From b1becbdee776b447f203aa8da9a40488d5a75e1d Mon Sep 17 00:00:00 2001 From: Bob Peterson Date: Thu, 17 Jun 2010 16:45:37 -0400 Subject: [PATCH] GFS2: Fix kernel NULL pointer dereference by dlm_astd This patch fixes a problem in an error path when looking up dinodes. There are two sister-functions, gfs2_inode_lookup and gfs2_process_unlinked_inode. Both functions acquire and hold the i_iopen glock for the dinode being looked up. The last thing they try to do is hold the i_gl glock for the dinode. If that glock fails for some reason, the error path was incorrectly calling gfs2_glock_put for the i_iopen glock twice. This resulted in the glock being prematurely freed. The "minimum hold time" usually kept the glock in memory, but the lock interface to dlm (aka lock_dlm) freed its memory for the glock. In some circumstances, it would cause dlm's dlm_astd daemon to try to call the bast function for the freed lock_dlm memory, which resulted in a NULL pointer dereference. Signed-off-by: Bob Peterson Signed-off-by: Steven Whitehouse --- Reading git-format-patch failed