From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx150.postini.com [74.125.245.150]) by kanga.kvack.org (Postfix) with SMTP id 18C306B0062 for ; Tue, 5 Jun 2012 18:42:23 -0400 (EDT) From: Jan Kara Subject: [PATCH] mm: Make vb_alloc() more foolproof Date: Wed, 6 Jun 2012 00:40:56 +0200 Message-Id: <1338936056-4092-1-git-send-email-jack@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, Jan Kara If someone calls vb_alloc() (or vm_map_ram() for that matter) to allocate 0 bytes (0 pages), get_order() returns BITS_PER_LONG - PAGE_CACHE_SHIFT and interesting stuff happens. So make debugging such problems easier and warn about 0-size allocation. Signed-off-by: Jan Kara --- mm/vmalloc.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 2aad499..bebee70 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -904,6 +904,15 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask) BUG_ON(size & ~PAGE_MASK); BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC); + if (size == 0) { + /* + * Allocating 0 bytes isn't what caller wants since + * get_order(0) returns funny result. Just warn and terminate + * early. + */ + WARN_ON(1); + return NULL; + } order = get_order(size); again: -- 1.7.1 -- 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