From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx197.postini.com [74.125.245.197]) by kanga.kvack.org (Postfix) with SMTP id 002D76B00F8 for ; Mon, 21 May 2012 16:35:44 -0400 (EDT) Received: from /spool/local by e5.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 21 May 2012 16:35:44 -0400 Received: from d01relay07.pok.ibm.com (d01relay07.pok.ibm.com [9.56.227.147]) by d01dlp01.pok.ibm.com (Postfix) with ESMTP id 169D338C805C for ; Mon, 21 May 2012 16:30:26 -0400 (EDT) Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay07.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q4LKUQwp24051940 for ; Mon, 21 May 2012 16:30:26 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q4LKUOLp025493 for ; Mon, 21 May 2012 16:30:24 -0400 Subject: [RFC][PATCH 1/2] hugetlb: fix resv_map leak in error path From: Dave Hansen Date: Mon, 21 May 2012 13:30:22 -0700 Message-Id: <20120521203022.F7FCE507@kernel> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, 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: http://marc.info/?l=linux-mm&m=133728900729735 Signed-off-by: Dave Hansen Acked-by: Mel Gorman ecked-by: KOSAKI Motohiro Reported/tested-by: Christoph Lameter --- 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 2012-05-21 13:24:38.369857759 -0700 +++ linux-2.6.git-dave/mm/hugetlb.c 2012-05-21 13:24:38.377857849 -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) diff -puN Documentation/stable_kernel_rules.txt~hugetlb-fix-leak Documentation/stable_kernel_rules.txt _ -- 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