From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- arch/sh/Makefile | 193 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 193 insertions(+) create mode 100644 arch/sh/Makefile (limited to 'arch/sh/Makefile') diff --git a/arch/sh/Makefile b/arch/sh/Makefile new file mode 100644 index 000000000..7b420424b --- /dev/null +++ b/arch/sh/Makefile @@ -0,0 +1,193 @@ +# +# arch/sh/Makefile +# +# Copyright (C) 1999 Kaz Kojima +# Copyright (C) 2002 - 2008 Paul Mundt +# Copyright (C) 2002 M. R. Brown +# +# This file is subject to the terms and conditions of the GNU General Public +# License. See the file "COPYING" in the main directory of this archive +# for more details. +# +ifdef cross_compiling + ifeq ($(CROSS_COMPILE),) + CROSS_COMPILE := $(call cc-cross-prefix, sh-linux- sh-linux-gnu- sh-unknown-linux-gnu-) + endif +endif + +KBUILD_DEFCONFIG := shx3_defconfig + +isa-y := any +isa-$(CONFIG_SH_DSP) := sh +isa-$(CONFIG_CPU_SH2) := sh2 +isa-$(CONFIG_CPU_SH2A) := sh2a +isa-$(CONFIG_CPU_SH3) := sh3 +isa-$(CONFIG_CPU_SH4) := sh4 +isa-$(CONFIG_CPU_SH4A) := sh4a +isa-$(CONFIG_CPU_SH4AL_DSP) := sh4al + +isa-$(CONFIG_SH_DSP) := $(isa-y)-dsp +isa-y := $(isa-y)-up + +cflags-$(CONFIG_CPU_SH2) := $(call cc-option,-m2,) +cflags-$(CONFIG_CPU_J2) += $(call cc-option,-mj2,) +cflags-$(CONFIG_CPU_SH2A) += $(call cc-option,-m2a,) \ + $(call cc-option,-m2a-nofpu,) \ + $(call cc-option,-m4-nofpu,) +cflags-$(CONFIG_CPU_SH3) := $(call cc-option,-m3,) +cflags-$(CONFIG_CPU_SH4) := $(call cc-option,-m4,) \ + $(call cc-option,-mno-implicit-fp,-m4-nofpu) +cflags-$(CONFIG_CPU_SH4A) += $(call cc-option,-m4a,) \ + $(call cc-option,-m4a-nofpu,) +cflags-$(CONFIG_CPU_SH4AL_DSP) += $(call cc-option,-m4al,) + +ifeq ($(cflags-y),) +# +# In the case where we are stuck with a compiler that has been uselessly +# restricted to a particular ISA, a favourite default of newer GCCs when +# extensive multilib targets are not provided, ensure we get the best fit +# regarding FP generation. This is intentionally stupid (albeit many +# orders of magnitude less than GCC's default behaviour), as anything +# with a large number of multilib targets better have been built +# correctly for the target in mind. +# +cflags-y += $(shell $(CC) $(KBUILD_CFLAGS) -print-multi-lib | \ + grep nofpu | sed q | sed -e 's/^/-/;s/;.*$$//') +# At this point, anything goes. +isaflags-y := $(call as-option,-Wa$(comma)-isa=any,) +else +# +# -Wa,-isa= tuning implies -Wa,-dsp for the versions of binutils that +# support it, while -Wa,-dsp by itself limits the range of usable opcodes +# on certain CPU subtypes. Try the ISA variant first, and if that fails, +# fall back on -Wa,-dsp for the old binutils versions. Even without DSP +# opcodes, we always want the best ISA tuning the version of binutils +# will provide. +# +isaflags-y := $(call as-option,-Wa$(comma)-isa=$(isa-y),) + +isaflags-$(CONFIG_SH_DSP) := \ + $(call as-option,-Wa$(comma)-isa=$(isa-y),-Wa$(comma)-dsp) +endif + +cflags-$(CONFIG_CPU_BIG_ENDIAN) += -mb +cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -ml + +cflags-y += $(call cc-option,-mno-fdpic) +cflags-y += $(isaflags-y) -ffreestanding + +OBJCOPYFLAGS := -O binary -R .note -R .note.gnu.build-id -R .comment \ + -R .stab -R .stabstr -S + +# Give the various platforms the opportunity to set default image types +defaultimage-y := zImage +defaultimage-$(CONFIG_SH_SH7785LCR) := uImage +defaultimage-$(CONFIG_SH_RSK) := uImage +defaultimage-$(CONFIG_SH_URQUELL) := uImage +defaultimage-$(CONFIG_SH_MIGOR) := uImage +defaultimage-$(CONFIG_SH_AP325RXA) := uImage +defaultimage-$(CONFIG_SH_SH7757LCR) := uImage +defaultimage-$(CONFIG_SH_7724_SOLUTION_ENGINE) := uImage +defaultimage-$(CONFIG_SH_7206_SOLUTION_ENGINE) := vmlinux +defaultimage-$(CONFIG_SH_7619_SOLUTION_ENGINE) := vmlinux + +# Set some sensible Kbuild defaults +boot := arch/sh/boot +KBUILD_IMAGE := $(boot)/$(defaultimage-y) + +# +# Choosing incompatible machines durings configuration will result in +# error messages during linking. +# +UTS_MACHINE := sh +LDFLAGS_vmlinux += -e _stext + +ifdef CONFIG_CPU_LITTLE_ENDIAN +ld_bfd := elf32-sh-linux +LDFLAGS_vmlinux += --defsym jiffies=jiffies_64 --oformat $(ld_bfd) +KBUILD_LDFLAGS += -EL +else +ld_bfd := elf32-shbig-linux +LDFLAGS_vmlinux += --defsym jiffies=jiffies_64+4 --oformat $(ld_bfd) +KBUILD_LDFLAGS += -EB +endif + +export ld_bfd + +# Mach groups +machdir-$(CONFIG_SOLUTION_ENGINE) += mach-se +machdir-$(CONFIG_SH_DREAMCAST) += mach-dreamcast +machdir-$(CONFIG_SH_SH03) += mach-sh03 +machdir-$(CONFIG_SH_MIGOR) += mach-migor +machdir-$(CONFIG_SH_KFR2R09) += mach-kfr2r09 +machdir-$(CONFIG_SH_ECOVEC) += mach-ecovec24 +machdir-$(CONFIG_SH_SDK7786) += mach-sdk7786 +machdir-$(CONFIG_SH_X3PROTO) += mach-x3proto +machdir-$(CONFIG_SH_LANDISK) += mach-landisk +machdir-y += mach-common + +# +# CPU header paths +# +# These are ordered by optimization level. A CPU family that is a subset +# of another (ie, SH-2A / SH-2), is picked up first, with increasing +# levels of genericness if nothing more suitable is situated in the +# hierarchy. +# +# As an example, in order of preference, SH-2A > SH-2 > common definitions. +# +cpuincdir-$(CONFIG_CPU_SH2A) += cpu-sh2a +cpuincdir-$(CONFIG_CPU_SH2) += cpu-sh2 +cpuincdir-$(CONFIG_CPU_SH3) += cpu-sh3 +cpuincdir-$(CONFIG_CPU_SH4A) += cpu-sh4a +cpuincdir-$(CONFIG_CPU_SH4) += cpu-sh4 +cpuincdir-y += cpu-common # Must be last + +drivers-y += arch/sh/drivers/ + +KBUILD_CPPFLAGS += $(addprefix -I $(srctree)/arch/sh/include/, $(cpuincdir-y) $(machdir-y)) +KBUILD_CFLAGS += -pipe $(cflags-y) +KBUILD_AFLAGS += $(cflags-y) + +ifeq ($(CONFIG_MCOUNT),y) + KBUILD_CFLAGS += -pg +endif + +ifeq ($(CONFIG_DWARF_UNWINDER),y) + KBUILD_CFLAGS += -fasynchronous-unwind-tables +endif + +libs-y := arch/sh/lib/ $(libs-y) + +BOOT_TARGETS = uImage uImage.bz2 uImage.gz uImage.lzma uImage.xz uImage.lzo \ + uImage.srec uImage.bin zImage vmlinux.bin vmlinux.srec \ + romImage +PHONY += $(BOOT_TARGETS) + +all: $(notdir $(KBUILD_IMAGE)) + +$(BOOT_TARGETS): vmlinux + $(Q)$(MAKE) $(build)=$(boot) $(boot)/$@ + +compressed: zImage + +archprepare: + $(Q)$(MAKE) $(build)=arch/sh/tools include/generated/machtypes.h + +archheaders: + $(Q)$(MAKE) $(build)=arch/sh/kernel/syscalls all + +define archhelp + @echo ' zImage - Compressed kernel image' + @echo ' romImage - Compressed ROM image, if supported' + @echo ' vmlinux.srec - Create an ELF S-record' + @echo ' vmlinux.bin - Create an uncompressed binary image' + @echo '* uImage - Alias to bootable U-Boot image' + @echo ' uImage.srec - Create an S-record for U-Boot' + @echo ' uImage.bin - Kernel-only image for U-Boot (bin)' + @echo '* uImage.gz - Kernel-only image for U-Boot (gzip)' + @echo ' uImage.bz2 - Kernel-only image for U-Boot (bzip2)' + @echo ' uImage.lzma - Kernel-only image for U-Boot (lzma)' + @echo ' uImage.xz - Kernel-only image for U-Boot (xz)' + @echo ' uImage.lzo - Kernel-only image for U-Boot (lzo)' +endef -- cgit v1.3.1