Messages in this thread | | | Date | Mon, 9 Oct 2023 10:43:10 -0700 | From | Charlie Jenkins <> | Subject | Re: [PATCH] riscv: blacklist assembly symbols for kprobe |
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On Wed, Oct 04, 2023 at 03:10:09PM +0200, Clément Léger wrote: > Adding kprobes on some assembly functions (mainly exception handling) > will result in crashes (either recursive trap or panic). To avoid such > errors, add ASM_NOKPROBE() macro which allow adding specific symbols > into the __kprobe_blacklist section and use to blacklist the following > symbols that showed to be problematic: > - handle_exception() > - ret_from_exception() > - handle_kernel_stack_overflow() > > Signed-off-by: Clément Léger <cleger@rivosinc.com> > --- > arch/riscv/include/asm/asm.h | 10 ++++++++++ > arch/riscv/kernel/entry.S | 3 +++ > 2 files changed, 13 insertions(+) > > diff --git a/arch/riscv/include/asm/asm.h b/arch/riscv/include/asm/asm.h > index 114bbadaef41..9194e334de15 100644 > --- a/arch/riscv/include/asm/asm.h > +++ b/arch/riscv/include/asm/asm.h > @@ -142,6 +142,16 @@ > REG_L x31, PT_T6(sp) > .endm > > +/* Annotate a function as being unsuitable for kprobes. */ > +#ifdef CONFIG_KPROBES > +#define ASM_NOKPROBE(name) \ > + .pushsection "_kprobe_blacklist", "aw"; \ > + RISCV_PTR name; \ > + .popsection > +#else > +#define ASM_NOKPROBE(name) > +#endif > + > #endif /* __ASSEMBLY__ */ > > #endif /* _ASM_RISCV_ASM_H */ > diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S > index 143a2bb3e697..f24bc4eeedde 100644 > --- a/arch/riscv/kernel/entry.S > +++ b/arch/riscv/kernel/entry.S > @@ -101,6 +101,7 @@ _save_context: > 1: > tail do_trap_unknown > SYM_CODE_END(handle_exception) > +ASM_NOKPROBE(handle_exception) > > /* > * The ret_from_exception must be called with interrupt disabled. Here is the > @@ -167,6 +168,7 @@ SYM_CODE_START_NOALIGN(ret_from_exception) > sret > #endif > SYM_CODE_END(ret_from_exception) > +ASM_NOKPROBE(ret_from_exception) > > #ifdef CONFIG_VMAP_STACK > SYM_CODE_START_LOCAL(handle_kernel_stack_overflow) > @@ -254,6 +256,7 @@ restore_caller_reg: > move a0, sp > tail handle_bad_stack > SYM_CODE_END(handle_kernel_stack_overflow) > +ASM_NOKPROBE(handle_kernel_stack_overflow) > #endif > > SYM_CODE_START(ret_from_fork) > -- > 2.42.0 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
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