lockdebug improvement to pass/log return address in more places

[Rafal Boni <rafal%pobox.com@localhost>]

Folks:
        I'm trying to track down an early UVM panic where I can't get into
        DDB (why is an orthogonal issue... I'm not sure yet as to why), and
        unfortunately LOCKDEBUG isn't giving me enough useful info when it
        panics (in this case attempting to lock a non-existent lock).

        What does everyone think of the following patch to help improve
        the situation at least a little?

Thanks!
--rafal

Index: subr_lockdebug.c
===================================================================
RCS file: /cvsroot/src/sys/kern/subr_lockdebug.c,v
retrieving revision 1.32
diff -u -p -r1.32 subr_lockdebug.c
--- subr_lockdebug.c    3 May 2008 06:24:55 -0000       1.32
+++ subr_lockdebug.c    6 May 2008 17:35:58 -0000
@@ -242,13 +242,13 @@ lockdebug_lookup1(volatile void *lock, l
  *     Find a lockdebug structure by a pointer to a lock and return it locked.
  */
 static inline lockdebug_t *
-lockdebug_lookup(volatile void *lock, lockdebuglk_t **lk)
+lockdebug_lookup(volatile void *lock, lockdebuglk_t **lk, uintptr_t where)
 {
        lockdebug_t *ld;
 
        ld = lockdebug_lookup1(lock, lk);
        if (ld == NULL)
-               panic("lockdebug_lookup: uninitialized lock (lock=%p)", lock);
+               panic("lockdebug_lookup: uninitialized lock (lock=%p, 
from=%08lx)", lock, where);
        return ld;
 }
 
@@ -382,7 +382,8 @@ lockdebug_free(volatile void *lock)
        if (panicstr != NULL || ld_panic)
                return;
 
-       ld = lockdebug_lookup(lock, &lk);
+       ld = lockdebug_lookup(lock, &lk, 
+           (uintptr_t) __builtin_return_address(0));
        if (ld == NULL) {
                panic("lockdebug_free: destroying uninitialized lock %p"
                    "(ld_lock=%p)", lock, ld->ld_lock);
@@ -473,7 +474,7 @@ lockdebug_wantlock(volatile void *lock, 
        if (panicstr != NULL || ld_panic)
                return;
 
-       if ((ld = lockdebug_lookup(lock, &lk)) == NULL)
+       if ((ld = lockdebug_lookup(lock, &lk, where)) == NULL)
                return;
 
        if ((ld->ld_flags & LD_LOCKED) != 0 || ld->ld_shares != 0) {
@@ -522,7 +523,7 @@ lockdebug_locked(volatile void *lock, ui
        if (panicstr != NULL || ld_panic)
                return;
 
-       if ((ld = lockdebug_lookup(lock, &lk)) == NULL)
+       if ((ld = lockdebug_lookup(lock, &lk, where)) == NULL)
                return;
 
        if (shared) {
@@ -569,7 +570,7 @@ lockdebug_unlocked(volatile void *lock, 
        if (panicstr != NULL || ld_panic)
                return;
 
-       if ((ld = lockdebug_lookup(lock, &lk)) == NULL)
+       if ((ld = lockdebug_lookup(lock, &lk, where)) == NULL)
                return;
 
        if (shared) {
@@ -839,7 +840,8 @@ lockdebug_abort(volatile void *lock, loc
        lockdebug_t *ld;
        lockdebuglk_t *lk;
 
-       if ((ld = lockdebug_lookup(lock, &lk)) != NULL) {
+       if ((ld = lockdebug_lookup(lock, &lk, 
+           (uintptr_t) __builtin_return_address(0))) != NULL) {
                lockdebug_abort1(ld, lk, func, msg, true);
                /* NOTREACHED */
        }

-- 
  Time is an illusion; lunchtime, doubly so.     |/\/\|           Rafal Boni
                   -- Ford Prefect               |\/\/|      
rafal%pobox.com@localhost