* Re: [PATCH][next] fortify: add branch hints on unlikely fortify_panic paths
2025-06-25 16:12 [PATCH][next] fortify: add branch hints on unlikely fortify_panic paths Colin Ian King
@ 2025-06-27 0:14 ` kernel test robot
2025-06-27 1:05 ` kernel test robot
2025-06-27 16:36 ` Kees Cook
2 siblings, 0 replies; 5+ messages in thread
From: kernel test robot @ 2025-06-27 0:14 UTC (permalink / raw)
To: Colin Ian King, Kees Cook, linux-hardening
Cc: llvm, oe-kbuild-all, kernel-janitors, linux-kernel
Hi Colin,
kernel test robot noticed the following build errors:
[auto build test ERROR on kees/for-next/hardening]
[also build test ERROR on kees/for-next/pstore kees/for-next/kspp linus/master v6.16-rc3 next-20250626]
[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/Colin-Ian-King/fortify-add-branch-hints-on-unlikely-fortify_panic-paths/20250626-001527
base: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/hardening
patch link: https://lore.kernel.org/r/20250625161221.295575-1-colin.i.king%40gmail.com
patch subject: [PATCH][next] fortify: add branch hints on unlikely fortify_panic paths
config: x86_64-buildonly-randconfig-001-20250627 (https://download.01.org/0day-ci/archive/20250627/202506270832.QJ2ekScw-lkp@intel.com/config)
compiler: clang version 20.1.7 (https://github.com/llvm/llvm-project 6146a88f60492b520a36f8f8f3231e15f3cc6082)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250627/202506270832.QJ2ekScw-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506270832.QJ2ekScw-lkp@intel.com/
All error/warnings (new ones prefixed by >>):
In file included from scripts/mod/devicetable-offsets.c:3:
In file included from include/linux/mod_devicetable.h:14:
In file included from include/linux/uuid.h:11:
In file included from include/linux/string.h:392:
>> include/linux/fortify-string.h:596:6: warning: non-constant static local variable in inline function may be different in different files [-Wstatic-local-in-inline]
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^
include/linux/compiler.h:47:24: note: expanded from macro 'unlikely'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^
include/linux/compiler.h:24:4: note: expanded from macro '__branch_check__'
24 | static struct ftrace_likely_data \
| ^
In file included from scripts/mod/devicetable-offsets.c:3:
In file included from include/linux/mod_devicetable.h:14:
In file included from include/linux/uuid.h:11:
In file included from include/linux/string.h:392:
include/linux/fortify-string.h:598:11: warning: non-constant static local variable in inline function may be different in different files [-Wstatic-local-in-inline]
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^
include/linux/compiler.h:47:24: note: expanded from macro 'unlikely'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^
include/linux/compiler.h:24:4: note: expanded from macro '__branch_check__'
24 | static struct ftrace_likely_data \
| ^
2 warnings generated.
--
In file included from lib/locking-selftest.c:14:
In file included from include/linux/rwsem.h:15:
In file included from include/linux/spinlock.h:59:
In file included from include/linux/irqflags.h:18:
In file included from arch/x86/include/asm/irqflags.h:102:
In file included from arch/x86/include/asm/paravirt.h:21:
In file included from include/linux/cpumask.h:12:
In file included from include/linux/bitmap.h:13:
In file included from include/linux/string.h:392:
>> include/linux/fortify-string.h:596:6: warning: non-constant static local variable in inline function may be different in different files [-Wstatic-local-in-inline]
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^
include/linux/compiler.h:47:24: note: expanded from macro 'unlikely'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^
include/linux/compiler.h:24:4: note: expanded from macro '__branch_check__'
24 | static struct ftrace_likely_data \
| ^
In file included from lib/locking-selftest.c:14:
In file included from include/linux/rwsem.h:15:
In file included from include/linux/spinlock.h:59:
In file included from include/linux/irqflags.h:18:
In file included from arch/x86/include/asm/irqflags.h:102:
In file included from arch/x86/include/asm/paravirt.h:21:
In file included from include/linux/cpumask.h:12:
In file included from include/linux/bitmap.h:13:
In file included from include/linux/string.h:392:
include/linux/fortify-string.h:598:11: warning: non-constant static local variable in inline function may be different in different files [-Wstatic-local-in-inline]
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^
include/linux/compiler.h:47:24: note: expanded from macro 'unlikely'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^
include/linux/compiler.h:24:4: note: expanded from macro '__branch_check__'
24 | static struct ftrace_likely_data \
| ^
lib/locking-selftest.c:2510:1: warning: unused function 'class_HARDIRQ_lock_ptr' [-Wunused-function]
2510 | DEFINE_LOCK_GUARD_0(HARDIRQ, HARDIRQ_ENTER(), HARDIRQ_EXIT())
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/cleanup.h:432:49: note: expanded from macro 'DEFINE_LOCK_GUARD_0'
432 | __DEFINE_CLASS_IS_CONDITIONAL(_name, false); \
| ^
433 | __DEFINE_UNLOCK_GUARD(_name, void, _unlock, __VA_ARGS__) \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/cleanup.h:406:10: note: expanded from macro '\
__DEFINE_UNLOCK_GUARD'
406 | \
| ^
407 | __DEFINE_GUARD_LOCK_PTR(_name, &_T->lock)
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/cleanup.h:314:23: note: expanded from macro '\
__DEFINE_GUARD_LOCK_PTR'
314 | static inline void * class_##_name##_lock_ptr(class_##_name##_t *_T) \
| ^~~~~~~~~~~~~~~~~~~~~~~~
<scratch space>:21:1: note: expanded from here
21 | class_HARDIRQ_lock_ptr
| ^~~~~~~~~~~~~~~~~~~~~~
lib/locking-selftest.c:2511:1: warning: unused function 'class_NOTTHREADED_HARDIRQ_lock_ptr' [-Wunused-function]
2511 | DEFINE_LOCK_GUARD_0(NOTTHREADED_HARDIRQ,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2512 | do {
| ~~~~
2513 | local_irq_disable();
| ~~~~~~~~~~~~~~~~~~~~
2514 | __irq_enter();
| ~~~~~~~~~~~~~~
2515 | WARN_ON(!in_irq());
| ~~~~~~~~~~~~~~~~~~~
2516 | } while(0), HARDIRQ_EXIT())
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/cleanup.h:432:49: note: expanded from macro 'DEFINE_LOCK_GUARD_0'
432 | __DEFINE_CLASS_IS_CONDITIONAL(_name, false); \
| ^
433 | __DEFINE_UNLOCK_GUARD(_name, void, _unlock, __VA_ARGS__) \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/cleanup.h:406:10: note: expanded from macro '\
__DEFINE_UNLOCK_GUARD'
406 | \
| ^
407 | __DEFINE_GUARD_LOCK_PTR(_name, &_T->lock)
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/cleanup.h:314:23: note: expanded from macro '\
__DEFINE_GUARD_LOCK_PTR'
314 | static inline void * class_##_name##_lock_ptr(class_##_name##_t *_T) \
| ^~~~~~~~~~~~~~~~~~~~~~~~
<scratch space>:105:1: note: expanded from here
105 | class_NOTTHREADED_HARDIRQ_lock_ptr
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/locking-selftest.c:2517:1: warning: unused function 'class_SOFTIRQ_lock_ptr' [-Wunused-function]
2517 | DEFINE_LOCK_GUARD_0(SOFTIRQ, SOFTIRQ_ENTER(), SOFTIRQ_EXIT())
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/cleanup.h:432:49: note: expanded from macro 'DEFINE_LOCK_GUARD_0'
432 | __DEFINE_CLASS_IS_CONDITIONAL(_name, false); \
| ^
433 | __DEFINE_UNLOCK_GUARD(_name, void, _unlock, __VA_ARGS__) \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/cleanup.h:406:10: note: expanded from macro '\
__DEFINE_UNLOCK_GUARD'
406 | \
| ^
407 | __DEFINE_GUARD_LOCK_PTR(_name, &_T->lock)
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/cleanup.h:314:23: note: expanded from macro '\
__DEFINE_GUARD_LOCK_PTR'
314 | static inline void * class_##_name##_lock_ptr(class_##_name##_t *_T) \
| ^~~~~~~~~~~~~~~~~~~~~~~~
<scratch space>:125:1: note: expanded from here
125 | class_SOFTIRQ_lock_ptr
| ^~~~~~~~~~~~~~~~~~~~~~
lib/locking-selftest.c:2520:1: warning: unused function 'class_RCU_lock_ptr' [-Wunused-function]
--
In file included from lib/test_bitops.c:10:
In file included from include/linux/module.h:13:
In file included from include/linux/stat.h:19:
In file included from include/linux/time.h:60:
In file included from include/linux/time32.h:13:
In file included from include/linux/timex.h:67:
In file included from arch/x86/include/asm/timex.h:5:
In file included from arch/x86/include/asm/processor.h:19:
In file included from arch/x86/include/asm/cpuid/api.h:57:
In file included from arch/x86/include/asm/paravirt.h:21:
In file included from include/linux/cpumask.h:12:
In file included from include/linux/bitmap.h:13:
In file included from include/linux/string.h:392:
>> include/linux/fortify-string.h:596:6: error: non-constant static local variable in inline function may be different in different files [-Werror,-Wstatic-local-in-inline]
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^
include/linux/compiler.h:47:24: note: expanded from macro 'unlikely'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^
include/linux/compiler.h:24:4: note: expanded from macro '__branch_check__'
24 | static struct ftrace_likely_data \
| ^
In file included from lib/test_bitops.c:10:
In file included from include/linux/module.h:13:
In file included from include/linux/stat.h:19:
In file included from include/linux/time.h:60:
In file included from include/linux/time32.h:13:
In file included from include/linux/timex.h:67:
In file included from arch/x86/include/asm/timex.h:5:
In file included from arch/x86/include/asm/processor.h:19:
In file included from arch/x86/include/asm/cpuid/api.h:57:
In file included from arch/x86/include/asm/paravirt.h:21:
In file included from include/linux/cpumask.h:12:
In file included from include/linux/bitmap.h:13:
In file included from include/linux/string.h:392:
include/linux/fortify-string.h:598:11: error: non-constant static local variable in inline function may be different in different files [-Werror,-Wstatic-local-in-inline]
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^
include/linux/compiler.h:47:24: note: expanded from macro 'unlikely'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^
include/linux/compiler.h:24:4: note: expanded from macro '__branch_check__'
24 | static struct ftrace_likely_data \
| ^
2 errors generated.
--
In file included from lib/test_maple_tree.c:10:
In file included from include/linux/maple_tree.h:12:
In file included from include/linux/rcupdate.h:26:
In file included from include/linux/irqflags.h:18:
In file included from arch/x86/include/asm/irqflags.h:102:
In file included from arch/x86/include/asm/paravirt.h:21:
In file included from include/linux/cpumask.h:12:
In file included from include/linux/bitmap.h:13:
In file included from include/linux/string.h:392:
>> include/linux/fortify-string.h:596:6: warning: non-constant static local variable in inline function may be different in different files [-Wstatic-local-in-inline]
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^
include/linux/compiler.h:47:24: note: expanded from macro 'unlikely'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^
include/linux/compiler.h:24:4: note: expanded from macro '__branch_check__'
24 | static struct ftrace_likely_data \
| ^
In file included from lib/test_maple_tree.c:10:
In file included from include/linux/maple_tree.h:12:
In file included from include/linux/rcupdate.h:26:
In file included from include/linux/irqflags.h:18:
In file included from arch/x86/include/asm/irqflags.h:102:
In file included from arch/x86/include/asm/paravirt.h:21:
In file included from include/linux/cpumask.h:12:
In file included from include/linux/bitmap.h:13:
In file included from include/linux/string.h:392:
include/linux/fortify-string.h:598:11: warning: non-constant static local variable in inline function may be different in different files [-Wstatic-local-in-inline]
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^
include/linux/compiler.h:47:24: note: expanded from macro 'unlikely'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^
include/linux/compiler.h:24:4: note: expanded from macro '__branch_check__'
24 | static struct ftrace_likely_data \
| ^
lib/test_maple_tree.c:212:26: warning: unused function 'not_empty' [-Wunused-function]
212 | static inline __init int not_empty(struct maple_node *node)
| ^~~~~~~~~
3 warnings generated.
--
In file included from lib/tests/stackinit_kunit.c:14:
In file included from include/kunit/test.h:22:
In file included from include/linux/kref.h:16:
In file included from include/linux/spinlock.h:59:
In file included from include/linux/irqflags.h:18:
In file included from arch/x86/include/asm/irqflags.h:102:
In file included from arch/x86/include/asm/paravirt.h:21:
In file included from include/linux/cpumask.h:12:
In file included from include/linux/bitmap.h:13:
In file included from include/linux/string.h:392:
>> include/linux/fortify-string.h:596:6: warning: non-constant static local variable in inline function may be different in different files [-Wstatic-local-in-inline]
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^
include/linux/compiler.h:47:24: note: expanded from macro 'unlikely'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^
include/linux/compiler.h:24:4: note: expanded from macro '__branch_check__'
24 | static struct ftrace_likely_data \
| ^
In file included from lib/tests/stackinit_kunit.c:14:
In file included from include/kunit/test.h:22:
In file included from include/linux/kref.h:16:
In file included from include/linux/spinlock.h:59:
In file included from include/linux/irqflags.h:18:
In file included from arch/x86/include/asm/irqflags.h:102:
In file included from arch/x86/include/asm/paravirt.h:21:
In file included from include/linux/cpumask.h:12:
In file included from include/linux/bitmap.h:13:
In file included from include/linux/string.h:392:
include/linux/fortify-string.h:598:11: warning: non-constant static local variable in inline function may be different in different files [-Wstatic-local-in-inline]
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^
include/linux/compiler.h:47:24: note: expanded from macro 'unlikely'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^
include/linux/compiler.h:24:4: note: expanded from macro '__branch_check__'
24 | static struct ftrace_likely_data \
| ^
lib/tests/stackinit_kunit.c:441:1: warning: initializer overrides prior initialization of this subobject [-Winitializer-overrides]
441 | DEFINE_UNION_INITIALIZER_TESTS(static, STRONG_PASS);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/tests/stackinit_kunit.c:421:3: note: expanded from macro 'DEFINE_UNION_INITIALIZER_TESTS'
421 | DEFINE_UNION_TESTS(base ## _ ## all, xfail)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/tests/stackinit_kunit.c:424:3: note: expanded from macro 'DEFINE_UNION_TESTS'
424 | DEFINE_UNION_TEST(same_sizes, init, xfail); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/tests/stackinit_kunit.c:403:3: note: expanded from macro 'DEFINE_UNION_TEST'
403 | DEFINE_TEST(name ## _ ## init, \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
404 | union test_ ## name, STRUCT, init, \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
405 | xfail)
| ~~~~~~
note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
<scratch space>:20:1: note: expanded from here
20 | INIT_STRUCT_static_all
| ^
lib/tests/stackinit_kunit.c:137:8: note: expanded from macro 'INIT_STRUCT_static_all'
137 | = __static_all
| ^~~~~~~~~~~~
lib/tests/stackinit_kunit.c:118:8: note: expanded from macro '__static_all'
118 | .two = 0, \
| ^~~~~~~~
lib/tests/stackinit_kunit.c:441:1: note: previous initialization is here
441 | DEFINE_UNION_INITIALIZER_TESTS(static, STRONG_PASS);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/tests/stackinit_kunit.c:421:3: note: expanded from macro 'DEFINE_UNION_INITIALIZER_TESTS'
421 | DEFINE_UNION_TESTS(base ## _ ## all, xfail)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/tests/stackinit_kunit.c:424:3: note: expanded from macro 'DEFINE_UNION_TESTS'
424 | DEFINE_UNION_TEST(same_sizes, init, xfail); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/tests/stackinit_kunit.c:403:3: note: expanded from macro 'DEFINE_UNION_TEST'
403 | DEFINE_TEST(name ## _ ## init, \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
404 | union test_ ## name, STRUCT, init, \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
405 | xfail)
| ~~~~~~
note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
<scratch space>:20:1: note: expanded from here
20 | INIT_STRUCT_static_all
| ^
lib/tests/stackinit_kunit.c:137:8: note: expanded from macro 'INIT_STRUCT_static_all'
137 | = __static_all
| ^~~~~~~~~~~~
lib/tests/stackinit_kunit.c:117:33: note: expanded from macro '__static_all'
117 | #define __static_all { .one = 0, \
| ^
lib/tests/stackinit_kunit.c:441:1: warning: initializer overrides prior initialization of this subobject [-Winitializer-overrides]
441 | DEFINE_UNION_INITIALIZER_TESTS(static, STRONG_PASS);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/tests/stackinit_kunit.c:421:3: note: expanded from macro 'DEFINE_UNION_INITIALIZER_TESTS'
421 | DEFINE_UNION_TESTS(base ## _ ## all, xfail)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/tests/stackinit_kunit.c:424:3: note: expanded from macro 'DEFINE_UNION_TESTS'
424 | DEFINE_UNION_TEST(same_sizes, init, xfail); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/tests/stackinit_kunit.c:403:3: note: expanded from macro 'DEFINE_UNION_TEST'
403 | DEFINE_TEST(name ## _ ## init, \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
404 | union test_ ## name, STRUCT, init, \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
405 | xfail)
| ~~~~~~
note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
<scratch space>:20:1: note: expanded from here
20 | INIT_STRUCT_static_all
| ^
lib/tests/stackinit_kunit.c:137:8: note: expanded from macro 'INIT_STRUCT_static_all'
..
vim +596 include/linux/fortify-string.h
515
516 /*
517 * To make sure the compiler can enforce protection against buffer overflows,
518 * memcpy(), memmove(), and memset() must not be used beyond individual
519 * struct members. If you need to copy across multiple members, please use
520 * struct_group() to create a named mirror of an anonymous struct union.
521 * (e.g. see struct sk_buff.) Read overflow checking is currently only
522 * done when a write overflow is also present, or when building with W=1.
523 *
524 * Mitigation coverage matrix
525 * Bounds checking at:
526 * +-------+-------+-------+-------+
527 * | Compile time | Run time |
528 * memcpy() argument sizes: | write | read | write | read |
529 * dest source length +-------+-------+-------+-------+
530 * memcpy(known, known, constant) | y | y | n/a | n/a |
531 * memcpy(known, unknown, constant) | y | n | n/a | V |
532 * memcpy(known, known, dynamic) | n | n | B | B |
533 * memcpy(known, unknown, dynamic) | n | n | B | V |
534 * memcpy(unknown, known, constant) | n | y | V | n/a |
535 * memcpy(unknown, unknown, constant) | n | n | V | V |
536 * memcpy(unknown, known, dynamic) | n | n | V | B |
537 * memcpy(unknown, unknown, dynamic) | n | n | V | V |
538 * +-------+-------+-------+-------+
539 *
540 * y = perform deterministic compile-time bounds checking
541 * n = cannot perform deterministic compile-time bounds checking
542 * n/a = no run-time bounds checking needed since compile-time deterministic
543 * B = can perform run-time bounds checking (currently unimplemented)
544 * V = vulnerable to run-time overflow (will need refactoring to solve)
545 *
546 */
547 __FORTIFY_INLINE bool fortify_memcpy_chk(__kernel_size_t size,
548 const size_t p_size,
549 const size_t q_size,
550 const size_t p_size_field,
551 const size_t q_size_field,
552 const u8 func)
553 {
554 if (__builtin_constant_p(size)) {
555 /*
556 * Length argument is a constant expression, so we
557 * can perform compile-time bounds checking where
558 * buffer sizes are also known at compile time.
559 */
560
561 /* Error when size is larger than enclosing struct. */
562 if (__compiletime_lessthan(p_size_field, p_size) &&
563 __compiletime_lessthan(p_size, size))
564 __write_overflow();
565 if (__compiletime_lessthan(q_size_field, q_size) &&
566 __compiletime_lessthan(q_size, size))
567 __read_overflow2();
568
569 /* Warn when write size argument larger than dest field. */
570 if (__compiletime_lessthan(p_size_field, size))
571 __write_overflow_field(p_size_field, size);
572 /*
573 * Warn for source field over-read when building with W=1
574 * or when an over-write happened, so both can be fixed at
575 * the same time.
576 */
577 if ((IS_ENABLED(KBUILD_EXTRA_WARN1) ||
578 __compiletime_lessthan(p_size_field, size)) &&
579 __compiletime_lessthan(q_size_field, size))
580 __read_overflow2_field(q_size_field, size);
581 }
582 /*
583 * At this point, length argument may not be a constant expression,
584 * so run-time bounds checking can be done where buffer sizes are
585 * known. (This is not an "else" because the above checks may only
586 * be compile-time warnings, and we want to still warn for run-time
587 * overflows.)
588 */
589
590 /*
591 * Always stop accesses beyond the struct that contains the
592 * field, when the buffer's remaining size is known.
593 * (The SIZE_MAX test is to optimize away checks where the buffer
594 * lengths are unknown.)
595 */
> 596 if (unlikely(p_size != SIZE_MAX && p_size < size))
597 fortify_panic(func, FORTIFY_WRITE, p_size, size, true);
598 else if (unlikely(q_size != SIZE_MAX && q_size < size))
599 fortify_panic(func, FORTIFY_READ, p_size, size, true);
600
601 /*
602 * Warn when writing beyond destination field size.
603 *
604 * Note the implementation of __builtin_*object_size() behaves
605 * like sizeof() when not directly referencing a flexible
606 * array member, which means there will be many bounds checks
607 * that will appear at run-time, without a way for them to be
608 * detected at compile-time (as can be done when the destination
609 * is specifically the flexible array member).
610 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101832
611 */
612 if (p_size_field != SIZE_MAX &&
613 p_size != p_size_field && p_size_field < size)
614 return true;
615
616 return false;
617 }
618
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH][next] fortify: add branch hints on unlikely fortify_panic paths
2025-06-25 16:12 [PATCH][next] fortify: add branch hints on unlikely fortify_panic paths Colin Ian King
2025-06-27 0:14 ` kernel test robot
@ 2025-06-27 1:05 ` kernel test robot
2025-06-27 16:36 ` Kees Cook
2 siblings, 0 replies; 5+ messages in thread
From: kernel test robot @ 2025-06-27 1:05 UTC (permalink / raw)
To: Colin Ian King, Kees Cook, linux-hardening
Cc: oe-kbuild-all, kernel-janitors, linux-kernel
Hi Colin,
kernel test robot noticed the following build warnings:
[auto build test WARNING on kees/for-next/hardening]
[also build test WARNING on kees/for-next/pstore kees/for-next/kspp linus/master v6.16-rc3 next-20250626]
[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/Colin-Ian-King/fortify-add-branch-hints-on-unlikely-fortify_panic-paths/20250626-001527
base: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/hardening
patch link: https://lore.kernel.org/r/20250625161221.295575-1-colin.i.king%40gmail.com
patch subject: [PATCH][next] fortify: add branch hints on unlikely fortify_panic paths
config: i386-buildonly-randconfig-004-20250627 (https://download.01.org/0day-ci/archive/20250627/202506270831.FzLx5USH-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250627/202506270831.FzLx5USH-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506270831.FzLx5USH-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from include/linux/array_size.h:5,
from include/linux/string.h:6,
from include/linux/uuid.h:11,
from include/linux/mod_devicetable.h:14,
from scripts/mod/devicetable-offsets.c:3:
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:598:18: note: in expansion of macro 'unlikely'
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^~~~~~~~
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:596:13: note: in expansion of macro 'unlikely'
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^~~~~~~~
--
In file included from include/linux/export.h:5,
from include/linux/linkage.h:7,
from arch/x86/include/asm/cache.h:5,
from include/vdso/cache.h:5,
from include/linux/cache.h:6,
from include/linux/slab.h:15,
from fs/ocfs2/dlmglue.c:11:
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:598:18: note: in expansion of macro 'unlikely'
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^~~~~~~~
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:596:13: note: in expansion of macro 'unlikely'
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^~~~~~~~
In file included from include/linux/string.h:392,
from arch/x86/include/asm/page_32.h:18,
from arch/x86/include/asm/page.h:14,
from arch/x86/include/asm/thread_info.h:12,
from include/linux/thread_info.h:60,
from include/linux/spinlock.h:60,
from include/linux/mmzone.h:8,
from include/linux/gfp.h:7,
from include/linux/slab.h:16:
In function 'fortify_memset_chk',
inlined from 'ocfs2_lock_res_free' at fs/ocfs2/dlmglue.c:791:2:
include/linux/fortify-string.h:480:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
480 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
kernel/bpf/helpers.c: In function '____bpf_snprintf':
kernel/bpf/helpers.c:1067:9: warning: function '____bpf_snprintf' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
1067 | err = bstr_printf(str, str_size, fmt, data.bin_args);
| ^~~
In file included from include/uapi/linux/filter.h:9,
from include/linux/bpf.h:8,
from kernel/bpf/helpers.c:4:
include/linux/fortify-string.h: At top level:
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:598:18: note: in expansion of macro 'unlikely'
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^~~~~~~~
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:596:13: note: in expansion of macro 'unlikely'
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^~~~~~~~
--
In file included from include/linux/build_bug.h:5,
from include/linux/bits.h:32,
from include/linux/ioport.h:13,
from include/linux/acpi.h:12,
from sound/soc/codecs/rt1318.c:10:
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:598:18: note: in expansion of macro 'unlikely'
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^~~~~~~~
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:596:13: note: in expansion of macro 'unlikely'
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^~~~~~~~
sound/soc/codecs/rt1318.c:1148:34: warning: 'rt1318_of_match' defined but not used [-Wunused-const-variable=]
1148 | static const struct of_device_id rt1318_of_match[] = {
| ^~~~~~~~~~~~~~~
--
In file included from include/linux/dev_printk.h:14,
from include/linux/device.h:15,
from include/linux/extcon.h:21,
from sound/soc/samsung/aries_wm8994.c:2:
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:598:18: note: in expansion of macro 'unlikely'
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^~~~~~~~
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:596:13: note: in expansion of macro 'unlikely'
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^~~~~~~~
sound/soc/samsung/aries_wm8994.c:524:34: warning: 'samsung_wm8994_of_match' defined but not used [-Wunused-const-variable=]
524 | static const struct of_device_id samsung_wm8994_of_match[] = {
| ^~~~~~~~~~~~~~~~~~~~~~~
--
kernel/trace/bpf_trace.c: In function '____bpf_trace_printk':
kernel/trace/bpf_trace.c:378:9: warning: function '____bpf_trace_printk' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
378 | ret = bstr_printf(data.buf, MAX_BPRINTF_BUF, fmt, data.bin_args);
| ^~~
kernel/trace/bpf_trace.c: In function '____bpf_trace_vprintk':
kernel/trace/bpf_trace.c:434:9: warning: function '____bpf_trace_vprintk' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
434 | ret = bstr_printf(data.buf, MAX_BPRINTF_BUF, fmt, data.bin_args);
| ^~~
kernel/trace/bpf_trace.c: In function '____bpf_seq_printf':
kernel/trace/bpf_trace.c:476:9: warning: function '____bpf_seq_printf' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
476 | seq_bprintf(m, fmt, data.bin_args);
| ^~~~~~~~~~~
In file included from include/linux/array_size.h:5,
from include/linux/kernel.h:16,
from kernel/trace/bpf_trace.c:5:
include/linux/fortify-string.h: At top level:
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:598:18: note: in expansion of macro 'unlikely'
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^~~~~~~~
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:596:13: note: in expansion of macro 'unlikely'
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^~~~~~~~
--
In file included from include/linux/err.h:5,
from drivers/regulator/pbias-regulator.c:17:
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:598:18: note: in expansion of macro 'unlikely'
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^~~~~~~~
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:596:13: note: in expansion of macro 'unlikely'
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^~~~~~~~
drivers/regulator/pbias-regulator.c:136:34: warning: 'pbias_of_match' defined but not used [-Wunused-const-variable=]
136 | static const struct of_device_id pbias_of_match[] = {
| ^~~~~~~~~~~~~~
--
drivers/iommu/mtk_iommu_v1.c: In function 'mtk_iommu_v1_probe_finalize':
drivers/iommu/mtk_iommu_v1.c:512:35: warning: variable 'mtk_mapping' set but not used [-Wunused-but-set-variable]
512 | struct dma_iommu_mapping *mtk_mapping;
| ^~~~~~~~~~~
In file included from include/asm-generic/bug.h:5,
from arch/x86/include/asm/bug.h:103,
from include/linux/bug.h:5,
from drivers/iommu/mtk_iommu_v1.c:10:
include/linux/fortify-string.h: At top level:
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:598:18: note: in expansion of macro 'unlikely'
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^~~~~~~~
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:596:13: note: in expansion of macro 'unlikely'
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^~~~~~~~
--
drivers/usb/renesas_usbhs/mod.c: In function 'usbhs_status_get_each_irq':
drivers/usb/renesas_usbhs/mod.c:195:13: warning: variable 'intenb0' set but not used [-Wunused-but-set-variable]
195 | u16 intenb0, intenb1;
| ^~~~~~~
In file included from include/linux/array_size.h:5,
from include/linux/kernel.h:16,
from include/linux/interrupt.h:6,
from drivers/usb/renesas_usbhs/mod.c:9:
include/linux/fortify-string.h: At top level:
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:598:18: note: in expansion of macro 'unlikely'
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^~~~~~~~
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:596:13: note: in expansion of macro 'unlikely'
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^~~~~~~~
--
fs/nfsd/export.c: In function 'exp_rootfh':
fs/nfsd/export.c:1029:34: warning: variable 'inode' set but not used [-Wunused-but-set-variable]
1029 | struct inode *inode;
| ^~~~~
In file included from include/linux/export.h:5,
from include/linux/linkage.h:7,
from arch/x86/include/asm/cache.h:5,
from include/vdso/cache.h:5,
from include/linux/cache.h:6,
from include/linux/slab.h:15,
from fs/nfsd/export.c:15:
include/linux/fortify-string.h: At top level:
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:598:18: note: in expansion of macro 'unlikely'
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^~~~~~~~
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:596:13: note: in expansion of macro 'unlikely'
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^~~~~~~~
--
In file included from include/linux/err.h:5,
from include/linux/clk.h:12,
from drivers/iio/adc/aspeed_adc.c:15:
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:598:18: note: in expansion of macro 'unlikely'
598 | else if (unlikely(q_size != SIZE_MAX && q_size < size))
| ^~~~~~~~
>> include/linux/compiler.h:27:33: warning: '______f' is static but declared in inline function 'fortify_memcpy_chk' which is not static
27 | ______f = { \
| ^~~~~~~
include/linux/compiler.h:47:26: note: in expansion of macro '__branch_check__'
47 | # define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
| ^~~~~~~~~~~~~~~~
include/linux/fortify-string.h:596:13: note: in expansion of macro 'unlikely'
596 | if (unlikely(p_size != SIZE_MAX && p_size < size))
| ^~~~~~~~
drivers/iio/adc/aspeed_adc.c: In function 'aspeed_adc_probe':
drivers/iio/adc/aspeed_adc.c:493:65: warning: '%s' directive argument is null [-Wformat-overflow=]
493 | snprintf(clk_parent_name, ARRAY_SIZE(clk_parent_name), "%s",
| ^~
..
vim +27 include/linux/compiler.h
1f0d69a9fc815d Steven Rostedt 2008-11-12 21
d45ae1f7041ac5 Steven Rostedt (VMware 2017-01-17 22) #define __branch_check__(x, expect, is_constant) ({ \
2026d35741f2c3 Mikulas Patocka 2018-05-30 23 long ______r; \
134e6a034cb004 Steven Rostedt (VMware 2017-01-19 24) static struct ftrace_likely_data \
e04462fb82f8dd Miguel Ojeda 2018-09-03 25 __aligned(4) \
33def8498fdde1 Joe Perches 2020-10-21 26 __section("_ftrace_annotated_branch") \
1f0d69a9fc815d Steven Rostedt 2008-11-12 @27 ______f = { \
134e6a034cb004 Steven Rostedt (VMware 2017-01-19 28) .data.func = __func__, \
134e6a034cb004 Steven Rostedt (VMware 2017-01-19 29) .data.file = __FILE__, \
134e6a034cb004 Steven Rostedt (VMware 2017-01-19 30) .data.line = __LINE__, \
1f0d69a9fc815d Steven Rostedt 2008-11-12 31 }; \
d45ae1f7041ac5 Steven Rostedt (VMware 2017-01-17 32) ______r = __builtin_expect(!!(x), expect); \
d45ae1f7041ac5 Steven Rostedt (VMware 2017-01-17 33) ftrace_likely_update(&______f, ______r, \
d45ae1f7041ac5 Steven Rostedt (VMware 2017-01-17 34) expect, is_constant); \
1f0d69a9fc815d Steven Rostedt 2008-11-12 35 ______r; \
1f0d69a9fc815d Steven Rostedt 2008-11-12 36 })
1f0d69a9fc815d Steven Rostedt 2008-11-12 37
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH][next] fortify: add branch hints on unlikely fortify_panic paths
2025-06-25 16:12 [PATCH][next] fortify: add branch hints on unlikely fortify_panic paths Colin Ian King
2025-06-27 0:14 ` kernel test robot
2025-06-27 1:05 ` kernel test robot
@ 2025-06-27 16:36 ` Kees Cook
2025-06-27 16:47 ` Colin King (gmail)
2 siblings, 1 reply; 5+ messages in thread
From: Kees Cook @ 2025-06-27 16:36 UTC (permalink / raw)
To: Colin Ian King; +Cc: linux-hardening, kernel-janitors, linux-kernel
On Wed, Jun 25, 2025 at 05:12:20PM +0100, Colin Ian King wrote:
> Analysis with gcov while running the stress-ng urandom stressor
> shows that there are a couple of fortify panic paths that are highly
> unlikely to be executed for well-behaving code. Adding appropriate
> branch hints improves the stress-ng urandom stressor my a small
> but statistically measureable amount. Ran 100 x 1 minute tests and
> measured the stressor bogo-op rates on a Debian based Intel(R)
> Core(TM) Ultra 9 285K with a 6.15 kernel with turbo disabled to
> reduce jitter.
>
> Results based on a Geometic Mean of 100 tests:
>
> Without patch: 50512.95 bogo-ops/sec
> With patch: 50819.58 bogo-ops/sec
>
> %Std.Deviation of ~0.18%, so low jitter in results, improvement of ~0.6%
>
> Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Nice find! It seems some ftrace configs are unhappy with this change,
though?
-Kees
--
Kees Cook
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH][next] fortify: add branch hints on unlikely fortify_panic paths
2025-06-27 16:36 ` Kees Cook
@ 2025-06-27 16:47 ` Colin King (gmail)
0 siblings, 0 replies; 5+ messages in thread
From: Colin King (gmail) @ 2025-06-27 16:47 UTC (permalink / raw)
To: Kees Cook; +Cc: linux-hardening, kernel-janitors, linux-kernel
[-- Attachment #1.1.1: Type: text/plain, Size: 1099 bytes --]
On 27/06/2025 17:36, Kees Cook wrote:
> On Wed, Jun 25, 2025 at 05:12:20PM +0100, Colin Ian King wrote:
>> Analysis with gcov while running the stress-ng urandom stressor
>> shows that there are a couple of fortify panic paths that are highly
>> unlikely to be executed for well-behaving code. Adding appropriate
>> branch hints improves the stress-ng urandom stressor my a small
>> but statistically measureable amount. Ran 100 x 1 minute tests and
>> measured the stressor bogo-op rates on a Debian based Intel(R)
>> Core(TM) Ultra 9 285K with a 6.15 kernel with turbo disabled to
>> reduce jitter.
>>
>> Results based on a Geometic Mean of 100 tests:
>>
>> Without patch: 50512.95 bogo-ops/sec
>> With patch: 50819.58 bogo-ops/sec
>>
>> %Std.Deviation of ~0.18%, so low jitter in results, improvement of ~0.6%
>>
>> Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
>
> Nice find! It seems some ftrace configs are unhappy with this change,
> though?
I'll resend once I get some time to figure out the issues with the
ftrace configs
Colin
>
> -Kees
>
[-- Attachment #1.1.2: OpenPGP public key --]
[-- Type: application/pgp-keys, Size: 4901 bytes --]
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 840 bytes --]
^ permalink raw reply [flat|nested] 5+ messages in thread