On Fri, Sep 06, 2024 at 05:01:51PM -0400, Joe Lawrence wrote:
> On Fri, Sep 06, 2024 at 10:00:08AM -0700, Josh Poimboeuf wrote:
> > On Fri, Sep 06, 2024 at 09:56:06AM -0400, Joe Lawrence wrote:
> > > In the case of klp-diff.c, adding #include <string.h> will provide the
> > > memmem prototype. For both files, I needed to #define _GNU_SOURCE for
> > > that prototype though.
> > >
> > > For the other complaint, I just set struct instruction *dest_insn = NULL
> > > at the top of the for loop, but perhaps the code could be refactored to
> > > clarify the situation to the compiler if you prefer not to do that.
> >
> > Thanks! I'll get these fixed up.
> >
>
> Also, with the workarounds mentioned above, the two you sent to Song,
> and the same .config I attached in the first email, I get the following
> error when trying to build the canonical /proc/cmdline example:
>
> $ cat cmdline-string.patch
> diff --git a/fs/proc/cmdline.c b/fs/proc/cmdline.c
> index a6f76121955f..2bcaf9ec6f78 100644
> --- a/fs/proc/cmdline.c
> +++ b/fs/proc/cmdline.c
> @@ -7,8 +7,7 @@
>
> static int cmdline_proc_show(struct seq_file *m, void *v)
> {
> - seq_puts(m, saved_command_line);
> - seq_putc(m, '\n');
> + seq_printf(m, "%s kpatch=1", saved_command_line);
> return 0;
> }
>
>
> $ ./scripts/livepatch/klp-build ./cmdline-string.patch 2>&1 | tee build2.out
> - klp-build: building original kernel
> vmlinux.o: warning: objtool: init_espfix_bsp+0xab: unreachable instruction
> vmlinux.o: warning: objtool: init_espfix_ap+0x50: unreachable instruction
> vmlinux.o: warning: objtool: syscall_init+0xca: unreachable instruction
> vmlinux.o: warning: objtool: sync_core_before_usermode+0xf: unreachable instruction
> vmlinux.o: warning: objtool: sync_core_before_usermode+0xf: unreachable instruction
> vmlinux.o: warning: objtool: tc_wrapper_init+0x16: unreachable instruction
> vmlinux.o: warning: objtool: pvh_start_xen+0x50: relocation to !ENDBR: pvh_start_xen+0x57
> - klp-build: building patched kernel
> vmlinux.o: warning: objtool: init_espfix_bsp+0xab: unreachable instruction
> vmlinux.o: warning: objtool: init_espfix_ap+0x50: unreachable instruction
> vmlinux.o: warning: objtool: syscall_init+0xca: unreachable instruction
> vmlinux.o: warning: objtool: sync_core_before_usermode+0xf: unreachable instruction
> vmlinux.o: warning: objtool: sync_core_before_usermode+0xf: unreachable instruction
> vmlinux.o: warning: objtool: tc_wrapper_init+0x16: unreachable instruction
> vmlinux.o: warning: objtool: pvh_start_xen+0x50: relocation to !ENDBR: pvh_start_xen+0x57
> - klp-build: diffing objects
> kvm.o: added: __UNIQUE_ID_nop_644
> kvm.o: added: __UNIQUE_ID_nop_645
> kvm.o: added: __UNIQUE_ID_nop_646
> kvm.o: added: __UNIQUE_ID_nop_647
> kvm.o: added: __UNIQUE_ID_nop_648
> kvm.o: added: __UNIQUE_ID_nop_649
> kvm.o: added: __UNIQUE_ID_nop_650
> kvm.o: added: __UNIQUE_ID_nop_651
> kvm.o: added: __UNIQUE_ID_nop_652
> vmlinux.o: changed: cmdline_proc_show
> - klp-build: building patch module
> make[2]: /bin/sh: Argument list too long
> make[2]: *** [scripts/Makefile.build:253: /home/jolawren/src/linux/klp-tmp/out/livepatch.mod] Error 127
> make[1]: *** [/home/jolawren/src/linux/Makefile:1943: /home/jolawren/src/linux/klp-tmp/out] Error 2
> make: *** [Makefile:240: __sub-make] Error 2
> klp-build: error: module build failed
>
> I'm guessing that this happens because of the huge dependency line in
> klp-tmp/out/Kbuild for livepatch-y, it includes over 2000 object files
> (that I'm pretty sure didn't change :)
Hm, did you get this fix?
https://lkml.kernel.org/lkml/20240904070952.kkafz2w5m7wnhblh@treble
--
Josh
