6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Clément Léger <cleger@xxxxxxxxxxxx> [ Upstream commit 5014396af9bbac0f28d9afee7eae405206d01ee7 ] 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@xxxxxxxxxxxx> Reviewed-by: Charlie Jenkins <charlie@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20231004131009.409193-1-cleger@xxxxxxxxxxxx Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 bfb4c26f113c4..b5b84c6be01e1 100644 --- a/arch/riscv/include/asm/asm.h +++ b/arch/riscv/include/asm/asm.h @@ -164,6 +164,16 @@ 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 278d01d2911fd..ed7baf2cf7e87 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -105,6 +105,7 @@ _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 @@ -171,6 +172,7 @@ 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) @@ -206,6 +208,7 @@ SYM_CODE_START_LOCAL(handle_kernel_stack_overflow) 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) -- 2.43.0
