On Sat, Nov 16, 2019 at 09:46:07PM +0100, Borislav Petkov wrote: > WARNING: vmlinux.o(.text+0x8c0b1): Section mismatch in reference from the function ftrace_modify_code_direct() to the function .init.text:text_poke_early() > The function ftrace_modify_code_direct() references > the function __init text_poke_early(). > This is often because ftrace_modify_code_direct lacks a __init > annotation or the annotation of text_poke_early is wrong. > > FATAL: modpost: Section mismatches detected. > Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them. > make[1]: *** [scripts/Makefile.modpost:66: __modpost] Error 1 > make: *** [Makefile:1077: vmlinux] Error 2 Here's a fix suggested by Peter: --- From: Borislav Petkov <bp@xxxxxxx> Subject: [PATCH] x86/ftrace: Mark ftrace_modify_code_direct() __ref ... because it calls the .init.text function text_poke_early(). That is ok because it does call that function early, during boot. Fixes: 9706f7c3531f ("x86/ftrace: Use text_poke()") Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Cc: Alexei Starovoitov <ast@xxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: https://lkml.kernel.org/r/20191116204607.GC23231@xxxxxxx --- arch/x86/kernel/ftrace.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index 2a179fb35cd1..108ee96f8b66 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -99,7 +99,12 @@ static int ftrace_verify_code(unsigned long ip, const char *old_code) return 0; } -static int +/* + * Marked __ref because it calls text_poke_early() which is .init.text. That is + * ok because that call will happen early, during boot, when .init sections are + * still present. + */ +static int __ref ftrace_modify_code_direct(unsigned long ip, const char *old_code, const char *new_code) { -- 2.21.0 -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
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