Re: clang/objtool failures on linux-next

[Josh Poimboeuf]

On Fri, Mar 06, 2026 at 11:04:50PM +0100, Arnd Bergmann wrote:
> ==> build/x86/0x8FD83285_defconfig/log <==
> drivers/gpu/drm/amd/amdgpu/amdgpu_cs.o: warning: objtool: amdgpu_cs_parser_bos+0x723: unreachable instruction
> drivers/gpu/drm/xe/xe_bo.o: warning: objtool: xe_bo_create_pin_map_at_novm+0x11d: unreachable instruction
> drivers/gpu/drm/panthor/panthor_drv.o: warning: objtool: panthor_ioctl_vm_bind+0x2df: unreachable instruction

These three warnings are accurate, for each of these, Clang is leaving
an unreachable JMP at the end of the function:

    166e:	4c 89 ea             	mov    %r13,%rdx
    1671:	e8 00 00 00 00       	call   1676 <amdgpu_cs_parser_bos+0x716>	1672: R_X86_64_PLT32	__ubsan_handle_shift_out_of_bounds-0x4
    1676:	49 8b 94 24 08 1d 01 00 	mov    0x11d08(%r12),%rdx
    167e:	e9 c6 fd ff ff       	jmp    1449 <amdgpu_cs_parser_bos+0x4e9>
    1683:	e9 8c f9 ff ff       	jmp    1014 <amdgpu_cs_parser_bos+0xb4>
    1688:	0f 1f 84 00 00 00 00 00 	nopl   0x0(%rax,%rax,1)

Nathan, any idea?  I haven't seen this pattern before.

-- 
Josh