arch/x86/kernel/shstk.c:295:55: sparse: sparse: cast removes address space '__user' of expression

From: kernel test robot
Date: Sun Jan 07 2024 - 11:31:42 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 52b1853b080a082ec3749c3a9577f6c71b1d4a90
commit: 05e36022c0543ba55a3de55af455b00cb3eb4fcc x86/shstk: Handle signals for shadow stack
date: 5 months ago
config: x86_64-randconfig-123-20240106 (https://download.01.org/0day-ci/archive/20240108/202401080003.duO4RmjK-lkp@xxxxxxxxx/config)
compiler: ClangBuiltLinux clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240108/202401080003.duO4RmjK-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401080003.duO4RmjK-lkp@xxxxxxxxx/

sparse warnings: (new ones prefixed by >>)
arch/x86/kernel/shstk.c:244:29: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected unsigned long long [noderef] [usertype] __user *addr @@ got void *[noderef] __user @@
arch/x86/kernel/shstk.c:244:29: sparse: expected unsigned long long [noderef] [usertype] __user *addr
arch/x86/kernel/shstk.c:244:29: sparse: got void *[noderef] __user
>> arch/x86/kernel/shstk.c:295:55: sparse: sparse: cast removes address space '__user' of expression

vim +/__user +295 arch/x86/kernel/shstk.c

271
272 int setup_signal_shadow_stack(struct ksignal *ksig)
273 {
274 void __user *restorer = ksig->ka.sa.sa_restorer;
275 unsigned long ssp;
276 int err;
277
278 if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK) ||
279 !features_enabled(ARCH_SHSTK_SHSTK))
280 return 0;
281
282 if (!restorer)
283 return -EINVAL;
284
285 ssp = get_user_shstk_addr();
286 if (unlikely(!ssp))
287 return -EINVAL;
288
289 err = shstk_push_sigframe(&ssp);
290 if (unlikely(err))
291 return err;
292
293 /* Push restorer address */
294 ssp -= SS_FRAME_SIZE;
> 295 err = write_user_shstk_64((u64 __user *)ssp, (u64)restorer);
296 if (unlikely(err))
297 return -EFAULT;
298
299 fpregs_lock_and_load();
300 wrmsrl(MSR_IA32_PL3_SSP, ssp);
301 fpregs_unlock();
302
303 return 0;
304 }
305

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