Don't use kmalloc in get_fn_name()
Back in commit 290962da6e27 ("Reflects symbol table into the kernel"), we
changed from using the old debuginfo to a autogenerated table of strings.
Those new strings are null-terminated. The old debuginfo wasn't.
get_fn_name() needed to add the trailing \0, but we don't need to anymore.
The end result is that debug code that looks up a function name for a given
symbol, such as backtrace(), won't need to kmalloc. This will help when we
are trying to backtrace failures in the allocator.
Signed-off-by: Barret Rhoden <brho@cs.berkeley.edu>
diff --git a/kern/include/kdebug.h b/kern/include/kdebug.h
index f8744c1..7b482aa 100644
--- a/kern/include/kdebug.h
+++ b/kern/include/kdebug.h
@@ -7,7 +7,7 @@
/* for includes */ struct proc;
struct symtab_entry {
- char *name;
+ const char *name;
uintptr_t addr;
};
@@ -49,8 +49,8 @@
static inline uintptr_t get_caller_pc(void);
/* Returns a null-terminated string with the function name for a given PC /
- * instruction pointer. kfree() the result. */
-char *get_fn_name(uintptr_t pc);
+ * instruction pointer. Returns NULL on failure. */
+const char *get_fn_name(uintptr_t pc);
/* Returns the address of sym, or 0 if it does not exist */
uintptr_t get_symbol_addr(char *sym);
diff --git a/kern/src/alarm.c b/kern/src/alarm.c
index 52e21d3..b147095 100644
--- a/kern/src/alarm.c
+++ b/kern/src/alarm.c
@@ -460,16 +460,13 @@
tchain->latest_time);
TAILQ_FOREACH(i, &tchain->waiters, next) {
uintptr_t f;
- char *f_name;
if (i->irq_ok)
f = (uintptr_t)i->func_irq;
else
f = (uintptr_t)i->func;
- f_name = get_fn_name(f);
printk("\tWaiter %p, time %llu, func %p (%s)\n", i,
- i->wake_up_time, f, f_name);
- kfree(f_name);
+ i->wake_up_time, f, get_fn_name(f));
}
spin_unlock_irqsave(&tchain->lock);
}
diff --git a/kern/src/atomic.c b/kern/src/atomic.c
index 5669baa..7af4cfb 100644
--- a/kern/src/atomic.c
+++ b/kern/src/atomic.c
@@ -102,17 +102,14 @@
void spinlock_debug(spinlock_t *lock)
{
uintptr_t pc = lock->call_site;
- char *func_name;
if (!pc) {
printk("Lock %p: never locked\n", lock);
return;
}
- func_name = get_fn_name(pc);
- printk("Lock %p: currently %slocked. Last locked at [<%p>] in %s on "
- "core %d\n", lock, spin_locked(lock) ? "" : "un", pc, func_name,
+ printk("Lock %p: currently %slocked. Last locked at [<%p>] in %s on core %d\n",
+ lock, spin_locked(lock) ? "" : "un", pc, get_fn_name(pc),
lock->calling_core);
- kfree(func_name);
}
#endif /* CONFIG_SPINLOCK_DEBUG */
diff --git a/kern/src/kdebug.c b/kern/src/kdebug.c
index 787de72..6937d6d 100644
--- a/kern/src/kdebug.c
+++ b/kern/src/kdebug.c
@@ -12,13 +12,13 @@
struct symtab_entry gbl_symtab[1] __attribute__((weak)) = {{0, 0}};
-/* Returns a null-terminated string with the function name for a given PC /
- * instruction pointer. kfree() the result. */
-char *get_fn_name(uintptr_t pc)
+/* Returns a null-terminated string from the reflected symbol table with the
+ * function name for a given PC / instruction pointer. Returns NULL on
+ * failure. */
+const char *get_fn_name(uintptr_t pc)
{
struct symtab_entry *i, *prev = 0, *found = 0;
- char *buf;
- size_t name_len;
+
/* Table is in ascending order. As soon as we get to an entry greater than
* us, we were in the previous one. This is only true if we were given a
* good PC. Random addresses will just find the previous symbol. */
@@ -30,14 +30,9 @@
prev = i;
}
if (!found)
- return 0;
+ return NULL;
assert(found->name);
- name_len = strlen(found->name) + 1;
- buf = kmalloc(name_len, 0);
- if (!buf)
- return 0;
- strlcpy(buf, found->name, name_len);
- return buf;
+ return found->name;
}
uintptr_t get_symbol_addr(char *sym)
@@ -204,15 +199,12 @@
void print_backtrace_list(uintptr_t *pcs, size_t nr_pcs,
void (*pfunc)(void *, const char *), void *opaque)
{
- char *func_name;
char bt_line[128];
for (size_t i = 0; i < nr_pcs; i++) {
- func_name = get_fn_name(pcs[i]);
snprintf(bt_line, sizeof(bt_line), "#%02d [<%p>] in %s\n", i + 1,
- pcs[i], func_name);
+ pcs[i], get_fn_name(pcs[i]));
pfunc(opaque, bt_line);
- kfree(func_name);
}
}
diff --git a/kern/src/monitor.c b/kern/src/monitor.c
index 3465872..6a5fcaf 100644
--- a/kern/src/monitor.c
+++ b/kern/src/monitor.c
@@ -680,16 +680,12 @@
static void emit_hwtf_backtrace(struct hw_trapframe *hw_tf)
{
- char *fn_name;
-
if (mon_verbose_trace) {
print_trapframe(hw_tf);
backtrace_hwtf(hw_tf);
}
- fn_name = get_fn_name(get_hwtf_pc(hw_tf));
printk("Core %d is at %p (%s)\n", core_id(), get_hwtf_pc(hw_tf),
- fn_name);
- kfree(fn_name);
+ get_fn_name(get_hwtf_pc(hw_tf)));
}
static void emit_vmtf_backtrace(struct vm_trapframe *vm_tf)
diff --git a/kern/src/smp.c b/kern/src/smp.c
index d11083c..43ba748 100644
--- a/kern/src/smp.c
+++ b/kern/src/smp.c
@@ -175,19 +175,18 @@
static void pcpui_trace_kmsg_handler(void *event, void *data)
{
struct pcpu_trace_event *te = (struct pcpu_trace_event*)event;
- char *func_name;
uintptr_t addr;
+
addr = te->arg1;
- func_name = get_fn_name(addr);
- printk("\tKMSG %p: %s\n", addr, func_name);
- kfree(func_name);
+ printk("\tKMSG %p: %s\n", addr, get_fn_name(addr));
}
static void pcpui_trace_locks_handler(void *event, void *data)
{
struct pcpu_trace_event *te = (struct pcpu_trace_event*)event;
- char *func_name;
+ const char *func_name;
uintptr_t lock_addr = te->arg1;
+
if (lock_addr > KERN_LOAD_ADDR)
func_name = get_fn_name(lock_addr);
else
@@ -195,8 +194,6 @@
printk("Time %uus, lock %p (%s)\n", te->arg0, lock_addr, func_name);
printk("\t");
spinlock_debug((spinlock_t*)lock_addr);
- if (lock_addr > KERN_LOAD_ADDR)
- kfree(func_name);
}
/* Add specific trace handlers here: */
diff --git a/kern/src/trap.c b/kern/src/trap.c
index c29ad8e..a854866 100644
--- a/kern/src/trap.c
+++ b/kern/src/trap.c
@@ -268,14 +268,13 @@
struct per_cpu_info *pcpui = &per_cpu_info[coreid];
void __print_kmsgs(struct kernel_msg_list *list, char *type)
{
- char *fn_name;
struct kernel_message *kmsg_i;
+
STAILQ_FOREACH(kmsg_i, list, link) {
- fn_name = get_fn_name((long)kmsg_i->pc);
printk("%s KMSG on %d from %d to run %p(%s)(%p, %p, %p)\n", type,
- kmsg_i->dstid, kmsg_i->srcid, kmsg_i->pc, fn_name,
+ kmsg_i->dstid, kmsg_i->srcid, kmsg_i->pc,
+ get_fn_name((long)kmsg_i->pc),
kmsg_i->arg0, kmsg_i->arg1, kmsg_i->arg2);
- kfree(fn_name);
}
}
__print_kmsgs(&pcpui->immed_amsgs, "Immedte");
