Messages in this thread | | | Date | Mon, 13 Mar 2023 11:24:28 +0800 | Subject | Re: [PATCH] LoongArch: Add support for function error injection | From | Hengqi Chen <> |
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On 2023/3/10 10:07, Tiezhu Yang wrote: > This feature is related with kprobes, add Masami to CC. > > On 03/07/2023 03:10 PM, Tiezhu Yang wrote: >> Inspired by the commit 42d038c4fb00 ("arm64: Add support for function error >> injection") and commit ee55ff803b38 ("riscv: Add support for function error >> injection"), support function error injection for LoongArch. >> >> Mainly implement two functions: >> (1) regs_set_return_value() which is used to overwrite the return value, >> (2) override_function_with_return() which is used to override the probed >> function returning and jump to its caller. >> >> Here is a simple test under CONFIG_FUNCTION_ERROR_INJECTION and >> CONFIG_FAIL_FUNCTION: >> >> # echo sys_clone > /sys/kernel/debug/fail_function/inject >> # echo 100 > /sys/kernel/debug/fail_function/probability >> # dmesg >> bash: fork: Invalid argument >> # dmesg >> ... >> FAULT_INJECTION: forcing a failure. >> name fail_function, interval 1, probability 100, space 0, times 1 >> ... >> Call Trace: >> [<90000000002238f4>] show_stack+0x5c/0x180 >> [<90000000012e384c>] dump_stack_lvl+0x60/0x88 >> [<9000000000b1879c>] should_fail_ex+0x1b0/0x1f4 >> [<900000000032ead4>] fei_kprobe_handler+0x28/0x6c >> [<9000000000230970>] kprobe_breakpoint_handler+0xf0/0x118 >> [<90000000012e3e60>] do_bp+0x2c4/0x358 >> [<9000000002241924>] exception_handlers+0x1924/0x10000 >> [<900000000023b7d0>] sys_clone+0x0/0x4 >> [<90000000012e4744>] do_syscall+0x7c/0x94 >> [<9000000000221e44>] handle_syscall+0xc4/0x160 >> >> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> >> --- >> arch/loongarch/Kconfig | 1 + >> arch/loongarch/include/asm/ptrace.h | 6 ++++++ >> arch/loongarch/lib/Makefile | 2 ++ >> arch/loongarch/lib/error-inject.c | 10 ++++++++++ >> 4 files changed, 19 insertions(+) >> create mode 100644 arch/loongarch/lib/error-inject.c >> >> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig >> index 7fd5125..b16ff7e 100644 >> --- a/arch/loongarch/Kconfig >> +++ b/arch/loongarch/Kconfig >> @@ -99,6 +99,7 @@ config LOONGARCH >> select HAVE_FAST_GUP >> select HAVE_FTRACE_MCOUNT_RECORD >> select HAVE_FUNCTION_ARG_ACCESS_API >> + select HAVE_FUNCTION_ERROR_INJECTION >> select HAVE_FUNCTION_GRAPH_TRACER >> select HAVE_FUNCTION_TRACER >> select HAVE_GENERIC_VDSO >> diff --git a/arch/loongarch/include/asm/ptrace.h b/arch/loongarch/include/asm/ptrace.h >> index d761db9..db7332a 100644 >> --- a/arch/loongarch/include/asm/ptrace.h >> +++ b/arch/loongarch/include/asm/ptrace.h >> @@ -154,6 +154,12 @@ static inline long regs_return_value(struct pt_regs *regs) >> return regs->regs[4]; >> } >> >> +static inline void regs_set_return_value(struct pt_regs *regs, >> + unsigned long val) >> +{ >> + regs->regs[4] = val; >> +} >> + >> #define instruction_pointer(regs) ((regs)->csr_era) >> #define profile_pc(regs) instruction_pointer(regs) >> >> diff --git a/arch/loongarch/lib/Makefile b/arch/loongarch/lib/Makefile >> index 40bde63..30b1595 100644 >> --- a/arch/loongarch/lib/Makefile >> +++ b/arch/loongarch/lib/Makefile >> @@ -5,3 +5,5 @@ >> >> lib-y += delay.o memset.o memcpy.o memmove.o \ >> clear_user.o copy_user.o dump_tlb.o unaligned.o >> + >> +obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o >> diff --git a/arch/loongarch/lib/error-inject.c b/arch/loongarch/lib/error-inject.c >> new file mode 100644 >> index 0000000..afc9e1c >> --- /dev/null >> +++ b/arch/loongarch/lib/error-inject.c >> @@ -0,0 +1,10 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> + >> +#include <linux/error-injection.h> >> +#include <linux/kprobes.h> >> + >> +void override_function_with_return(struct pt_regs *regs) >> +{ >> + instruction_pointer_set(regs, regs->regs[1]); >> +} >> +NOKPROBE_SYMBOL(override_function_with_return); >> > >
Tested-by: Hengqi Chen <hengqi.chen@gmail.com>
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