Re: kprobe fault handling

[Martin Hunt <hunt@redhat.com>]

[-- Attachment #1: Type: text/plain, Size: 408 bytes --]

Maybe I should post one of my test programs. The attached one crashes on
my i686 system running an SMP kernel in a couple of seconds. On non-SMP
kernels, it prints a bunch of junk to syslog but doesn't seem to crash,
although I haven't tested it much.  With my simple fixup_exception patch
to the handler, it runs perfectly. I've modified it to keep looping
through the address space and run it for hours.



[-- Attachment #2: mem_test.stp --]
[-- Type: text/plain, Size: 619 bytes --]

# Memory test. Tries userspace copies covering
# the entire 32-bit address space.

global addr

%{
	static char buf[16384];
%}

function copy_more:long(addr:long)
%{
      THIS->__retvalue = _stp_copy_from_user (buf, 
	(char __user *)(long)THIS->addr, 2048);
%}

probe kernel.function("sys_read") {
	printf("copying from %x ... ", addr)
	ret = copy_more(addr)
	if (ret < 2048)
		printf("FAILED (%d)\n", ret)
	else
		printf("GOOD\n")
	addr += 4096
	if (addr > 0xffffffff)
		exit()
}

probe end {
	printf("\nDONE. Test succeeded if you see this and there\n")
	printf("are no might_sleep warnings in the system log.\n")
}