From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932509AbaKRWRQ (ORCPT ); Tue, 18 Nov 2014 17:17:16 -0500 Received: from mga14.intel.com ([192.55.52.115]:19797 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932430AbaKRWRP (ORCPT ); Tue, 18 Nov 2014 17:17:15 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,412,1413270000"; d="scan'208";a="624500410" Subject: [PATCH] shmdt: use i_size_read() instead of ->i_size To: linux-kernel@vger.kernel.org Cc: Dave Hansen , dave.hansen@linux.intel.com, akpm@linux-foundation.org, manfred@colorfullife.com, davidlohr@hp.com From: Dave Hansen Date: Tue, 18 Nov 2014 14:17:12 -0800 Message-Id: <20141118221712.E0062E98@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen Andrew Morton noted http://lkml.kernel.org/r/20141104142027.a7a0d010772d84560b445f59@linux-foundation.org that the shmdt uses inode->i_size outside of i_mutex being held. There is one more case in shm.c in shm_destroy(). This converts both users over to use i_size_read(). Signed-off-by: Dave Hansen Cc: Andrew Morton Cc: Manfred Spraul Cc: Davidlohr Bueso --- b/ipc/shm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff -puN ipc/shm.c~shmdt-use-i_isize_read ipc/shm.c --- a/ipc/shm.c~shmdt-use-i_isize_read 2014-11-18 11:13:52.293599642 -0800 +++ b/ipc/shm.c 2014-11-18 11:16:47.354495228 -0800 @@ -219,7 +219,8 @@ static void shm_destroy(struct ipc_names if (!is_file_hugepages(shm_file)) shmem_lock(shm_file, 0, shp->mlock_user); else if (shp->mlock_user) - user_shm_unlock(file_inode(shm_file)->i_size, shp->mlock_user); + user_shm_unlock(i_size_read(file_inode(shm_file)), + shp->mlock_user); fput(shm_file); ipc_rcu_putref(shp, shm_rcu_free); } @@ -1272,7 +1273,7 @@ SYSCALL_DEFINE1(shmdt, char __user *, sh (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) { - size = file_inode(vma->vm_file)->i_size; + size = i_size_read(file_inode(vma->vm_file)); do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); /* * We discovered the size of the shm segment, so _