Hi, On Fri, Feb 19, 2016 at 05:47:40PM +0530, haris iqbal wrote: > Hello. > > I was going through the code of strace.c, when I found this line in > init() function. > > tcbtabsize = argc; /* Surely enough for all -p args. */
> That set me thinking is it really is what I think it is. Can it really > be that strace will allocate that many tcbtab pointers and tcp > structures as many arguments I give to the program. The fun of the situation is that after commit v4.6-258-ge8172b7 this is no longer enough for all -p args. > So I set out to find out whether there is a way to make strace take a > lot of memory, without actually using it. > > Firstly I found out that if there is a way to give large number of > arguments and still make strace work as it should. It turns out that > there is. One can give as many -i (or some other such arguments) as > arguments and the strace would work properly. > > Then, I wanted to make sure whether the code is actually allocating > that many resources as as there are arguments. So I went into the > cleanup() function that is called through error_msg_and_die(). And > there I added debugging code to see how many of them were actually > allocated. It turns out that they were allocated. > I added a print statement in the for loop of cleanup(). It ran for as > many number of times as there were arguments. Although the usefull one > was the first one only, which had the pid of the process being traced > (strace was run with -p <pid> option). > > So, summing it all up. I ran a script which gave strace a -p option > and a process pid to trace. Along with that some 600000 -i options. It > ran successfully with a memory consumption of around 100mb. Thats a > lot for a small system with limited memory. OK, so what would you suggest to change in initial tcb table allocation? -- ldv
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