Date: Thu, 30 Jan 1997 06:11:38 +1100 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, swallace@ece.uci.edu Cc: cvs-all@freefall.freebsd.org, CVS-committers@freefall.freebsd.org, cvs-sys@freefall.freebsd.org, dyson@freebsd.org, jkh@freefall.freebsd.org Subject: Re: cvs commit: src/sys/i386/linux imgact_linux.c Message-ID: <199701291911.GAA10699@godzilla.zeta.org.au>
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>>> Modified: sys/i386/linux imgact_linux.c
>>> Log:
>>> *Ahem* - opt_rlimit.h does not exist in the LKM case. This was another
>>> 2.2 build-breaker.. :(
>> ...
>> The correct fix seems to be particularly easy in this case. Old code:
>> ...
>> Just remove the bogus check against MAXDSIZ. The correct limit (rlim_cur)
>> is already checked. rlim_cur <= MAXDSIZ, so checking against MAXDSIZ is
>> currently a no-op.
>Bruce, no one has done anything about this "wrong" fix of Jordan's.
>Do you want to implement your idea? It's still in 2.2R.
I just fixed it locally. Since it's cosmetic, I won't commit it for a
while.
imgact_aout.c and imgact_gzip.c also do the unnecssary check and have to
include the options file for it. Fixed.
I noticed several related non-cosmetic problems:
- imgact_elf.c and imgact_coff.c don't seem to limit the text or data
sections at all. An executable with a too-large data section will
probably crash early when it tries to extend the break.
- the text limit of MAXTSIZ is not configurable either statically or
with setrlimit(). It's default of 16M is rather small. It seems to
be only used in imgact_aout.c and imgact_aout.c. More executable
pages can be allocated using mmap().
- mmap() doesn't honor the data limit either. The only effective memory
limits are the RSS limit and the size of swap. This is demonstrated
by the enclosed program. It uses all of swap. read-only and
MAP_SHARED variations of it demonstrate panics and nfs paging bugs.
BTW, how do you generate files from the linux syscalls.master? There
should be a makefile as in /sys/kern.
Bruce
#include <sys/types.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <stdio.h>
int main(void)
{
int fd, i;
caddr_t p;
fd = open("zz", O_RDWR);
if (fd == -1)
perror("open");
while (1) {
p = mmap(NULL, 128 * 4096, PROT_READ | PROT_WRITE, MAP_PRIVATE,
fd, (off_t)0);
if (p == MAP_FAILED)
perror("mmap");
printf("%p %p\n", sbrk(0), p);
for (i = 0; i < 128 * 4096; i += 4096)
*(volatile int *)((char *)p + i) = 1;
}
}
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