Re: Boot Warning

[Mike Lothian]

That patch does indeed make the warning go away :D

Is there anything else you need from me?

On Mon, 22 Jul 2024 at 16:23, Borislav Petkov <bp@xxxxxxxxx> wrote:
>
> On Mon, Jul 22, 2024 at 01:45:35PM +0100, Mike Lothian wrote:
> > Hi
> >
> > I'm seeing the following boot warning:
> >
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 0 at arch/x86/lib/cmdline.c:211
> > cmdline_find_option_bool+0x741/0x760
> > Modules linked in:
> > CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.10.0-tip+ #4105
> > RIP: 0010:cmdline_find_option_bool+0x741/0x760
> > Code: 85 07 f9 ff ff eb 20 41 80 f8 21 72 1c 45 31 c9 41 80 f8 21 41
> > 0f 93 c1 45 01 c9 81 f9 00 08 00 00 0f 85 e5 f8 ff ff 31 c0 c3 <0f> 0b
> > 48 85 ff 0f 85 ce f8 ff ff b8 ff ff ff ff c3 cc cc cc cc cc
> > RSP: 0000:ffffffff83803f18 EFLAGS: 00010046 ORIG_RAX: 0000000000000000
> > RAX: 000000000a50000c RBX: 0000000068747541 RCX: ffffffff833f2bec
> > RDX: 0000000000000000 RSI: ffffffff832def4e RDI: ffffffff83b98820
> > RBP: 0000000000a50f00 R08: 00cf9a000000ffff R09: 0000000000000030
> > R10: 000000006c617470 R11: 0000000000100000 R12: 0000000000000000
> > R13: 0000000000000000 R14: 00000000b53e4000 R15: 00000000b53e4000
> > FS:  0000000000000000(0000) GS:ffffffff83acd000(0000) knlGS:0000000000000000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: ffff8880b61c6810 CR3: 0000000004b57000 CR4: 00000000000000b0
> > Call Trace:
> > <TASK>
> > ? __warn+0xcb/0x1c0
> > ? cmdline_find_option_bool+0x741/0x760
> > ? report_bug+0x173/0x220
> > ? early_fixup_exception+0x4a/0xa0
> > ? early_idt_handler_common+0x2f/0x40
> > ? cmdline_find_option_bool+0x741/0x760
> > ? check_loader_disabled_bsp+0x46/0xa0
> > ? load_ucode_bsp+0x6b/0x80
> > ? x86_64_start_kernel+0x4b/0x70
> > ? common_startup_64+0x12c/0x137
> > </TASK>
> > ---[ end trace 0000000000000000 ]---
> >
> > I use an efi stub kernel
> > https://github.com/FireBurn/KernelStuff/blob/master/dot_config_tip
> >
> > I wasn't quite sure where to report this in the bugzilla, I'll happily
> > raise one if you let me know which section it should be in
>
> Yeah, you can usually CC x86@ and lkml and that is fine too - bugzilla is not
> absolutely required. Did that now.
>
> Anyway, yeah, this is nasty. Our handling of the merging of the builtin and
> boot cmdline options would need some serious reshuffling to fix this: the
> ucode loader needs to parse cmdline but the final cmdline is built a lot
> later.
>
> The only easy thing I could think of right now is, well, to check both cmdline
> strings before the merging happens.
>
> Something like the completely untested below:
>
> ---
>  arch/x86/include/asm/cmdline.h |  4 ++++
>  arch/x86/kernel/setup.c        |  2 +-
>  arch/x86/lib/cmdline.c         | 27 ++++++++++++++++++++-------
>  3 files changed, 25 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/include/asm/cmdline.h b/arch/x86/include/asm/cmdline.h
> index 6faaf27e8899..abcb270e2a07 100644
> --- a/arch/x86/include/asm/cmdline.h
> +++ b/arch/x86/include/asm/cmdline.h
> @@ -2,6 +2,10 @@
>  #ifndef _ASM_X86_CMDLINE_H
>  #define _ASM_X86_CMDLINE_H
>
> +#include <asm/setup.h>
> +
> +extern char __initdata builtin_cmdline[COMMAND_LINE_SIZE];
> +
>  int cmdline_find_option_bool(const char *cmdline_ptr, const char *option);
>  int cmdline_find_option(const char *cmdline_ptr, const char *option,
>                         char *buffer, int bufsize);
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 5d34cad9b7b1..6129dc2ba784 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -164,7 +164,7 @@ unsigned long saved_video_mode;
>
>  static char __initdata command_line[COMMAND_LINE_SIZE];
>  #ifdef CONFIG_CMDLINE_BOOL
> -static char __initdata builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
> +char builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
>  bool builtin_cmdline_added __ro_after_init;
>  #endif
>
> diff --git a/arch/x86/lib/cmdline.c b/arch/x86/lib/cmdline.c
> index 384da1fdd5c6..75e7e2cc4569 100644
> --- a/arch/x86/lib/cmdline.c
> +++ b/arch/x86/lib/cmdline.c
> @@ -207,18 +207,31 @@ __cmdline_find_option(const char *cmdline, int max_cmdline_size,
>
>  int cmdline_find_option_bool(const char *cmdline, const char *option)
>  {
> -       if (IS_ENABLED(CONFIG_CMDLINE_BOOL))
> -               WARN_ON_ONCE(!builtin_cmdline_added);
> +       int ret;
>
> -       return __cmdline_find_option_bool(cmdline, COMMAND_LINE_SIZE, option);
> +       ret = __cmdline_find_option_bool(cmdline, COMMAND_LINE_SIZE, option);
> +       if (ret > 0)
> +               return ret;
> +
> +#ifdef CONFIG_CMDLINE_BOOL
> +       if (!builtin_cmdline_added)
> +               ret = __cmdline_find_option_bool(builtin_cmdline, COMMAND_LINE_SIZE, option);
> +#endif
> +       return ret;
>  }
>
>  int cmdline_find_option(const char *cmdline, const char *option, char *buffer,
>                         int bufsize)
>  {
> -       if (IS_ENABLED(CONFIG_CMDLINE_BOOL))
> -               WARN_ON_ONCE(!builtin_cmdline_added);
> +       int ret;
> +
> +       ret = __cmdline_find_option(cmdline, COMMAND_LINE_SIZE, option, buffer, bufsize);
> +       if (ret > 0)
> +               return ret;
>
> -       return __cmdline_find_option(cmdline, COMMAND_LINE_SIZE, option,
> -                                    buffer, bufsize);
> +#ifdef CONFIG_CMDLINE_BOOL
> +       if (!builtin_cmdline_added)
> +               ret = __cmdline_find_option(builtin_cmdline, COMMAND_LINE_SIZE, option, buffer, bufsize);
> +#endif
> +       return ret;
>  }
> --
> 2.43.0
>
>
> --
> Regards/Gruss,
>     Boris.
>
> https://people.kernel.org/tglx/notes-about-netiquette