Re: clang/objtool failures on linux-next

[Josh Poimboeuf]

On Fri, Mar 06, 2026 at 01:41:59PM +0100, Arnd Bergmann wrote:
> I came across two randconfig builds on linux-next that fail to build:
> 
> ==> build/x86/0xCE0DD5F4_defconfig/log <==
> drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: undefined stack state
> drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: unknown CFA base reg -1
> 
> ==> build/x86/0xAE77DEF6_defconfig/log <==
> drivers/scsi/qla2xxx/qla_dbg.o: error: SIGSEGV: objtool stack overflow!
> Segmentation fault
> 
> The first one happens with clang-18 through clang-22, the second one
> with all versions of clang.
> 
> The crash seems worse at first, but I also noticed that
> clang takes a long time to actually compile it, and the object
> file is huge, so this is probably partially a compiler problem.
> 
> Please have a look at the attached object files along the configs
> I used.

Thanks, I'll post a fix for the 1st one right now (haven't looked at the
stack overflow yet).


-- 
Josh