arm64: Fix KASAN random tag seed initialization

Currently, kasan_init_sw_tags() is called before setup_per_cpu_areas(),
so per_cpu(prng_state, cpu) accesses the same address regardless of the
value of "cpu", and the same seed value gets copied to the percpu area
for every CPU. Fix this by moving the call to smp_prepare_boot_cpu(),
which is the first architecture hook after setup_per_cpu_areas().

Fixes: 3c9e3aa11094 ("kasan: add tag related helper functions")
Fixes: 3f41b6093823 ("kasan: fix random seed generation for tag-based mode")
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Link: https://lore.kernel.org/r/20240814091005.969756-1-samuel.holland@sifive.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index a096e2451044d35bad506ecb67edcf3f2d30b87c..b22d28ec80284b1c4f593a4ffc51ed2b7012f7a3 100644 (file)
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -355,9 +355,6 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)
        smp_init_cpus();
        smp_build_mpidr_hash();
 
-       /* Init percpu seeds for random tags after cpus are set up. */
-       kasan_init_sw_tags();
-
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
        /*
         * Make sure init_thread_info.ttbr0 always generates translation

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 5e18fbcee9a20cb3605b1421b32343613fde0dfd..f01f0fd7b7feb4a98c09d9184a703f5e76a89ce6 100644 (file)
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -467,6 +467,8 @@ void __init smp_prepare_boot_cpu(void)
                init_gic_priority_masking();
 
        kasan_init_hw_tags();
+       /* Init percpu seeds for random tags after cpus are set up. */
+       kasan_init_sw_tags();
 }
 
 /*