* Don Lewis <[EMAIL PROTECTED]> [030617 12:00] wrote:
> It's not legal to attempt to aquire Giant in fdrop_locked(), while
> FILE_LOCK() is held. The problem is that FILE_LOCK uses the mutex pool,
> which should only be used for leaf mutexes.
>
> It also looks like there is a potential for a lock order reversal if
> some callers aquire Giant before FILE_LOCK() and fdrop_locked() does the
> opposite.
>
> It also appears that witness ignores the mutex pool ...
Yes, but I think the fix is as simple as just dropping the FILE_LOCK
after the decrement as we're the last holders of it, can you try
this:
Index: kern_descrip.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_descrip.c,v
retrieving revision 1.199
diff -u -r1.199 kern_descrip.c
--- kern_descrip.c 11 Jun 2003 00:56:55 -0000 1.199
+++ kern_descrip.c 17 Jun 2003 19:07:01 -0000
@@ -2003,6 +2003,7 @@
FILE_UNLOCK(fp);
return (0);
}
+ FILE_UNLOCK(fp);
mtx_lock(&Giant);
if (fp->f_count < 0)
panic("fdrop: count < 0");
@@ -2012,10 +2013,8 @@
lf.l_len = 0;
lf.l_type = F_UNLCK;
vp = fp->f_data;
- FILE_UNLOCK(fp);
(void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
- } else
- FILE_UNLOCK(fp);
+ }
if (fp->f_ops != &badfileops)
error = fo_close(fp, td);
else
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