From 251b5497c5c95e4548e3d33cbda3f638fea2c11e Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Sat, 23 Jan 2021 21:01:48 -0800 Subject: ubsan: disable unsigned-overflow check for i386 Building ubsan kernels even for compile-testing introduced these warnings in my randconfig environment: crypto/blake2b_generic.c:98:13: error: stack frame size of 9636 bytes in function 'blake2b_compress' [-Werror,-Wframe-larger-than=] static void blake2b_compress(struct blake2b_state *S, crypto/sha512_generic.c:151:13: error: stack frame size of 1292 bytes in function 'sha512_generic_block_fn' [-Werror,-Wframe-larger-than=] static void sha512_generic_block_fn(struct sha512_state *sst, u8 const *src, lib/crypto/curve25519-fiat32.c:312:22: error: stack frame size of 2180 bytes in function 'fe_mul_impl' [-Werror,-Wframe-larger-than=] static noinline void fe_mul_impl(u32 out[10], const u32 in1[10], const u32 in2[10]) lib/crypto/curve25519-fiat32.c:444:22: error: stack frame size of 1588 bytes in function 'fe_sqr_impl' [-Werror,-Wframe-larger-than=] static noinline void fe_sqr_impl(u32 out[10], const u32 in1[10]) Further testing showed that this is caused by -fsanitize=unsigned-integer-overflow, but is isolated to the 32-bit x86 architecture. The one in blake2b immediately overflows the 8KB stack area architectures, so better ensure this never happens by disabling the option for 32-bit x86. Link: https://lkml.kernel.org/r/20210112202922.2454435-1-arnd@kernel.org Link: https://lore.kernel.org/lkml/20201230154749.746641-1-arnd@kernel.org/ Fixes: d0a3ac549f38 ("ubsan: enable for all*config builds") Signed-off-by: Arnd Bergmann Acked-by: Kees Cook Reviewed-by: Nathan Chancellor Cc: Nick Desaulniers Cc: Stephen Rothwell Cc: Marco Elver Cc: George Popescu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/Kconfig.ubsan | 1 + 1 file changed, 1 insertion(+) (limited to 'lib') diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan index 8b635fd75fe4..3a0b1c930733 100644 --- a/lib/Kconfig.ubsan +++ b/lib/Kconfig.ubsan @@ -123,6 +123,7 @@ config UBSAN_SIGNED_OVERFLOW config UBSAN_UNSIGNED_OVERFLOW bool "Perform checking for unsigned arithmetic overflow" depends on $(cc-option,-fsanitize=unsigned-integer-overflow) + depends on !X86_32 # avoid excessive stack usage on x86-32/clang help This option enables -fsanitize=unsigned-integer-overflow which checks for overflow of any arithmetic operations with unsigned integers. This -- cgit v1.2.3 From 28abcc963149e06d956d95a18a85f4ba26af746f Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Thu, 4 Feb 2021 18:32:57 -0800 Subject: ubsan: implement __ubsan_handle_alignment_assumption When building ARCH=mips 32r2el_defconfig with CONFIG_UBSAN_ALIGNMENT: ld.lld: error: undefined symbol: __ubsan_handle_alignment_assumption referenced by slab.h:557 (include/linux/slab.h:557) main.o:(do_initcalls) in archive init/built-in.a referenced by slab.h:448 (include/linux/slab.h:448) do_mounts_rd.o:(rd_load_image) in archive init/built-in.a referenced by slab.h:448 (include/linux/slab.h:448) do_mounts_rd.o:(identify_ramdisk_image) in archive init/built-in.a referenced 1579 more times Implement this for the kernel based on LLVM's handleAlignmentAssumptionImpl because the kernel is not linked against the compiler runtime. Link: https://github.com/ClangBuiltLinux/linux/issues/1245 Link: https://github.com/llvm/llvm-project/blob/llvmorg-11.0.1/compiler-rt/lib/ubsan/ubsan_handlers.cpp#L151-L190 Link: https://lkml.kernel.org/r/20210127224451.2587372-1-nathan@kernel.org Signed-off-by: Nathan Chancellor Acked-by: Kees Cook Reviewed-by: Nick Desaulniers Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/ubsan.c | 31 +++++++++++++++++++++++++++++++ lib/ubsan.h | 6 ++++++ 2 files changed, 37 insertions(+) (limited to 'lib') diff --git a/lib/ubsan.c b/lib/ubsan.c index 3e3352f3d0da..bec38c64d6a6 100644 --- a/lib/ubsan.c +++ b/lib/ubsan.c @@ -427,3 +427,34 @@ void __ubsan_handle_load_invalid_value(void *_data, void *val) ubsan_epilogue(); } EXPORT_SYMBOL(__ubsan_handle_load_invalid_value); + +void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr, + unsigned long align, + unsigned long offset); +void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr, + unsigned long align, + unsigned long offset) +{ + struct alignment_assumption_data *data = _data; + unsigned long real_ptr; + + if (suppress_report(&data->location)) + return; + + ubsan_prologue(&data->location, "alignment-assumption"); + + if (offset) + pr_err("assumption of %lu byte alignment (with offset of %lu byte) for pointer of type %s failed", + align, offset, data->type->type_name); + else + pr_err("assumption of %lu byte alignment for pointer of type %s failed", + align, data->type->type_name); + + real_ptr = ptr - offset; + pr_err("%saddress is %lu aligned, misalignment offset is %lu bytes", + offset ? "offset " : "", BIT(real_ptr ? __ffs(real_ptr) : 0), + real_ptr & (align - 1)); + + ubsan_epilogue(); +} +EXPORT_SYMBOL(__ubsan_handle_alignment_assumption); diff --git a/lib/ubsan.h b/lib/ubsan.h index 7b56c09473a9..9a0b71c5ff9f 100644 --- a/lib/ubsan.h +++ b/lib/ubsan.h @@ -78,6 +78,12 @@ struct invalid_value_data { struct type_descriptor *type; }; +struct alignment_assumption_data { + struct source_location location; + struct source_location assumption_location; + struct type_descriptor *type; +}; + #if defined(CONFIG_ARCH_SUPPORTS_INT128) typedef __int128 s_max; typedef unsigned __int128 u_max; -- cgit v1.2.3 From 2452483d9546de1c540f330469dc4042ff089731 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 5 Feb 2021 23:28:29 +0100 Subject: Revert "lib: Restrict cpumask_local_spread to houskeeping CPUs" This reverts commit 1abdfe706a579a702799fce465bceb9fb01d407c. This change is broken and not solving any problem it claims to solve. Robin reported that cpumask_local_spread() now returns any cpu out of cpu_possible_mask in case that NOHZ_FULL is disabled (runtime or compile time). It can also return any offline or not-present CPU in the housekeeping mask. Before that it was returning a CPU out of online_cpu_mask. While the function is racy against CPU hotplug if the caller does not protect against it, the actual use cases are not caring much about it as they use it mostly as hint for: - the user space affinity hint which is unused by the kernel - memory node selection which is just suboptimal - network queue affinity which might fail but is handled gracefully But the occasional fail vs. hotplug is very different from returning anything from possible_cpu_mask which can have a large amount of offline CPUs obviously. The changelog of the commit claims: "The current implementation of cpumask_local_spread() does not respect the isolated CPUs, i.e., even if a CPU has been isolated for Real-Time task, it will return it to the caller for pinning of its IRQ threads. Having these unwanted IRQ threads on an isolated CPU adds up to a latency overhead." The only correct part of this changelog is: "The current implementation of cpumask_local_spread() does not respect the isolated CPUs." Everything else is just disjunct from reality. Reported-by: Robin Murphy Signed-off-by: Thomas Gleixner Cc: Nitesh Narayan Lal Cc: Marcelo Tosatti Cc: abelits@marvell.com Cc: davem@davemloft.net Link: https://lore.kernel.org/r/87y2g26tnt.fsf@nanos.tec.linutronix.de --- lib/cpumask.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) (limited to 'lib') diff --git a/lib/cpumask.c b/lib/cpumask.c index 35924025097b..c3c76b833384 100644 --- a/lib/cpumask.c +++ b/lib/cpumask.c @@ -6,7 +6,6 @@ #include #include #include -#include /** * cpumask_next - get the next cpu in a cpumask @@ -206,27 +205,22 @@ void __init free_bootmem_cpumask_var(cpumask_var_t mask) */ unsigned int cpumask_local_spread(unsigned int i, int node) { - int cpu, hk_flags; - const struct cpumask *mask; + int cpu; - hk_flags = HK_FLAG_DOMAIN | HK_FLAG_MANAGED_IRQ; - mask = housekeeping_cpumask(hk_flags); /* Wrap: we always want a cpu. */ - i %= cpumask_weight(mask); + i %= num_online_cpus(); if (node == NUMA_NO_NODE) { - for_each_cpu(cpu, mask) { + for_each_cpu(cpu, cpu_online_mask) if (i-- == 0) return cpu; - } } else { /* NUMA first. */ - for_each_cpu_and(cpu, cpumask_of_node(node), mask) { + for_each_cpu_and(cpu, cpumask_of_node(node), cpu_online_mask) if (i-- == 0) return cpu; - } - for_each_cpu(cpu, mask) { + for_each_cpu(cpu, cpu_online_mask) { /* Skip NUMA nodes, done above. */ if (cpumask_test_cpu(cpu, cpumask_of_node(node))) continue; -- cgit v1.2.3