From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1g2bz1-00005R-8h for kexec@lists.infradead.org; Wed, 19 Sep 2018 12:54:34 +0000 From: Lianbo Jiang Subject: [PATCH 1/3 v2] resource: fix an error which walks through iomem resources Date: Wed, 19 Sep 2018 20:52:49 +0800 Message-Id: <20180919125251.8181-2-lijiang@redhat.com> In-Reply-To: <20180919125251.8181-1-lijiang@redhat.com> References: <20180919125251.8181-1-lijiang@redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: linux-kernel@vger.kernel.org Cc: thomas.lendacky@amd.com, brijesh.singh@amd.com, tiwai@suse.de, x86@kernel.org, kexec@lists.infradead.org, mingo@redhat.com, baiyaowei@cmss.chinamobile.com, hpa@zytor.com, bhelgaas@google.com, tglx@linutronix.de, bp@suse.de, dyoung@redhat.com, akpm@linux-foundation.org, dan.j.williams@intel.com When we walk through iomem resources by calling walk_iomem_res_desc(), the values of the function parameter may be modified in the while loop of __walk_iomem_res_desc(), which will cause us to not get the desired result in some cases. At present, it only restores the original value of res->end, but it doesn't restore the original value of res->flags in the while loop of __walk_iomem _res_desc(). Whenever the find_next_iomem_res() finds a resource and returns the result, the original values of this resource will be modified, which might lead to an error in the next loop. For example: The original value of resource flags is: res->flags=0x80000200(initial value) p->flags _ 0x81000200 _ _ 0x80000200 _ / \ / \ |________|_______A________|____|_....._|______B_________|..........___| 0 0xffffffff (memory address ranges) Note: if ((p->flags & res->flags) != res->flags) continue; When the resource A is found, the original value of this resource flags will be changed to 0x81000200(res->flags=0x81000200), and continue to look for the next resource, when the loop reaches resource B, it can not get the resource B any more(you can refer to the for loop of find_next _iomem_res()), because the value of conditional expression will become true and will also jump the resource B. In fact, we should get the resource A and B when we walk through the whole tree, but it only gets the resource A, the resource B is missed. Signed-off-by: Dave Young Signed-off-by: Lianbo Jiang --- kernel/resource.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/resource.c b/kernel/resource.c index 30e1bc68503b..f5d9fc70a04c 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -375,6 +375,7 @@ static int __walk_iomem_res_desc(struct resource *res, unsigned long desc, int (*func)(struct resource *, void *)) { u64 orig_end = res->end; + u64 orig_flags = res->flags; int ret = -1; while ((res->start < res->end) && @@ -385,6 +386,7 @@ static int __walk_iomem_res_desc(struct resource *res, unsigned long desc, res->start = res->end + 1; res->end = orig_end; + res->flags = orig_flags; } return ret; -- 2.17.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec