Messages in this thread | | | Date | Tue, 28 Dec 2021 12:51:03 +0800 | Subject | Re: [PATCH v2 2/2] mm: usercopy: Warn vmalloc/module address in check_heap_object() | From | Kefeng Wang <> |
| |
On 2021/12/27 1:33, Christophe Leroy wrote: > > Le 25/12/2021 à 13:06, Kefeng Wang a écrit : >> virt_addr_valid() could be insufficient to validate the virt addr >> on some architecture, which could lead to potential BUG which has >> been found on arm64/powerpc64. >> >> Let's add WARN_ON to check if the virt addr is passed virt_addr_valid() >> but is a vmalloc/module address. > I think that's the responsibility of the architecture and doesn't > deserve a WARN_ON() in generic code. > > The generic code cannot check all what architectures do wrong. > > Eventually you can do some testing at startup, maybe with > CONFIG_DEBUG_VM_PGTABLE, but I don't think we should have such > verification in functions like check_heap_object()
Ok, we could find other better place to add a virt_to_valid() check
instead of this one.
>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> >> --- >> mm/usercopy.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/mm/usercopy.c b/mm/usercopy.c >> index b3de3c4eefba..ce83e0b137dd 100644 >> --- a/mm/usercopy.c >> +++ b/mm/usercopy.c >> @@ -228,6 +228,8 @@ static inline void check_heap_object(const void *ptr, unsigned long n, >> if (!virt_addr_valid(ptr)) >> return; >> >> + WARN_ON_ONCE(is_vmalloc_or_module_addr(ptr)); >> + >> /* >> * When CONFIG_HIGHMEM=y, kmap_to_page() will give either the >> * highmem page or fallback to virt_to_page(). The following
| |