[PATCH] PPC64: crash during firmware flash update

[PATCH] PPC64: crash during firmware flash update

[Paul Mackerras]

This patch is from Linas Vepstas <linas@austin.ibm.com>.

Race conditions during system shutdown after a firmware
flash can sometimes lead to an invalid pointer deref (deref
to freed memory).  This patch fixes this.  In addition, it makes
sure that the proc entries created by the firmware flash module
are removed when the module is unloaded. 

Signed-off-by: Linas Vepstas <linas@linas.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff -urN linux-2.5/arch/ppc64/kernel/rtas_flash.c test/arch/ppc64/kernel/rtas_flash.c
--- linux-2.5/arch/ppc64/kernel/rtas_flash.c	2004-06-25 07:03:03.000000000 +1000
+++ test/arch/ppc64/kernel/rtas_flash.c	2004-10-23 17:38:33.445013280 +1000
@@ -562,6 +562,7 @@
 		validate_flash(args_buf);
 	}
 
+	/* The matching atomic_inc was in rtas_excl_open() */
 	atomic_dec(&dp->count);
 
 	return 0;
@@ -572,7 +573,8 @@
 	if (dp) {
 		if (dp->data != NULL)
 			kfree(dp->data);
-		remove_proc_entry(dp->name, NULL);
+		dp->owner = NULL;
+		remove_proc_entry(dp->name, dp->parent);
 	}
 }