Re: radeon.ko/i586: BUG: kernel NULL pointer dereference,address:00000004

[Steven Rostedt]

On Sat, 22 Jul 2023 11:30:14 +0900
<kabe@xxxxxxxxxxx> wrote:

> >> diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
> >> index 897cf02c20b1..801f4414da3e 100644
> >> --- a/arch/x86/include/asm/ftrace.h
> >> +++ b/arch/x86/include/asm/ftrace.h
> >> @@ -13,7 +13,7 @@
> >>  #ifdef CONFIG_HAVE_FENTRY
> >>  # include <asm/ibt.h>
> >>  /* Add offset for endbr64 if IBT enabled */
> >> -# define FTRACE_MCOUNT_MAX_OFFSET	ENDBR_INSN_SIZE
> >> +# define FTRACE_MCOUNT_MAX_OFFSET	(ENDBR_INSN_SIZE + MCOUNT_INSN_SIZE)
> >>  #endif
> >>  
> >>  #ifdef CONFIG_DYNAMIC_FTRACE
> >>   
> 
> Above patch didn't work, but
> Does it matter that I am compiling with "gcc -fcf-protection=none"
> to not emit endbr32 instructions for i586?

This patch is supposed to address the case when ENDBR_INSN_SIZE is
zero. So I would think that that wouldn't matter.

-- Steve