On Thu, Sep 09, 2021 at 08:45:56AM -0700, Kees Cook wrote: > On Thu, Sep 09, 2021 at 11:49:55AM +0800, kernel test robot wrote: > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > > head: 999569d59a0aa2509ae4a67ecc266c1134e37e7b > > commit: f5b1a5d922d3199e0637349239b43aed6c7656b9 [12105/12116] mm/vmalloc: add __alloc_size attributes for better bounds checking > > config: i386-randconfig-a002-20200329 (attached as .config) > > compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 > > reproduce (this is a W=1 build): > > # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=f5b1a5d922d3199e0637349239b43aed6c7656b9 > > git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git > > git fetch --no-tags linux-next master > > git checkout f5b1a5d922d3199e0637349239b43aed6c7656b9 > > # save the attached .config to linux build tree > > mkdir build_dir > > make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/rapidio/devices/ > > > > If you fix the issue, kindly add following tag as appropriate > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > > > All errors (new ones prefixed by >>): > > > > In file included from arch/x86/include/asm/preempt.h:7, > > from include/linux/preempt.h:78, > > from include/linux/spinlock.h:55, > > from include/linux/mm_types.h:9, > > from include/linux/buildid.h:5, > > from include/linux/module.h:14, > > from drivers/rapidio/devices/rio_mport_cdev.c:13: > > In function 'check_copy_size', > > inlined from 'copy_from_user' at include/linux/uaccess.h:191:6, > > inlined from 'rio_mport_transfer_ioctl' at drivers/rapidio/devices/rio_mport_cdev.c:983:6: > > >> include/linux/thread_info.h:213:4: error: call to '__bad_copy_to' declared with attribute error: copy destination size is too small > > 213 | __bad_copy_to(); > > | ^~~~~~~~~~~~~~~ > > > transfer = vmalloc(array_size(sizeof(*transfer), transaction.count)); > if (!transfer) > return -ENOMEM; > > if (unlikely(copy_from_user(transfer, > (void __user *)(uintptr_t)transaction.block, > array_size(sizeof(*transfer), transaction.count)))) { > > Uhhhmm... allocation size and copy size are identical... > > array_size(sizeof(*transfer), transaction.count) > array_size(sizeof(*transfer), transaction.count) This appears to be an optimization(?) bug in GCC 9.3. This warning (correctly) does not appear in later versions. -- Kees Cook
