include/linux/build_bug.h:78:41: error: static assertion failed: "sizeof(typeof_member(union access_masks_all, masks)) == sizeof(typeof_member(union access_masks_all, all))"
kernel test robot
build bottree: https://git.kernel.org/pub/scm/linux/kernel/git/mic/linux.git next head: 42d105958e98c6ae8fd6d62b38727444d25e735d commit: 8dcfb7e52f844e73413d7f743945e135747a1048 [16/24] landlock: Control pathname UNIX domain socket resolution by path config: m68k-allmodconfig (https://download.01.org/0day-ci/archive/20260326/[email protected]/config) compiler: m68k-linux-gcc (GCC) 15.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260326/[email protected]/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 protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All errors (new ones prefixed by >>):
In file included from include/linux/bits.h:30,
from security/landlock/setup.c:9:
>> include/linux/build_bug.h:78:41: error: static assertion failed: "sizeof(typeof_member(union access_masks_all, masks)) == sizeof(typeof_member(union access_masks_all, all))"
78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
| ^~~~~~~~~~~~~~
include/linux/build_bug.h:77:34: note: in expansion of macro '__static_assert'
77 | #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
| ^~~~~~~~~~~~~~~
security/landlock/access.h:61:1: note: in expansion of macro 'static_assert'
61 | static_assert(sizeof(typeof_member(union access_masks_all, masks)) ==
| ^~~~~~~~~~~~~vim +78 include/linux/build_bug.h
bc6245e5efd70c Ian Abbott 2017-07-10 60 6bab69c65013be Rasmus Villemoes 2019-03-07 61 /** 6bab69c65013be Rasmus Villemoes 2019-03-07 62 * static_assert - check integer constant expression at build time 6bab69c65013be Rasmus Villemoes 2019-03-07 63 * 6bab69c65013be Rasmus Villemoes 2019-03-07 64 * static_assert() is a wrapper for the C11 _Static_assert, with a 6bab69c65013be Rasmus Villemoes 2019-03-07 65 * little macro magic to make the message optional (defaulting to the 6bab69c65013be Rasmus Villemoes 2019-03-07 66 * stringification of the tested expression). 6bab69c65013be Rasmus Villemoes 2019-03-07 67 * 6bab69c65013be Rasmus Villemoes 2019-03-07 68 * Contrary to BUILD_BUG_ON(), static_assert() can be used at global 6bab69c65013be Rasmus Villemoes 2019-03-07 69 * scope, but requires the expression to be an integer constant 6bab69c65013be Rasmus Villemoes 2019-03-07 70 * expression (i.e., it is not enough that __builtin_constant_p() is 6bab69c65013be Rasmus Villemoes 2019-03-07 71 * true for expr). 6bab69c65013be Rasmus Villemoes 2019-03-07 72 * 6bab69c65013be Rasmus Villemoes 2019-03-07 73 * Also note that BUILD_BUG_ON() fails the build if the condition is 6bab69c65013be Rasmus Villemoes 2019-03-07 74 * true, while static_assert() fails the build if the expression is 6bab69c65013be Rasmus Villemoes 2019-03-07 75 * false. 6bab69c65013be Rasmus Villemoes 2019-03-07 76 */ 6bab69c65013be Rasmus Villemoes 2019-03-07 77 #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
6bab69c65013be Rasmus Villemoes 2019-03-07 @78 #define __static_assert(expr, msg, ...) _Static_assert(expr, msg) 6bab69c65013be Rasmus Villemoes 2019-03-07 7907a368b3f55a79 Maxim Levitsky 2022-10-25 80
:::::: The code at line 78 was first introduced by commit
:::::: 6bab69c65013bed5fce9f101a64a84d0385b3946 build_bug.h: add wrapper for _Static_assert
:::::: TO: Rasmus Villemoes <[email protected]> :::::: CC: Linus Torvalds <[email protected]>
Signature · 2 lines
0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
Quoted 51 lines · kernel test robot
tree: https://git.kernel.org/pub/scm/linux/kernel/git/mic/linux.git next head: 42d105958e98c6ae8fd6d62b38727444d25e735d commit: 8dcfb7e52f844e73413d7f743945e135747a1048 [16/24] landlock: Control pathname UNIX domain socket resolution by path config: m68k-allmodconfig (https://download.01.org/0day-ci/archive/20260326/[email protected]/config) compiler: m68k-linux-gcc (GCC) 15.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260326/[email protected]/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 protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/All errors (new ones prefixed by >>):
In file included from
include/linux/bits.h:30,
fromsecurity/landlock/setup.c:9:Quoted 1 line
Quoted 1 line
include/linux/build_bug.h:78:41: error: static assertion failed: "sizeof(typeof_member(union access_masks_all, masks))==sizeof(typeof_member(union access_masks_all, all))"78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg) | ^~~~~~~~~~~~~~ include/linux/build_bug.h:77:34: note: in expansion of macro '__static_assert' 77 | #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr) | ^~~~~~~~~~~~~~~ security/landlock/access.h:61:1: note: in expansion of macro 'static_assert' 61 | static_assert(sizeof(typeof_member(union access_masks_all, masks)) == | ^~~~~~~~~~~~~vim +78
include/linux/build_bug.hbc6245e5efd70c Ian Abbott 2017-07-10 60 6bab69c65013be Rasmus Villemoes 2019-03-07 61 /** 6bab69c65013be Rasmus Villemoes 2019-03-07 62 * static_assert - check integer constant expression at build time 6bab69c65013be Rasmus Villemoes 2019-03-07 63 * 6bab69c65013be Rasmus Villemoes 2019-03-07 64 * static_assert() is a wrapper for the C11 _Static_assert, with a 6bab69c65013be Rasmus Villemoes 2019-03-07 65 * little macro magic to make the message optional (defaulting to the 6bab69c65013be Rasmus Villemoes 2019-03-07 66 * stringification of the tested expression). 6bab69c65013be Rasmus Villemoes 2019-03-07 67 * 6bab69c65013be Rasmus Villemoes 2019-03-07 68 * Contrary to BUILD_BUG_ON(), static_assert() can be used at global 6bab69c65013be Rasmus Villemoes 2019-03-07 69 * scope, but requires the expression to be an integer constant 6bab69c65013be Rasmus Villemoes 2019-03-07 70 * expression (i.e., it is not enough that __builtin_constant_p() is 6bab69c65013be Rasmus Villemoes 2019-03-07 71 * true for expr). 6bab69c65013be Rasmus Villemoes 2019-03-07 72 * 6bab69c65013be Rasmus Villemoes 2019-03-07 73 * Also note that BUILD_BUG_ON() fails the build if the condition is 6bab69c65013be Rasmus Villemoes 2019-03-07 74 * true, while static_assert() fails the build if the expression is 6bab69c65013be Rasmus Villemoes 2019-03-07 75 * false. 6bab69c65013be Rasmus Villemoes 2019-03-07 76 */ 6bab69c65013be Rasmus Villemoes 2019-03-07 77 #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
6bab69c65013beRasmus Villemoes 2019-03-07 @78 #define__static_assert(expr, msg, ...)_Static_assert(expr, msg)6bab69c65013beRasmus Villemoes 2019-03-07 7907a368b3f55a79Maxim Levitsky 2022-10-25 80
Quoted 9 lines
:::::: The code at line 78 was first introduced by commit
::::::6bab69c65013bed5fce9f101a64a84d0385b3946build_bug.h: add wrapper for_Static_assert:::::: TO: Rasmus Villemoes <[email protected]> :::::: CC: Linus Torvalds <[email protected]>
Signature · 2 lines
0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
Hmm, intuitively, it might have been introduced by the Unix Connect Control patch set which was recently added to mic-next:
m68k is a 32-bit architecture.
We are introducing the 17th filesystem access bit, and changing the size of access_mask_t from u16 to u32 there,
The relevant code is:
```
/* Ruleset access masks. */
struct access_masks {
access_mask_t fs : LANDLOCK_NUM_ACCESS_FS; /* 17 */
access_mask_t net : LANDLOCK_NUM_ACCESS_NET; /* 2 */
access_mask_t scope : LANDLOCK_NUM_SCOPE; /* 2 */
};
union access_masks_all {
struct access_masks masks;
u32 all;
};
/* Makes sure all fields are covered. */
static_assert(sizeof(typeof_member(union access_masks_all, masks)) ==
sizeof(typeof_member(union access_masks_all, all)));
```Intuitively, it is not clear why that static assertion suddenly fails; 17+2+2 is still well below 32. I see that the C standard does not give strong guarantees about the memory layout of this, though.
I'll need to have a closer look later. I can imagine that there is an attribute or such that will hint the compiler to pack these bits tighter.
—Günther