Hi Rafael, On 2018/5/9 5:20, Rafael J. Wysocki wrote: > On Mon, May 7, 2018 at 10:06 AM, Yisheng Xie <xieyisheng1@xxxxxxxxxx> wrote: >> >> >> On 2018/5/1 17:28, Rafael J. Wysocki wrote: >>>> drivers/acpi/pci_root.c | 2 +- >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c >>>>> index 6fc204a..b758ca3 100644 >>>>> --- a/drivers/acpi/pci_root.c >>>>> +++ b/drivers/acpi/pci_root.c >>>>> @@ -746,7 +746,7 @@ static void acpi_pci_root_remap_iospace(struct resource_entry *entry) >>>>> goto err; >>>>> >>>>> res->start = port; >>>>> - res->end = port + length - 1; >>>>> + res->end = PAGE_ALIGN(port + length) - 1; >>> Shouldn't pci_remap_iospace() sanitize its arguments instead? >> >> Yeah, I thought that pci_remap_iospace() will be called at many place, and presently I >> had not seen any problem at other place except acpi_pci_root_remap_iospace(). Anyway, >> sanitize arguments in pci_remap_iospace() can resolve the problem more thoroughly, but >> should more common, right? >> >> Therefore, is the follow change ok from your point of view? >> >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >> index e597655..8607298 100644 >> --- a/drivers/pci/pci.c >> +++ b/drivers/pci/pci.c >> @@ -3527,6 +3527,9 @@ int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr) >> if (res->end > IO_SPACE_LIMIT) >> return -EINVAL; >> >> + if (!PAGE_ALIGNED(vaddr) || !PAGE_ALIGNED(resource_size(res))) >> + return -EINVAL; >> + >> return ioremap_page_range(vaddr, vaddr + resource_size(res), phys_addr, >> pgprot_device(PAGE_KERNEL)); >> #else > > I'd rather apply PAGE_ALIGN() to the arguments of ioremap_page_range() > and call it anyway. It will fail if the mapping cannot be created. > Hmm, here is a corner case which take 64k page size as an example: step 1. someone call pci_remap_iospace() with res: res->start 0x1000, resource_size(res) 0x1000 after PAGE_ALIGN(), the arguments of ioremap_page_range() will be addr: (PCI_IOBASE + PAGE_SIZE), end: (PCI_IOBASE + 2*PAGE_SIZE) and ioremap_page_range will be ok. step 2. another one call pci_remap_iospace() with res: res->start 0x2000, resource_size(res) 0x1000 after PAGE_ALIGN(), the arguments of ioremap_page_range() also will be: addr: (PCI_IOBASE + PAGE_SIZE), end: (PCI_IOBASE + 2*PAGE_SIZE) then ioremap_page_range() will also trigger BUG_ON(!pte_none(*pte)); for the pte is not none after step 1, right? ps, if let addr = vaddr && PAGE_MASK, above case seems also will trigger BUG_ON. Actually, I am not sure whether the above case is exist in real system. Thanks Yisheng > . >
