| Message ID | 20231004131009.409193-1-cleger@rivosinc.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 5014396af9bbac0f28d9afee7eae405206d01ee7 |
| Headers | show |
| Series | riscv: blacklist assembly symbols for kprobe | expand |
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>
Hello: This patch was applied to riscv/linux.git (for-next) by Palmer Dabbelt <palmer@rivosinc.com>: On Wed, 4 Oct 2023 15:10:09 +0200 you 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() > > [...] Here is the summary with links: - riscv: blacklist assembly symbols for kprobe https://git.kernel.org/riscv/c/5014396af9bb You are awesome, thank you!
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)
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(+)