From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx207.postini.com [74.125.245.207]) by kanga.kvack.org (Postfix) with SMTP id AD4F76B0082 for ; Fri, 18 May 2012 14:48:08 -0400 (EDT) Received: from /spool/local by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 18 May 2012 12:48:00 -0600 Received: from d03relay03.boulder.ibm.com (d03relay03.boulder.ibm.com [9.17.195.228]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id 552C71FF0029 for ; Fri, 18 May 2012 12:46:57 -0600 (MDT) Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by d03relay03.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q4IIkgkn159786 for ; Fri, 18 May 2012 12:46:45 -0600 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q4IIkbfg004523 for ; Fri, 18 May 2012 12:46:41 -0600 Subject: [RFC][PATCH] hugetlb: fix resv_map leak in error path From: Dave Hansen Date: Fri, 18 May 2012 11:46:30 -0700 Message-Id: <20120518184630.FF3307BD@kernel> Sender: owner-linux-mm@kvack.org List-ID: To: cl@linux.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, aarcange@redhat.com, kosaki.motohiro@jp.fujitsu.com, hughd@google.com, rientjes@google.com, adobriyan@gmail.com, akpm@linux-foundation.org, mel@csn.ul.ie, Dave Hansen When called for anonymous (non-shared) mappings, hugetlb_reserve_pages() does a resv_map_alloc(). It depends on code in hugetlbfs's vm_ops->close() to release that allocation. However, in the mmap() failure path, we do a plain unmap_region() without the remove_vma() which actually calls vm_ops->close(). This is a decent fix. This leak could get reintroduced if new code (say, after hugetlb_reserve_pages() in hugetlbfs_file_mmap()) decides to return an error. But, I think it would have to unroll the reservation anyway. This hasn't been extensively tested. Pretty much compile and boot tested along with Christoph's test case. Comments? Signed-off-by: Dave Hansen --- linux-2.6.git-dave/mm/hugetlb.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) diff -puN mm/hugetlb.c~hugetlb-fix-leak mm/hugetlb.c --- linux-2.6.git/mm/hugetlb.c~hugetlb-fix-leak 2012-05-18 11:45:50.355089708 -0700 +++ linux-2.6.git-dave/mm/hugetlb.c 2012-05-18 11:45:50.363089800 -0700 @@ -2157,6 +2157,15 @@ static void hugetlb_vm_op_open(struct vm kref_get(&reservations->refs); } +static void resv_map_put(struct vm_area_struct *vma) +{ + struct resv_map *reservations = vma_resv_map(vma); + + if (!reservations) + return; + kref_put(&reservations->refs, resv_map_release); +} + static void hugetlb_vm_op_close(struct vm_area_struct *vma) { struct hstate *h = hstate_vma(vma); @@ -2173,7 +2182,7 @@ static void hugetlb_vm_op_close(struct v reserve = (end - start) - region_count(&reservations->regions, start, end); - kref_put(&reservations->refs, resv_map_release); + resv_map_put(vma); if (reserve) { hugetlb_acct_memory(h, -reserve); @@ -2990,12 +2999,16 @@ int hugetlb_reserve_pages(struct inode * set_vma_resv_flags(vma, HPAGE_RESV_OWNER); } - if (chg < 0) - return chg; + if (chg < 0) { + ret = chg; + goto out_err; + } /* There must be enough pages in the subpool for the mapping */ - if (hugepage_subpool_get_pages(spool, chg)) - return -ENOSPC; + if (hugepage_subpool_get_pages(spool, chg)) { + ret = -ENOSPC; + goto out_err; + } /* * Check enough hugepages are available for the reservation. @@ -3004,7 +3017,7 @@ int hugetlb_reserve_pages(struct inode * ret = hugetlb_acct_memory(h, chg); if (ret < 0) { hugepage_subpool_put_pages(spool, chg); - return ret; + goto out_err; } /* @@ -3021,6 +3034,9 @@ int hugetlb_reserve_pages(struct inode * if (!vma || vma->vm_flags & VM_MAYSHARE) region_add(&inode->i_mapping->private_list, from, to); return 0; +out_err: + resv_map_put(vma); + return ret; } void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org