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Ktr(9) stores format string and arguments in the event circular buffer,

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not the string formatted at the time of CTRX() call. Stack_ktr(9) uses
an on-stack buffer for the symbol name, that is supplied as an argument
to ktr. As result, stack_ktr() traces show garbage or cause page faults.

Fix stack_ktr() by using pointer to module symbol table that is supposed
to have a longer lifetime.

Tested by:	pho
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2008-10-19 11:13:49 +00:00
parent 59f0ec8329
commit ea797aaed5
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=184060
1 changed files with 24 additions and 20 deletions
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44
sys/kern/subr_stack.c
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@ -45,8 +45,7 @@ static MALLOC_DEFINE(M_STACK, "stack", "Stack Traces");
static void stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen,
long *offset);
#ifdef DDB
static void stack_symbol_ddb(vm_offset_t pc, char *namebuf, u_int buflen,
long *offset);
static void stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset);
#endif
struct stack *
@ -109,16 +108,15 @@ stack_print(struct stack *st)
void
stack_print_ddb(struct stack *st)
{
char namebuf[64];
const char *name;
long offset;
int i;
KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
for (i = 0; i < st->depth; i++) {
stack_symbol_ddb(st->pcs[i], namebuf, sizeof(namebuf),
&offset);
stack_symbol_ddb(st->pcs[i], &name, &offset);
printf("#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
namebuf, offset);
name, offset);
}
}
#endif
@ -146,16 +144,15 @@ stack_sbuf_print(struct sbuf *sb, struct stack *st)
void
stack_sbuf_print_ddb(struct sbuf *sb, struct stack *st)
{
char namebuf[64];
const char *name;
long offset;
int i;
KASSERT(st->depth <= STACK_MAX, ("bogus stack"));
for (i = 0; i < st->depth; i++) {
stack_symbol_ddb(st->pcs[i], namebuf, sizeof(namebuf),
&offset);
stack_symbol_ddb(st->pcs[i], &name, &offset);
sbuf_printf(sb, "#%d %p at %s+%#lx\n", i, (void *)st->pcs[i],
namebuf, offset);
name, offset);
}
}
@ -164,7 +161,7 @@ void
stack_ktr(u_int mask, const char *file, int line, struct stack *st, u_int depth,
int cheap)
{
char namebuf[64];
const char *name;
long offset;
int i;
@ -187,10 +184,9 @@ stack_ktr(u_int mask, const char *file, int line, struct stack *st, u_int depth,
if (depth == 0 || st->depth < depth)
depth = st->depth;
for (i = 0; i < depth; i++) {
stack_symbol_ddb(st->pcs[i], namebuf,
sizeof(namebuf), &offset);
stack_symbol_ddb(st->pcs[i], &name, &offset);
ktr_tracepoint(mask, file, line, "#%d %p at %s+%#lx",
i, st->pcs[i], (u_long)namebuf, offset, 0, 0);
i, st->pcs[i], (u_long)name, offset, 0, 0);
}
}
}
@ -214,13 +210,21 @@ stack_symbol(vm_offset_t pc, char *namebuf, u_int buflen, long *offset)
#ifdef DDB
static void
stack_symbol_ddb(vm_offset_t pc, char *namebuf, u_int buflen, long *offset)
stack_symbol_ddb(vm_offset_t pc, const char **name, long *offset)
{
linker_symval_t symval;
c_linker_sym_t sym;
if (linker_ddb_search_symbol_name((caddr_t)pc, namebuf, buflen,
offset) != 0) {
*offset = 0;
strlcpy(namebuf, "??", buflen);
};
if (linker_ddb_search_symbol((caddr_t)pc, &sym, offset) != 0)
goto out;
if (linker_ddb_symbol_values(sym, &symval) != 0)
goto out;
if (symval.name != NULL) {
*name = symval.name;
return;
}
out:
*offset = 0;
*name = "??";
}
#endif