Subject: Re: [PATCH v2 4/5] uaccess: Disable -Wshadow in __scoped_user_access()

From: kernel test robot <[email-masked]>
Date: Thu, 5 Mar 2026 16:10:36 +0800

Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on brauner-vfs/vfs.all]
[also build test ERROR on v7.0-rc2]
[cannot apply to linus/master next-20260303]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/david-laight-linux-gmail-com/uaccess-Fix-scoped_user_read_access-for-pointer-to-const/20260302-213317
base:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git vfs.all
patch link:    https://lore.kernel.org/r/20260302132755.1475451-5-david.laight.linux%40gmail.com
patch subject: [PATCH v2 4/5] uaccess: Disable -Wshadow in __scoped_user_access()
config: nios2-allnoconfig (https://download.01.org/0day-ci/archive/20260305/[email-masked]/config)
compiler: nios2-linux-gcc (GCC) 11.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260305/[email-masked]/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 <[email-masked]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email-masked]/

All error/warnings (new ones prefixed by >>):

   In file included from include/asm-generic/div64.h:27,
                    from ./arch/nios2/include/generated/asm/div64.h:1,
                    from include/linux/math.h:6,
                    from include/linux/math64.h:6,
                    from include/linux/time.h:6,
                    from include/linux/compat.h:10,
                    from kernel/futex/core.c:34:
   kernel/futex/futex.h: In function 'futex_get_value_locked':
>> include/linux/uaccess.h:740:20: warning: unused variable '_tmpptr' [-Wunused-variable]
     740 |         with (auto _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl))        \
         |                    ^~~~~~~
   include/linux/compiler.h:396:14: note: in definition of macro 'and_with'
     396 |         for (declaration; !_with_done; _with_done = true)
         |              ^~~~~~~~~~~
   include/linux/uaccess.h:740:9: note: in expansion of macro 'with'
     740 |         with (auto _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl))        \
         |         ^~~~
   include/linux/uaccess.h:755:9: note: in expansion of macro '__scoped_user_access'
     755 |         __scoped_user_access(read, usrc, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:767:9: note: in expansion of macro 'scoped_user_read_access_size'
     767 |         scoped_user_read_access_size(usrc, sizeof(*(usrc)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:831:9: note: in expansion of macro 'scoped_user_read_access'
     831 |         scoped_user_read_access(_tmpsrc, efault)                \
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/futex.h:288:16: note: in expansion of macro 'get_user_inline'
     288 |         return get_user_inline(*dest, from);
         |                ^~~~~~~~~~~~~~~
>> include/linux/compiler.h:396:9: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
     396 |         for (declaration; !_with_done; _with_done = true)
         |         ^~~
   include/linux/compiler.h:394:17: note: in expansion of macro 'and_with'
     394 |                 and_with (declaration)
         |                 ^~~~~~~~
   include/linux/uaccess.h:740:9: note: in expansion of macro 'with'
     740 |         with (auto _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl))        \
         |         ^~~~
   include/linux/uaccess.h:755:9: note: in expansion of macro '__scoped_user_access'
     755 |         __scoped_user_access(read, usrc, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:767:9: note: in expansion of macro 'scoped_user_read_access_size'
     767 |         scoped_user_read_access_size(usrc, sizeof(*(usrc)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:831:9: note: in expansion of macro 'scoped_user_read_access'
     831 |         scoped_user_read_access(_tmpsrc, efault)                \
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/futex.h:288:16: note: in expansion of macro 'get_user_inline'
     288 |         return get_user_inline(*dest, from);
         |                ^~~~~~~~~~~~~~~
   In file included from include/linux/compiler_types.h:173,
                    from <command-line>:
   include/linux/compiler-gcc.h:118:33: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
     118 | #define __diag(s)               _Pragma(__diag_str(GCC diagnostic s))
         |                                 ^~~~~~~
   include/linux/compiler-gcc.h:129:9: note: in expansion of macro '__diag'
     129 |         __diag(__diag_GCC_ignore option)
         |         ^~~~~~
   include/linux/uaccess.h:742:31: note: in expansion of macro '__diag_ignore_all'
     742 |                 __diag_push() __diag_ignore_all("-Wshadow", "uptr is readonly copy")    \
         |                               ^~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:755:9: note: in expansion of macro '__scoped_user_access'
     755 |         __scoped_user_access(read, usrc, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:767:9: note: in expansion of macro 'scoped_user_read_access_size'
     767 |         scoped_user_read_access_size(usrc, sizeof(*(usrc)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:831:9: note: in expansion of macro 'scoped_user_read_access'
     831 |         scoped_user_read_access(_tmpsrc, efault)                \
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/futex.h:288:16: note: in expansion of macro 'get_user_inline'
     288 |         return get_user_inline(*dest, from);
         |                ^~~~~~~~~~~~~~~
   In file included from include/asm-generic/div64.h:27,
                    from ./arch/nios2/include/generated/asm/div64.h:1,
                    from include/linux/math.h:6,
                    from include/linux/math64.h:6,
                    from include/linux/time.h:6,
                    from include/linux/compat.h:10,
                    from kernel/futex/core.c:34:
>> include/linux/uaccess.h:743:90: error: '_tmpptr' undeclared (first use in this function)
     743 |                 and_with (const auto uptr __cleanup(__scoped_user_##mode##_access_end) = _tmpptr) \
         |                                                                                          ^~~~~~~
   include/linux/compiler.h:396:14: note: in definition of macro 'and_with'
     396 |         for (declaration; !_with_done; _with_done = true)
         |              ^~~~~~~~~~~
   include/linux/uaccess.h:755:9: note: in expansion of macro '__scoped_user_access'
     755 |         __scoped_user_access(read, usrc, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:767:9: note: in expansion of macro 'scoped_user_read_access_size'
     767 |         scoped_user_read_access_size(usrc, sizeof(*(usrc)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:831:9: note: in expansion of macro 'scoped_user_read_access'
     831 |         scoped_user_read_access(_tmpsrc, efault)                \
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/futex.h:288:16: note: in expansion of macro 'get_user_inline'
     288 |         return get_user_inline(*dest, from);
         |                ^~~~~~~~~~~~~~~
   include/linux/uaccess.h:743:90: note: each undeclared identifier is reported only once for each function it appears in
     743 |                 and_with (const auto uptr __cleanup(__scoped_user_##mode##_access_end) = _tmpptr) \
         |                                                                                          ^~~~~~~
   include/linux/compiler.h:396:14: note: in definition of macro 'and_with'
     396 |         for (declaration; !_with_done; _with_done = true)
         |              ^~~~~~~~~~~
   include/linux/uaccess.h:755:9: note: in expansion of macro '__scoped_user_access'
     755 |         __scoped_user_access(read, usrc, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:767:9: note: in expansion of macro 'scoped_user_read_access_size'
     767 |         scoped_user_read_access_size(usrc, sizeof(*(usrc)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:831:9: note: in expansion of macro 'scoped_user_read_access'
     831 |         scoped_user_read_access(_tmpsrc, efault)                \
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/futex.h:288:16: note: in expansion of macro 'get_user_inline'
     288 |         return get_user_inline(*dest, from);
         |                ^~~~~~~~~~~~~~~
>> include/linux/compiler.h:396:28: error: '_with_done' undeclared (first use in this function)
     396 |         for (declaration; !_with_done; _with_done = true)
         |                            ^~~~~~~~~~
   include/linux/uaccess.h:743:17: note: in expansion of macro 'and_with'
     743 |                 and_with (const auto uptr __cleanup(__scoped_user_##mode##_access_end) = _tmpptr) \
         |                 ^~~~~~~~
   include/linux/uaccess.h:755:9: note: in expansion of macro '__scoped_user_access'
     755 |         __scoped_user_access(read, usrc, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:767:9: note: in expansion of macro 'scoped_user_read_access_size'
     767 |         scoped_user_read_access_size(usrc, sizeof(*(usrc)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:831:9: note: in expansion of macro 'scoped_user_read_access'
     831 |         scoped_user_read_access(_tmpsrc, efault)                \
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/futex.h:288:16: note: in expansion of macro 'get_user_inline'
     288 |         return get_user_inline(*dest, from);
         |                ^~~~~~~~~~~~~~~
   kernel/futex/core.c: In function 'get_futex_key':
>> include/linux/uaccess.h:740:20: warning: unused variable '_tmpptr' [-Wunused-variable]
     740 |         with (auto _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl))        \
         |                    ^~~~~~~
   include/linux/compiler.h:396:14: note: in definition of macro 'and_with'
     396 |         for (declaration; !_with_done; _with_done = true)
         |              ^~~~~~~~~~~
   include/linux/uaccess.h:740:9: note: in expansion of macro 'with'
     740 |         with (auto _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl))        \
         |         ^~~~
   include/linux/uaccess.h:755:9: note: in expansion of macro '__scoped_user_access'
     755 |         __scoped_user_access(read, usrc, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:767:9: note: in expansion of macro 'scoped_user_read_access_size'
     767 |         scoped_user_read_access_size(usrc, sizeof(*(usrc)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:831:9: note: in expansion of macro 'scoped_user_read_access'
     831 |         scoped_user_read_access(_tmpsrc, efault)                \
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/core.c:584:21: note: in expansion of macro 'get_user_inline'
     584 |                 if (get_user_inline(node, naddr))
         |                     ^~~~~~~~~~~~~~~
>> include/linux/compiler.h:396:9: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
     396 |         for (declaration; !_with_done; _with_done = true)
         |         ^~~
   include/linux/compiler.h:394:17: note: in expansion of macro 'and_with'
     394 |                 and_with (declaration)
         |                 ^~~~~~~~
   include/linux/uaccess.h:740:9: note: in expansion of macro 'with'
     740 |         with (auto _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl))        \
         |         ^~~~
   include/linux/uaccess.h:755:9: note: in expansion of macro '__scoped_user_access'
     755 |         __scoped_user_access(read, usrc, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:767:9: note: in expansion of macro 'scoped_user_read_access_size'
     767 |         scoped_user_read_access_size(usrc, sizeof(*(usrc)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:831:9: note: in expansion of macro 'scoped_user_read_access'
     831 |         scoped_user_read_access(_tmpsrc, efault)                \
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/core.c:584:21: note: in expansion of macro 'get_user_inline'
     584 |                 if (get_user_inline(node, naddr))
         |                     ^~~~~~~~~~~~~~~
   In file included from include/linux/compiler_types.h:173,
                    from <command-line>:
   include/linux/compiler-gcc.h:118:33: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
     118 | #define __diag(s)               _Pragma(__diag_str(GCC diagnostic s))
         |                                 ^~~~~~~
   include/linux/compiler-gcc.h:129:9: note: in expansion of macro '__diag'
     129 |         __diag(__diag_GCC_ignore option)
         |         ^~~~~~
   include/linux/uaccess.h:742:31: note: in expansion of macro '__diag_ignore_all'
     742 |                 __diag_push() __diag_ignore_all("-Wshadow", "uptr is readonly copy")    \
         |                               ^~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:755:9: note: in expansion of macro '__scoped_user_access'
     755 |         __scoped_user_access(read, usrc, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:767:9: note: in expansion of macro 'scoped_user_read_access_size'
     767 |         scoped_user_read_access_size(usrc, sizeof(*(usrc)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:831:9: note: in expansion of macro 'scoped_user_read_access'
     831 |         scoped_user_read_access(_tmpsrc, efault)                \
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/core.c:584:21: note: in expansion of macro 'get_user_inline'
     584 |                 if (get_user_inline(node, naddr))
         |                     ^~~~~~~~~~~~~~~
   In file included from include/asm-generic/div64.h:27,
                    from ./arch/nios2/include/generated/asm/div64.h:1,
                    from include/linux/math.h:6,
                    from include/linux/math64.h:6,
                    from include/linux/time.h:6,
                    from include/linux/compat.h:10,
                    from kernel/futex/core.c:34:
>> include/linux/uaccess.h:743:90: error: '_tmpptr' undeclared (first use in this function)
     743 |                 and_with (const auto uptr __cleanup(__scoped_user_##mode##_access_end) = _tmpptr) \
         |                                                                                          ^~~~~~~
   include/linux/compiler.h:396:14: note: in definition of macro 'and_with'
     396 |         for (declaration; !_with_done; _with_done = true)
         |              ^~~~~~~~~~~
   include/linux/uaccess.h:755:9: note: in expansion of macro '__scoped_user_access'
     755 |         __scoped_user_access(read, usrc, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:767:9: note: in expansion of macro 'scoped_user_read_access_size'
     767 |         scoped_user_read_access_size(usrc, sizeof(*(usrc)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:831:9: note: in expansion of macro 'scoped_user_read_access'
     831 |         scoped_user_read_access(_tmpsrc, efault)                \
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/core.c:584:21: note: in expansion of macro 'get_user_inline'
     584 |                 if (get_user_inline(node, naddr))
         |                     ^~~~~~~~~~~~~~~
>> include/linux/compiler.h:396:28: error: '_with_done' undeclared (first use in this function)
     396 |         for (declaration; !_with_done; _with_done = true)
         |                            ^~~~~~~~~~
   include/linux/uaccess.h:743:17: note: in expansion of macro 'and_with'
     743 |                 and_with (const auto uptr __cleanup(__scoped_user_##mode##_access_end) = _tmpptr) \
         |                 ^~~~~~~~
   include/linux/uaccess.h:755:9: note: in expansion of macro '__scoped_user_access'
     755 |         __scoped_user_access(read, usrc, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:767:9: note: in expansion of macro 'scoped_user_read_access_size'
     767 |         scoped_user_read_access_size(usrc, sizeof(*(usrc)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:831:9: note: in expansion of macro 'scoped_user_read_access'
     831 |         scoped_user_read_access(_tmpsrc, efault)                \
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/core.c:584:21: note: in expansion of macro 'get_user_inline'
     584 |                 if (get_user_inline(node, naddr))
         |                     ^~~~~~~~~~~~~~~
>> include/linux/uaccess.h:740:20: warning: unused variable '_tmpptr' [-Wunused-variable]
     740 |         with (auto _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl))        \
         |                    ^~~~~~~
   include/linux/compiler.h:396:14: note: in definition of macro 'and_with'
     396 |         for (declaration; !_with_done; _with_done = true)
         |              ^~~~~~~~~~~
   include/linux/uaccess.h:740:9: note: in expansion of macro 'with'
     740 |         with (auto _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl))        \
         |         ^~~~
   include/linux/uaccess.h:778:9: note: in expansion of macro '__scoped_user_access'
     778 |         __scoped_user_access(write, udst, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:790:9: note: in expansion of macro 'scoped_user_write_access_size'
     790 |         scoped_user_write_access_size(udst, sizeof(*(udst)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:856:9: note: in expansion of macro 'scoped_user_write_access'
     856 |         scoped_user_write_access(_tmpdst, efault)               \
         |         ^~~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/core.c:604:37: note: in expansion of macro 'put_user_inline'
     604 |                 if (node_updated && put_user_inline(node, naddr))
         |                                     ^~~~~~~~~~~~~~~
>> include/linux/compiler.h:396:9: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
     396 |         for (declaration; !_with_done; _with_done = true)
         |         ^~~
   include/linux/compiler.h:394:17: note: in expansion of macro 'and_with'
     394 |                 and_with (declaration)
         |                 ^~~~~~~~
   include/linux/uaccess.h:740:9: note: in expansion of macro 'with'
     740 |         with (auto _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl))        \
         |         ^~~~
   include/linux/uaccess.h:778:9: note: in expansion of macro '__scoped_user_access'
     778 |         __scoped_user_access(write, udst, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:790:9: note: in expansion of macro 'scoped_user_write_access_size'
     790 |         scoped_user_write_access_size(udst, sizeof(*(udst)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:856:9: note: in expansion of macro 'scoped_user_write_access'
     856 |         scoped_user_write_access(_tmpdst, efault)               \
         |         ^~~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/core.c:604:37: note: in expansion of macro 'put_user_inline'
     604 |                 if (node_updated && put_user_inline(node, naddr))
         |                                     ^~~~~~~~~~~~~~~
   In file included from include/linux/compiler_types.h:173,
                    from <command-line>:
   include/linux/compiler-gcc.h:118:33: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
     118 | #define __diag(s)               _Pragma(__diag_str(GCC diagnostic s))
         |                                 ^~~~~~~
   include/linux/compiler-gcc.h:129:9: note: in expansion of macro '__diag'
     129 |         __diag(__diag_GCC_ignore option)
         |         ^~~~~~
   include/linux/uaccess.h:742:31: note: in expansion of macro '__diag_ignore_all'
     742 |                 __diag_push() __diag_ignore_all("-Wshadow", "uptr is readonly copy")    \
         |                               ^~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:778:9: note: in expansion of macro '__scoped_user_access'
     778 |         __scoped_user_access(write, udst, size, elbl)
         |         ^~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:790:9: note: in expansion of macro 'scoped_user_write_access_size'
     790 |         scoped_user_write_access_size(udst, sizeof(*(udst)), elbl)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/uaccess.h:856:9: note: in expansion of macro 'scoped_user_write_access'
     856 |         scoped_user_write_access(_tmpdst, efault)               \
         |         ^~~~~~~~~~~~~~~~~~~~~~~~
   kernel/futex/core.c:604:37: note: in expansion of macro 'put_user_inline'
     604 |                 if (node_updated && put_user_inline(node, naddr))
         |                                     ^~~~~~~~~~~~~~~
..

vim +/_tmpptr +743 include/linux/uaccess.h

   689	
   690	/**
   691	 * __scoped_user_access - Open a scope for user access
   692	 * @mode:	The mode of the access class (read, write, rw)
   693	 * @uptr:	The pointer to access user space memory
   694	 * @size:	Size of the access
   695	 * @elbl:	Error label to goto when the access region is rejected. It
   696	 *		must be placed outside the scope
   697	 *
   698	 * If the user access function inside the scope requires a fault label, it
   699	 * can use @elbl or a different label outside the scope, which requires
   700	 * that user access which is implemented with ASM GOTO has been properly
   701	 * wrapped. See unsafe_get_user() for reference.
   702	 *
   703	 *	scoped_user_rw_access(ptr, efault) {
   704	 *		unsafe_get_user(rval, &ptr->rval, efault);
   705	 *		unsafe_put_user(wval, &ptr->wval, efault);
   706	 *	}
   707	 *	return 0;
   708	 *  efault:
   709	 *	return -EFAULT;
   710	 *
   711	 * The scope is internally implemented as a autoterminating nested for()
   712	 * loop, which can be left with 'return', 'break' and 'goto' at any
   713	 * point.
   714	 *
   715	 * When the scope is left user_##@_mode##_access_end() is automatically
   716	 * invoked.
   717	 *
   718	 * When the architecture supports masked user access and the access region
   719	 * which is determined by @uptr and @size is not a valid user space
   720	 * address, i.e. < TASK_SIZE, the scope sets the pointer to a faulting user
   721	 * space address and does not terminate early. This optimizes for the good
   722	 * case and lets the performance uncritical bad case go through the fault.
   723	 *
   724	 * The eventual modification of the pointer is limited to the scope.
   725	 * Outside of the scope the original pointer value is unmodified, so that
   726	 * the original pointer value is available for diagnostic purposes in an
   727	 * out of scope fault path.
   728	 *
   729	 * Nesting scoped user access into a user access scope is invalid and fails
   730	 * the build. Nesting into other guards, e.g. pagefault is safe.
   731	 *
   732	 * The masked variant does not check the size of the access and relies on a
   733	 * mapping hole (e.g. guard page) to catch an out of range pointer, the
   734	 * first access to user memory inside the scope has to be within
   735	 * @uptr ... @uptr + PAGE_SIZE - 1
   736	 *
   737	 * Don't use directly. Use scoped_masked_user_$MODE_access() instead.
   738	 */
   739	#define __scoped_user_access(mode, uptr, size, elbl)					\
 > 740		with (auto _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl))	\
   741			/* Force modified pointer usage within the scope */			\
   742			__diag_push() __diag_ignore_all("-Wshadow", "uptr is readonly copy")	\
 > 743			and_with (const auto uptr __cleanup(__scoped_user_##mode##_access_end) = _tmpptr) \
   744			__diag_pop()
   745	

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