Re: [PATCH v2] kernfs: recheck of->released after acquiring the active reference
From: kernel test robot
Date: Sun Aug 23 2026 - 08:27:52 EST
Hi Fan,
kernel test robot noticed the following build errors:
[auto build test ERROR on driver-core/driver-core-testing]
[also build test ERROR on driver-core/driver-core-next driver-core/driver-core-linus linus/master v7.2 next-20260821]
[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/Fan-Wu/kernfs-recheck-of-released-after-acquiring-the-active-reference/20260821-050720
base: driver-core/driver-core-testing
patch link: https://lore.kernel.org/r/20260821050720.14848-1-fanwu01%40zju.edu.cn
patch subject: [PATCH v2] kernfs: recheck of->released after acquiring the active reference
config: alpha-allnoconfig (https://download.01.org/0day-ci/archive/20260823/202608230046.Ixvo8Av6-lkp@xxxxxxxxx/config)
compiler: alpha-linux-gcc (GCC) 16.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260823/202608230046.Ixvo8Av6-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/202608230046.Ixvo8Av6-lkp@xxxxxxxxx/
All errors (new ones prefixed by >>):
| ^~~~~~~~~~~~~
include/asm-generic/rwonce.h:49:9: note: in expansion of macro 'compiletime_assert_rwonce_type'
49 | compiletime_assert_rwonce_type(x); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/kernfs/file.c:76:22: note: in expansion of macro 'READ_ONCE'
76 | if (unlikely(READ_ONCE(of->released))) {
| ^~~~~~~~~
include/linux/compiler_types.h:663:45: error: 'sizeof' applied to a bit-field
663 | (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || \
| ^
include/linux/compiler.h:77:45: note: in definition of macro 'unlikely'
77 | # define unlikely(x) __builtin_expect(!!(x), 0)
| ^
include/linux/compiler_types.h:690:9: note: in expansion of macro '__compiletime_assert'
690 | __compiletime_assert(condition, msg, prefix, suffix)
| ^~~~~~~~~~~~~~~~~~~~
include/linux/compiler_types.h:702:9: note: in expansion of macro '_compiletime_assert'
702 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:36:9: note: in expansion of macro 'compiletime_assert'
36 | compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
| ^~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:36:28: note: in expansion of macro '__native_word'
36 | compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
| ^~~~~~~~~~~~~
include/asm-generic/rwonce.h:49:9: note: in expansion of macro 'compiletime_assert_rwonce_type'
49 | compiletime_assert_rwonce_type(x); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/kernfs/file.c:76:22: note: in expansion of macro 'READ_ONCE'
76 | if (unlikely(READ_ONCE(of->released))) {
| ^~~~~~~~~
include/linux/compiler_types.h:664:16: error: 'sizeof' applied to a bit-field
664 | sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
| ^
include/linux/compiler.h:77:45: note: in definition of macro 'unlikely'
77 | # define unlikely(x) __builtin_expect(!!(x), 0)
| ^
include/linux/compiler_types.h:690:9: note: in expansion of macro '__compiletime_assert'
690 | __compiletime_assert(condition, msg, prefix, suffix)
| ^~~~~~~~~~~~~~~~~~~~
include/linux/compiler_types.h:702:9: note: in expansion of macro '_compiletime_assert'
702 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:36:9: note: in expansion of macro 'compiletime_assert'
36 | compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
| ^~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:36:28: note: in expansion of macro '__native_word'
36 | compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
| ^~~~~~~~~~~~~
include/asm-generic/rwonce.h:49:9: note: in expansion of macro 'compiletime_assert_rwonce_type'
49 | compiletime_assert_rwonce_type(x); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/kernfs/file.c:76:22: note: in expansion of macro 'READ_ONCE'
76 | if (unlikely(READ_ONCE(of->released))) {
| ^~~~~~~~~
include/linux/compiler_types.h:664:44: error: 'sizeof' applied to a bit-field
664 | sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
| ^
include/linux/compiler.h:77:45: note: in definition of macro 'unlikely'
77 | # define unlikely(x) __builtin_expect(!!(x), 0)
| ^
include/linux/compiler_types.h:690:9: note: in expansion of macro '__compiletime_assert'
690 | __compiletime_assert(condition, msg, prefix, suffix)
| ^~~~~~~~~~~~~~~~~~~~
include/linux/compiler_types.h:702:9: note: in expansion of macro '_compiletime_assert'
702 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:36:9: note: in expansion of macro 'compiletime_assert'
36 | compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
| ^~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:36:28: note: in expansion of macro '__native_word'
36 | compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
| ^~~~~~~~~~~~~
include/asm-generic/rwonce.h:49:9: note: in expansion of macro 'compiletime_assert_rwonce_type'
49 | compiletime_assert_rwonce_type(x); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/kernfs/file.c:76:22: note: in expansion of macro 'READ_ONCE'
76 | if (unlikely(READ_ONCE(of->released))) {
| ^~~~~~~~~
include/asm-generic/rwonce.h:36:54: error: 'sizeof' applied to a bit-field
36 | compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
| ^
include/linux/compiler.h:77:45: note: in definition of macro 'unlikely'
77 | # define unlikely(x) __builtin_expect(!!(x), 0)
| ^
include/linux/compiler_types.h:690:9: note: in expansion of macro '__compiletime_assert'
690 | __compiletime_assert(condition, msg, prefix, suffix)
| ^~~~~~~~~~~~~~~~~~~~
include/linux/compiler_types.h:702:9: note: in expansion of macro '_compiletime_assert'
702 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:36:9: note: in expansion of macro 'compiletime_assert'
36 | compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
| ^~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:49:9: note: in expansion of macro 'compiletime_assert_rwonce_type'
49 | compiletime_assert_rwonce_type(x); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/kernfs/file.c:76:22: note: in expansion of macro 'READ_ONCE'
76 | if (unlikely(READ_ONCE(of->released))) {
| ^~~~~~~~~
>> fs/kernfs/file.c:76:32: error: 'typeof' applied to a bit-field
76 | if (unlikely(READ_ONCE(of->released))) {
| ^~
include/linux/compiler.h:77:45: note: in definition of macro 'unlikely'
77 | # define unlikely(x) __builtin_expect(!!(x), 0)
| ^
include/asm-generic/rwonce.h:44:43: note: in expansion of macro '__unqual_scalar_typeof'
44 | #define __READ_ONCE(x) (*(const volatile __unqual_scalar_typeof(x) *)&(x))
| ^~~~~~~~~~~~~~~~~~~~~~
include/asm-generic/rwonce.h:50:9: note: in expansion of macro '__READ_ONCE'
50 | __READ_ONCE(x); \
| ^~~~~~~~~~~
fs/kernfs/file.c:76:22: note: in expansion of macro 'READ_ONCE'
76 | if (unlikely(READ_ONCE(of->released))) {
| ^~~~~~~~~
include/asm-generic/rwonce.h:44:71: error: cannot take address of bit-field 'released'
44 | #define __READ_ONCE(x) (*(const volatile __unqual_scalar_typeof(x) *)&(x))
| ^
include/linux/compiler.h:77:45: note: in definition of macro 'unlikely'
77 | # define unlikely(x) __builtin_expect(!!(x), 0)
| ^
include/asm-generic/rwonce.h:50:9: note: in expansion of macro '__READ_ONCE'
50 | __READ_ONCE(x); \
| ^~~~~~~~~~~
fs/kernfs/file.c:76:22: note: in expansion of macro 'READ_ONCE'
76 | if (unlikely(READ_ONCE(of->released))) {
| ^~~~~~~~~
vim +/typeof +76 fs/kernfs/file.c
65
66 /* Get active reference to kernfs node for an open file */
67 static struct kernfs_open_file *kernfs_get_active_of(struct kernfs_open_file *of)
68 {
69 if (!kernfs_get_active(of->kn))
70 return NULL;
71
72 /*
73 * A successful active reference prevents a new drain and orders this
74 * check after an earlier reactivation.
75 */
> 76 if (unlikely(READ_ONCE(of->released))) {
77 kernfs_put_active(of->kn);
78 return NULL;
79 }
80
81 return of;
82 }
83
--
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