Messages in this thread Patch in this message | | | Date | Wed, 13 Oct 2021 11:16:57 -0700 | Subject | [PATCH v5 14/15] x86, kprobes: Fix optprobe_template_func type mismatch | From | Sami Tolvanen <> |
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The optprobe_template_func symbol is defined in inline assembly, but it's not marked global, which conflicts with the C declaration needed for STACK_FRAME_NON_STANDARD and confuses the compiler when CONFIG_CFI_CLANG is enabled.
Marking the symbol global would make the compiler happy, but as the compiler also generates a CFI jump table entry for all address-taken functions, the jump table ends up containing a jump to the .rodata section where optprobe_template_func resides, which results in an objtool warning.
Use ASM_STACK_FRAME_NON_STANDARD instead to avoid both issues.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> --- arch/x86/kernel/kprobes/opt.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index 71425ebba98a..95375ef5deee 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -103,6 +103,7 @@ static void synthesize_set_arg1(kprobe_opcode_t *addr, unsigned long val) asm ( ".pushsection .rodata\n" "optprobe_template_func:\n" + ASM_STACK_FRAME_NON_STANDARD(optprobe_template_func) ".global optprobe_template_entry\n" "optprobe_template_entry:\n" #ifdef CONFIG_X86_64 @@ -154,9 +155,6 @@ asm ( "optprobe_template_end:\n" ".popsection\n"); -void optprobe_template_func(void); -STACK_FRAME_NON_STANDARD(optprobe_template_func); - #define TMPL_CLAC_IDX \ ((long)optprobe_template_clac - (long)optprobe_template_entry) #define TMPL_MOVE_IDX \ -- 2.33.0.1079.g6e70778dc9-goog
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