On Fri, Mar 07, 2025 at 10:26:25PM +0100, Nathan Chancellor wrote:
> On Wed, Mar 05, 2025 at 06:48:26PM +0100, Greg Kroah-Hartman wrote:
> > 6.13-stable review patch. If anyone has any objections, please let me know.
> >
> > ------------------
> >
> > From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> >
> > [ Upstream commit 06e24745985c8dd0da18337503afcf2f2fdbdff1 ]
> >
> > There are no users of annotate_reachable() left.
>
> This is not true in 6.13.y because it was taken without upstream commit
> 624bde3465f6 ("loongarch: Use ASM_REACHABLE"), resulting in:
>
> In file included from include/linux/bug.h:5,
> from include/linux/thread_info.h:13,
> from include/asm-generic/current.h:6,
> from ./arch/loongarch/include/generated/asm/current.h:1,
> from include/linux/sched.h:12,
> from arch/loongarch/kernel/asm-offsets.c:8:
> include/linux/thread_info.h: In function 'check_copy_size':
> arch/loongarch/include/asm/bug.h:47:9: error: implicit declaration of function 'annotate_reachable' [-Wimplicit-function-declaration]
> 47 | annotate_reachable(); \
> | ^~~~~~~~~~~~~~~~~~
> include/asm-generic/bug.h:113:17: note: in expansion of macro '__WARN_FLAGS'
> 113 | __WARN_FLAGS(BUGFLAG_ONCE | \
> | ^~~~~~~~~~~~
> include/linux/thread_info.h:262:13: note: in expansion of macro 'WARN_ON_ONCE'
> 262 | if (WARN_ON_ONCE(bytes > INT_MAX))
> | ^~~~~~~~~~~~
>
> when trying to build ARCH=loongarch now. That applies cleanly and
> resolves the build failure.
>
> > And the annotate_unreachable() usage in unreachable() is plain wrong;
> > it will hide dangerous fall-through code-gen.
>
> This may be reason enough to take this patch into stable... (but then
> why wasn't it Cc'd in the first place, the tip folks are usually good
> about that?)
>
> > Remove both.
> >
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> > Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> > Link: https://lore.kernel.org/r/20241128094312.235637588@xxxxxxxxxxxxx
> > Stable-dep-of: 73cfc53cc3b6 ("objtool: Fix C jump table annotations for Clang")
>
> But I do not think avoiding the conflict generated by this patch is...
> With the "diff3" merge.conflictstyle setting in git, I only see this
> conflict in that change:
>
> /* Annotate a C jump table to allow objtool to follow the code flow */
> <<<<<<< HEAD
> #define __annotate_jump_table __section(".rodata..c_jump_table,\"a\",@progbits #")
>
> ||||||| parent of 73cfc53cc3b6 (objtool: Fix C jump table annotations for Clang)
> #define __annotate_jump_table __section(".rodata..c_jump_table,\"a\",@progbits #")
> =======
> #define __annotate_jump_table __section(".data.rel.ro.c_jump_table")
> >>>>>>> 73cfc53cc3b6 (objtool: Fix C jump table annotations for Clang)
>
> which seems incredibly simple to resolve without dragging in two extra
> patches.
>
> If we do want to keep this change in 6.13.y, maybe it would be worth
> dragging in
>
> 2190966fbc14 ("x86: Convert unreachable() to BUG()")
> 41a1e976623e ("x86/mm: Convert unreachable() to BUG()")
>
> as well?
Both are already in the release, thanks!
greg k-h
