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charset="utf-8" With gcc-15 and gcc-16 with UBSAN_ALIGNMENT enabled the compiler fails to inline and optimize __scoped_seqlock_bug() away on s390: s390x-16.1.0-ld: kernel/sched/build_policy.o: in function `__scoped_seqlock= _next': /.../seqlock.h:1286:(.text+0x22030): undefined reference to `__scoped_seqlo= ck_bug' Fix this by adding UBSAN_ALIGNMENT to the list of config options where a not inlined empty __scoped_seqlock_bug() is allowed. Reported-by: Arnd Bergmann Closes: https://lore.kernel.org/r/20260515092057.810542-1-arnd@kernel.org/ Signed-off-by: Heiko Carstens Tested-by: Arnd Bergmann --- include/linux/seqlock.h | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h index 5a40252b8334..f865491c4f2c 100644 --- a/include/linux/seqlock.h +++ b/include/linux/seqlock.h @@ -1259,14 +1259,15 @@ static __always_inline void __scoped_seqlock_cleanu= p(struct ss_tmp *sst) =20 extern void __scoped_seqlock_invalid_target(void); =20 -#if (defined(CONFIG_CC_IS_GCC) && CONFIG_GCC_VERSION < 90000) || defined(C= ONFIG_KASAN) +#if (defined(CONFIG_CC_IS_GCC) && CONFIG_GCC_VERSION < 90000) || \ + defined(CONFIG_KASAN) || defined(CONFIG_UBSAN_ALIGNMENT) /* * For some reason some GCC-8 architectures (nios2, alpha) have trouble * determining that the ss_done state is impossible in __scoped_seqlock_ne= xt() * below. * - * Similarly KASAN is known to confuse compilers enough to break this. But= we - * don't care about code quality for KASAN builds anyway. + * Similarly KASAN and UBSAN_ALIGNMENT are known to confuse compilers enou= gh + * to break this. But we don't care about code quality for such builds any= way. */ static inline void __scoped_seqlock_bug(void) { } #else --=20 2.51.0