Messages in this thread | | | Date | Wed, 11 Jan 2017 13:00:24 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH v6] x86: fix kaslr and memmap collision |
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On Tue, 10 Jan 2017, Dave Jiang wrote: > +unsigned long simple_strtoul(const char *cp, char **endp, unsigned int base); > +long simple_strtol(const char *cp, char **endp, unsigned int base);
What are those functions for? They are not used in that patch at all.
> +static void mem_avoid_memmap(void) > +{ > + char arg[128]; > + int rc = 0;
What's the point of defining this variable here and zero initializing it?
> + /* see if we have any memmap areas */
Sentences start with an upper case letter. Everywhere!
> + if (cmdline_find_option("memmap", arg, sizeof(arg)) > 0) {
You can spare an indentation level by just returning when the search fails.
> + int i = 0; > + char *str = arg; > + > + while (str && (i < MAX_MEMMAP_REGIONS)) {
for (i = 0; str && (i < MAX_MEMMAP_REGIONS); i++) {
Please.
> + unsigned long long start, size; > + char *k = strchr(str, ','); > + > + if (k) > + *k++ = 0; > + > + rc = parse_memmap(str, &start, &size); > + if (rc < 0) > + break; > + str = k; > + /* a usable region that should not be skipped */ > + if (size == 0) > + continue; > + > + mem_avoid[MEM_AVOID_MEMMAP_BEGIN + i].start = start; > + mem_avoid[MEM_AVOID_MEMMAP_BEGIN + i].size = size;
So this makes no sense. You parse start/size as unsigned long long and then store it in an unsigned long. Works on 64bit, but on 32bit this is just wrong:
Assume a memmap above 4G, which then will create a avoid region below 4G due to truncation to unsigned long.
Thanks,
tglx
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