From: Rui Qi Date: Tue, 21 Jul 2026 15:05:09 +0000 (+0800) Subject: riscv: hwprobe: Register unaligned probes before usermode X-Git-Tag: v7.2~23^2~1 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=994dad686e755477e2b2700cca4e6e1a90a58bdc;p=thirdparty%2Fkernel%2Flinux.git riscv: hwprobe: Register unaligned probes before usermode The hwprobe vDSO data is populated by the first riscv_hwprobe syscall. Some values, such as MISALIGNED_VECTOR_PERF, may depend on the async vector unaligned access speed probe registered by check_unaligned_access_all_cpus(). That initcall currently runs at late_initcall level. However, rootfs_initcall enables usermode helpers before late initcalls run, so an early helper can execute userspace and call riscv_hwprobe first. In that case complete_hwprobe_vdso_data() consumes the initial pending_boot_probes reference, populates the vDSO cache, and marks it ready before the later async probe is registered. The eventual probe result then cannot update the already-ready cache. Move check_unaligned_access_all_cpus() to fs_initcall_sync. This still runs after clocksource_done_booting(), so the ktime_get_mono_fast_ns() benchmark uses a stable clocksource, but it runs before rootfs_initcall enables usermode helpers. Any async hwprobe probe is therefore registered before userspace can trigger the one-time vDSO cache population. Cc: stable@vger.kernel.org Fixes: 6455c6c11827 ("riscv: Clean up & optimize unaligned scalar access probe") Signed-off-by: Rui Qi Reviewed-by: Nam Cao Link: https://patch.msgid.link/20260721150511.1607105-1-qirui.001@bytedance.com Signed-off-by: Paul Walmsley --- diff --git a/arch/riscv/kernel/unaligned_access_speed.c b/arch/riscv/kernel/unaligned_access_speed.c index 5a5aa22124e7..36201613d2ca 100644 --- a/arch/riscv/kernel/unaligned_access_speed.c +++ b/arch/riscv/kernel/unaligned_access_speed.c @@ -411,4 +411,10 @@ static int __init check_unaligned_access_all_cpus(void) return 0; } -late_initcall(check_unaligned_access_all_cpus); +/* + * Run after clocksource_done_booting() so measure_cycles() uses a stable + * clocksource, but before rootfs_initcall() enables usermode helpers. Those + * helpers can reach hwprobe and populate the vDSO cache, so async hwprobe + * probes must be registered first. + */ +fs_initcall_sync(check_unaligned_access_all_cpus);