Re: clang/objtool failures on linux-next

[Josh Poimboeuf]

On Fri, Mar 06, 2026 at 09:31:02AM -0800, Josh Poimboeuf wrote:
> 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).

Both fixes posted now:

https://lore.kernel.org/240e6a172cc73292499334a3724d02ccb3247fc7.1772818491.git.jpoimboe@xxxxxxxxxx
https://lore.kernel.org/8b97f62d083457f3b0a29a424275f7957dd3372f.1772821683.git.jpoimboe@xxxxxxxxxx

-- 
Josh