This is a note to let you know that I've just added the patch titled
arm64: Fix KASAN random tag seed initialization
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm64-fix-kasan-random-tag-seed-initialization.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit cf9afa4953d69e24006e29072d9c4116ca9cc9db
Author: Samuel Holland <samuel.holland@xxxxxxxxxx>
Date: Wed Aug 14 02:09:53 2024 -0700
arm64: Fix KASAN random tag seed initialization
[ Upstream commit f75c235565f90c4a17b125e47f1c68ef6b8c2bce ]
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@xxxxxxxxxx>
Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Link: https://lore.kernel.org/r/20240814091005.969756-1-samuel.holland@xxxxxxxxxx
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index be5f85b0a24de..6a9028bfd0434 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -364,9 +364,6 @@ 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 bc29cc044a4d7..47684a03c42f8 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -464,6 +464,8 @@ 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();
}
static u64 __init of_get_cpu_mpidr(struct device_node *dn)
