From: Dave Hansen dave.hansen@linux.intel.com

mainline inclusion from mainline-v5.1-rc1 commit 5cd401ace914dc68556c6d2fcae0c349444d5f86 category: bugfix bugzilla: 17339 CVE: NA

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walk_system_ram_range() can return an error code either becuase *it* failed, or because the 'func' that it calls returned an error. The memory hotplug does the following:

ret = walk_system_ram_range(..., func); if (ret) return ret;

and 'ret' makes it out to userspace, eventually. The problem s, walk_system_ram_range() failues that result from *it* failing (as opposed to 'func') return -1. That leads to a very odd -EPERM (-1) return code out to userspace.

Make walk_system_ram_range() return -EINVAL for internal failures to keep userspace less confused.

This return code is compatible with all the callers that I audited.

Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Reviewed-by: Bjorn Helgaas bhelgaas@google.com Acked-by: Michael Ellerman mpe@ellerman.id.au (powerpc) Cc: Dan Williams dan.j.williams@intel.com Cc: Dave Jiang dave.jiang@intel.com Cc: Ross Zwisler zwisler@kernel.org Cc: Vishal Verma vishal.l.verma@intel.com Cc: Tom Lendacky thomas.lendacky@amd.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Michal Hocko mhocko@suse.com Cc: linux-nvdimm@lists.01.org Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org Cc: Huang Ying ying.huang@intel.com Cc: Fengguang Wu fengguang.wu@intel.com Cc: Borislav Petkov bp@suse.de Cc: Yaowei Bai baiyaowei@cmss.chinamobile.com Cc: Takashi Iwai tiwai@suse.de Cc: Jerome Glisse jglisse@redhat.com Cc: Benjamin Herrenschmidt benh@kernel.crashing.org Cc: Paul Mackerras paulus@samba.org Cc: linuxppc-dev@lists.ozlabs.org Cc: Keith Busch keith.busch@intel.com Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Hanjun Guo guohanjun@huawei.com --- kernel/resource.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/resource.c b/kernel/resource.c index bce773c..7dd11c7 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -377,7 +377,7 @@ static int __walk_iomem_res_desc(resource_size_t start, resource_size_t end, int (*func)(struct resource *, void *)) { struct resource res; - int ret = -1; + int ret = -EINVAL;

while (start < end && !find_next_iomem_res(start, end, flags, desc, @@ -456,7 +456,7 @@ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages, unsigned long flags; struct resource res; unsigned long pfn, end_pfn; - int ret = -1; + int ret = -EINVAL;

start = (u64) start_pfn << PAGE_SHIFT; end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;