On Thu, 15 May 2008, Cyrill Gorcunov wrote:
[Andrew Morton - Thu, May 15, 2008 at 10:58:03AM -0700]
| On Wed, 14 May 2008 19:44:02 +0400 Cyrill Gorcunov <gorcunov@xxxxxxxxx> wrote:
|
| > This patch does fix build bug on m68k wich does not have strncat in straight way.
| >
| > What is more important - my previous patch
| >
| > commit e662e1cfd434aa234b72fbc781f1d70211cb785b
| > Author: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
| > Date: Mon May 12 14:02:22 2008 -0700
| >
| > init: don't lose initcall return values
| >
| > has introduced potential buffer overflow by wrong calculation
| > of string accumulator size.
| >
| > Many thanks Andreas Schwab and Geert Uytterhoeven for helping
| > to catch and fix the bug.
| >
| > Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
| > ---
| >
| > Index: linux-2.6.git/init/main.c
| > ===================================================================
| > --- linux-2.6.git.orig/init/main.c 2008-05-14 17:55:10.000000000 +0400
| > +++ linux-2.6.git/init/main.c 2008-05-14 19:11:18.000000000 +0400
| > @@ -702,7 +702,7 @@ static void __init do_initcalls(void)
| >
| > for (call = __initcall_start; call < __initcall_end; call++) {
| > ktime_t t0, t1, delta;
| > - char msgbuf[40];
| > + char msgbuf[64];
| > int result;
| >
| > if (initcall_debug) {
| > @@ -729,11 +729,11 @@ static void __init do_initcalls(void)
| > sprintf(msgbuf, "error code %d ", result);
| >
| > if (preempt_count() != count) {
| > - strncat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
| > + strcat(msgbuf, "preemption imbalance ");
| > preempt_count() = count;
| > }
| > if (irqs_disabled()) {
| > - strncat(msgbuf, "disabled interrupts ", sizeof(msgbuf));
| > + strcat(msgbuf, "disabled interrupts ");
| > local_irq_enable();
| > }
| > if (msgbuf[0]) {
|
| umm, why can't m68k call strncat() from init/main.c??
|
there some problem with headers iirc, we have to declare it first or
use some gcc option (as Adrian suggested). Actually I would prefer to use
gcc turns the strncat() into an implicit call to strlen() and some form
of expanded memcpy(). E.g.
if (preempt_count() != count) {
strncat(msgbuf, "preemption imbalance ", sizeof(msgbuf));
preempt_count() = count;
}
becomes
cmp.l 884(%a2),%d6 | <variable>.thread.info.preempt_count, count
jeq .L61 |
move.l %d7,-(%sp) | tmp76,
jbsr strlen |
addq.l #4,%sp |,
move.l %d7,%a0 | tmp76, tmp80
add.l %d0,%a0 |, tmp80
move.l #1886545253,(%a0)+ |,
move.l #1836086377,(%a0)+ |,
move.l #1869488233,(%a0)+ |,
move.l #1835164012,(%a0)+ |,
move.l #1634624357,(%a0)+ |,
move.w #8192,(%a0) |,* D.28541
move.l %d6,884(%a2) | count, <variable>.thread.info.preempt_count
.L61:
All other explicit calls to strlen() are inlined, as per
include/asm-m68k/string.h.
strlcat there but it seems it would fail to build too. Originally I've messed
strlcat with strncat :(
Actually it build and runs fine after s/strncat/strlcat/...
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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