Messages in this thread | | | Subject | Re: [PATCH] LoongArch: Add support for function error injection | From | Tiezhu Yang <> | Date | Fri, 10 Mar 2023 10:07:09 +0800 |
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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); >
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