Re: arch/arm64/kernel/signal.c:663:43: sparse: sparse: incorrect type in argument 1 (different address spaces)

From: Catalin Marinas
Date: Tue May 31 2022 - 13:07:15 EST

On Sat, May 28, 2022 at 07:40:31AM +0800, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: bf272460d744112bacd4c4d562592decbf0edf64
> commit: a1f4ccd25cc256255813f584f10e5527369d4a02 arm64/sme: Provide Kconfig for SME
> date: 5 weeks ago
> config: arm64-randconfig-s032-20220527 (https://download.01.org/0day-ci/archive/20220528/202205280710.c7k1K4sD-lkp@xxxxxxxxx/config)
> compiler: aarch64-linux-gcc (GCC) 11.3.0
> reproduce:
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # apt-get install sparse
> # sparse version: v0.6.4-14-g5a0004b5-dirty
> # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a1f4ccd25cc256255813f584f10e5527369d4a02
> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> git fetch --no-tags linus master
> git checkout a1f4ccd25cc256255813f584f10e5527369d4a02
> # save the config file
> mkdir build_dir && cp config build_dir/.config
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=arm64 SHELL=/bin/bash arch/arm64/kernel/
>
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>
>
> sparse warnings: (new ones prefixed by >>)
> >> arch/arm64/kernel/signal.c:663:43: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected struct user_ctxs [noderef] __user *user @@ got struct user_ctxs * @@
> arch/arm64/kernel/signal.c:663:43: sparse: expected struct user_ctxs [noderef] __user *user
> arch/arm64/kernel/signal.c:663:43: sparse: got struct user_ctxs *
> arch/arm64/kernel/signal.c:933:26: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected void ( [noderef] [usertype] __user *[assigned] [usertype] sigtramp )( ... ) @@ got void * @@
> arch/arm64/kernel/signal.c:933:26: sparse: expected void ( [noderef] [usertype] __user *[assigned] [usertype] sigtramp )( ... )
> arch/arm64/kernel/signal.c:933:26: sparse: got void *
> >> arch/arm64/kernel/signal.c:394:35: sparse: sparse: dereference of noderef expression
> >> arch/arm64/kernel/signal.c:394:35: sparse: sparse: dereference of noderef expression
> arch/arm64/kernel/signal.c:428:53: sparse: sparse: dereference of noderef expression
> arch/arm64/kernel/signal.c:428:53: sparse: sparse: dereference of noderef expression
>
> vim +663 arch/arm64/kernel/signal.c
>
> 47ccb02868cead Dave Martin 2017-06-15 620
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 621 static int restore_sigframe(struct pt_regs *regs,
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 622 struct rt_sigframe __user *sf)
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 623 {
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 624 sigset_t set;
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 625 int i, err;
> 47ccb02868cead Dave Martin 2017-06-15 626 struct user_ctxs user;
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 627
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 628 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 629 if (err == 0)
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 630 set_current_blocked(&set);
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 631
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 632 for (i = 0; i < 31; i++)
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 633 __get_user_error(regs->regs[i], &sf->uc.uc_mcontext.regs[i],
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 634 err);
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 635 __get_user_error(regs->sp, &sf->uc.uc_mcontext.sp, err);
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 636 __get_user_error(regs->pc, &sf->uc.uc_mcontext.pc, err);
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 637 __get_user_error(regs->pstate, &sf->uc.uc_mcontext.pstate, err);
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 638
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 639 /*
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 640 * Avoid sys_rt_sigreturn() restarting.
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 641 */
> 17c28958600928 Dave Martin 2017-08-01 642 forget_syscall(regs);
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 643
> dbd4d7ca563fd0 Mark Rutland 2016-03-01 644 err |= !valid_user_regs(&regs->user_regs, current);
> 47ccb02868cead Dave Martin 2017-06-15 645 if (err == 0)
> 47ccb02868cead Dave Martin 2017-06-15 646 err = parse_user_sigframe(&user, sf);
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 647
> 6d502b6ba1b267 Suzuki K Poulose 2020-01-13 648 if (err == 0 && system_supports_fpsimd()) {
> 8cd969d28fd284 Dave Martin 2017-10-31 649 if (!user.fpsimd)
> 8cd969d28fd284 Dave Martin 2017-10-31 650 return -EINVAL;
> 8cd969d28fd284 Dave Martin 2017-10-31 651
> 8cd969d28fd284 Dave Martin 2017-10-31 652 if (user.sve) {
> 8cd969d28fd284 Dave Martin 2017-10-31 653 if (!system_supports_sve())
> 8cd969d28fd284 Dave Martin 2017-10-31 654 return -EINVAL;
> 8cd969d28fd284 Dave Martin 2017-10-31 655
> 8cd969d28fd284 Dave Martin 2017-10-31 656 err = restore_sve_fpsimd_context(&user);
> 8cd969d28fd284 Dave Martin 2017-10-31 657 } else {
> 47ccb02868cead Dave Martin 2017-06-15 658 err = restore_fpsimd_context(user.fpsimd);
> 8cd969d28fd284 Dave Martin 2017-10-31 659 }
> 8cd969d28fd284 Dave Martin 2017-10-31 660 }
> 2c020ed8d148f7 Catalin Marinas 2012-03-05 661
> 39782210eb7e87 Mark Brown 2022-04-19 662 if (err == 0 && system_supports_sme() && user.za)
> 39782210eb7e87 Mark Brown 2022-04-19 @663 err = restore_za_context(&user);

I think the restore_za_context() definition is wrong. struct user_ctxs
__user *user shouldn't have the '__user' annotation, that's for the
pointers inside the structure. So:

diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index edb2d9206a78..b0980fbb6bc7 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -385,7 +385,7 @@ static int preserve_za_context(struct za_context __user *ctx)
return err ? -EFAULT : 0;
}

-static int restore_za_context(struct user_ctxs __user *user)
+static int restore_za_context(struct user_ctxs *user)
{
int err;
unsigned int vq;

I'll do some proper patches tomorrow and send them for -rc1.

--
Catalin