever tried to "Get" a nil string(when  
> you deleted the previous filename)? It's no biggie because I know to  
> avoid the error, but it might be interesting nevertheless.
>
> Noah
>
> acme: text.load: 'Del' file does not exist
> acme 5965: suicide: sys: trap: fault read addr=0x0 pc=0x0003aecd
>
> acid: stk()
> abort()+0x0 /sys/src/libc/9sys/abort.c:6
> error(s=0x4136c)+0x33 /sys/src/cmd/acme/util.c:55
> textload(t=0x82648,file=0x99d68,q0=0x0,setqid=0x1)+0x2c  
> /sys/src/cmd/acme/text.c:193
> get(et=0x8256c,flag1=0x1,t=0x82648,argt=0x0,arg=0x833de,narg=0x0)+0x1fe 
>  /sys/src/cmd/acme/exec.c:497
> execute(t=0x8256c,aq0=0xc,aq1=0xc,external=0x0,argt=0x0)+0x1ec  
> /sys/src/cmd/acme/exec.c:190
> mousethread()+0x49d /sys/src/cmd/acme/acme.c:550
> launcher386(arg=0x0,f=0x2276)+0x10 /sys/src/libthread/386.c:10
> 0xfefefefe ?file?:0
>
> ----- Original Message -----
> From: "rob pike, esq." <r@geekmail.cc>
> Date: Tuesday, March 9, 2004 0:28 am
> Subject: Re: [9fans] acme suicide
>
>>> I tried 'Edit , | man 2 9p' in the tag of an acme window and got:
>>>
>>> panic: D2B called on non-block 11a8c8 (double-free?)
>>> acme 1436: suicide: sys: trap: fault read addr=0x0 pc=0x0003aed5
>>
>> this is kind of amazing. i was testing something for rsc and
>> crashed acme.
>> tracked it down, fixed it.  it was a day 1 bug; amazing it had
>> never happened.
>> then i decided to track down your bug.  turns out it's the same thing.
>> amazing coincidence.
>>
>> here's the fix:
>>
>> r% yesterday -d /sys/src/cmd/acme/elog.c
>> diff /n/dump/2004/0308/sys/src/cmd/acme/elog.c
>> /sys/src/cmd/acme/elog.c173c173
>> < 	if(f->elog.type==Insert && q0==f->elog.q0 && (q0+nr)-f-
>>> elog.q0<Maxstring){---
>>> 	if(f->elog.type==Insert && q0==f->elog.q0 && f-
>>> elog.nr+nr<Maxstring){r%
>>
>> -rob
>>
>>