objtool error in fs/fuse/: unknown CFA base reg -1

["Arnd Bergmann" <arnd@arndb.de>]

[-- Attachment #1: Type: text/plain, Size: 945 bytes --]

Hi Peter and Josh,

Building randconfigs with Debian clang version 1:21.1.8-74, I came
across this failure in fuse:

fs/fuse/readdir.o: warning: objtool: fuse_emit+0x754: undefined stack state
fs/fuse/readdir.o: error: objtool: fuse_emit+0x74d: unknown CFA base reg -1

I've attached the object file and the randconfig that triggered it.
I have not tried to analyze it or reproduce with other compilers at all,
maybe you can see what the problem is already. It looks like the
kernel test robot found this one as well.
Let me know if you need more information.

FWIW, I get almost no objtool warnings otherwise, the only one I saw
recently (once) was with gcc-16.2:
drivers/media/cec/core/cec-adap.o: warning: objtool: cec_receive_notify.isra.0+0x4f0: ignoring unreachables due to jump table quirk
This seems to be the same one I reported previously in
https://lore.kernel.org/all/861ac0a1-c900-4dc2-b30a-d2397096ec06@app.fastmail.com/

     Arnd

[-- Attachment #2: readdir.o.gz --]
[-- Type: application/gzip, Size: 41367 bytes --]

[-- Attachment #3: config-0x154F3AE0.gz --]
[-- Type: application/gzip, Size: 38492 bytes --]