Messages in this thread Patch in this message | | | Subject | Re: [PATCH*] show last kernel-image symbol in /proc/kallsyms | From | Rusty Russell <> | Date | Mon, 10 May 2004 14:14:10 +1000 |
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On Mon, 2004-05-10 at 10:14, Randy.Dunlap wrote: > 'cat' or 'tail' of /proc/kallsyms (2.6.6-rc2 or -rc3, & probably much > earlier) does not include the last kernel-image symbol (_einittext). > > _einittext is the last symbol generated in .tmp_kallsyms2.S > and the symbol count in that file also appears to be correct, > but the iterator code for /proc/kallsyms comes up 1 short somehow. > > Here are 2 patches. Either one of them "fixes" the problem. > Neither of them is the correct fix AFAIK.
Ah, I see you are a student of the Morton school of patch extraction. Well, it worked.
Name: Show Last Symbol in /proc/kallsyms Status: Tested on 2.6.6-rc3.bk11
The current code doesn't show the last symbol (usually _einittext) in /proc/kallsyms. The reason for this is subtle: s_start() returns an empty string for position 0 (ignored by s_show()), and s_next() returns the first symbol for position 1.
What should happen is that update_iter() for position 0 should fill in the first symbol. Unfortunately, the get_ksymbol_core() fills in the symbol information, *and* updates the iterator: we have to split these functions, which we do by making it return the length of the name offset.
Then we can call get_ksymbol_core() without moving the iterator, meaning that we can call it at position 0 (ie. s_start()).
diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.6.6-rc3-bk11/kernel/kallsyms.c working-2.6.6-rc3-bk11/kernel/kallsyms.c --- linux-2.6.6-rc3-bk11/kernel/kallsyms.c 2004-03-12 07:57:28.000000000 +1100 +++ working-2.6.6-rc3-bk11/kernel/kallsyms.c 2004-05-10 13:11:06.000000000 +1000 @@ -171,21 +171,23 @@ static int get_ksymbol_mod(struct kallsy return 1; } -static void get_ksymbol_core(struct kallsym_iter *iter) +/* Returns space to next name. */ +static unsigned long get_ksymbol_core(struct kallsym_iter *iter) { - unsigned stemlen; + unsigned stemlen, off = iter->nameoff; /* First char of each symbol name indicates prefix length shared with previous name (stem compression). */ - stemlen = kallsyms_names[iter->nameoff++]; + stemlen = kallsyms_names[off++]; - strlcpy(iter->name+stemlen, kallsyms_names+iter->nameoff, 128-stemlen); - iter->nameoff += strlen(kallsyms_names + iter->nameoff) + 1; + strlcpy(iter->name+stemlen, kallsyms_names + off, 128-stemlen); + off += strlen(kallsyms_names + off) + 1; iter->owner = NULL; iter->value = kallsyms_addresses[iter->pos]; iter->type = 't'; upcase_if_global(iter); + return off - iter->nameoff; } static void reset_iter(struct kallsym_iter *iter) @@ -210,16 +212,16 @@ static int update_iter(struct kallsym_it /* We need to iterate through the previous symbols: can be slow */ for (; iter->pos != pos; iter->pos++) { - get_ksymbol_core(iter); + iter->nameoff += get_ksymbol_core(iter); cond_resched(); } + get_ksymbol_core(iter); return 1; }
-- Anyone who quotes me in their signature is an idiot -- Rusty Russell
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