Re: [PATCH] protect remove_proc_entry

On Fri, 2005-12-30 at 13:55 -0800, Mitchell Blank Jr wrote:
> Steven Rostedt wrote:
> > I've added a global remove_proc_lock to protect this section of code. I
> > was going to add a lock to proc_dir_entry so that the locking is only
> > cut down to the same parent, but since this function is called so
> > infrequently, why waste more memory then is needed. One global lock
> > should not cause too much of a headache here.
>
> Are you sure that it's the only place where we need guard ->subdir? It
> looks like proc_lookup() and proc_readdir() use the BLK when walking that
> list, so probably the best fix would be to use that lock everywhere else
> ->subdir is touched

Good point.

God, we should be getting rid of the stupid BKL, not add more. But
seeing that this is what is used to protect that list, I guess I'll add
it.

I'm also assuming that interrupt context wont use this.

-- Steve

Index: linux-2.6.15-rc7/fs/proc/generic.c
===================================================================
--- linux-2.6.15-rc7.orig/fs/proc/generic.c 2005-12-30 14:19:39.000000000 -0500
+++ linux-2.6.15-rc7/fs/proc/generic.c 2005-12-30 17:05:56.000000000 -0500
@@ -693,6 +693,8 @@
if (!parent && xlate_proc_name(name, &parent, &fn) != 0)
goto out;
len = strlen(fn);
+
+ lock_kernel();
for (p = &parent->subdir; *p; p=&(*p)->next ) {
if (!proc_match(len, fn, *p))
continue;
@@ -713,6 +715,7 @@
}
break;
}
+ unlock_kernel();
out:
return;
}


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