next-20241114: clang: fs/netfs/read_retry.c:235:20: error: variable 'subreq' is uninitialized when used here [-Werror,-Wuninitialized]

[Naresh Kamboju]

The following builds failed with clang-19 and clang-nightly on the
Linux next-20241114 and next-20241115 tags on x86 architecture.
But the build passed with gcc-13.

First seen on Linux next-20241114 tag.
  Good: next-20241113
  Bad:  next-20241114

build:
  * clang-19-lkftconfig
  * clang-nightly-lkftconfig

Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>

Build log:
---------
fs/netfs/read_retry.c:235:20: error: variable 'subreq' is
uninitialized when used here [-Werror,-Wuninitialized]
  235 |         if (list_is_last(&subreq->rreq_link, &stream->subrequests))
      |                           ^~~~~~
fs/netfs/read_retry.c:28:36: note: initialize the variable 'subreq' to
silence this warning
   28 |         struct netfs_io_subrequest *subreq;
      |                                           ^
      |                                            = NULL
1 error generated.
make[5]: *** [scripts/Makefile.build:229: fs/netfs/read_retry.o] Error 1

Build image:
-----------
- https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20241114/testrun/25811023/suite/build/test/clang-19-lkftconfig/details/
- https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20241114/testrun/25811023/suite/build/test/clang-19-lkftconfig/log
- https://storage.tuxsuite.com/public/linaro/lkft/builds/2opUctayqtTsKWUeLDYKbGaUqa9/

Steps to reproduce:
------------
- tuxmake --runtime podman --target-arch x86_64 --toolchain clang-19
--kconfig https://storage.tuxsuite.com/public/linaro/lkft/builds/2opUctayqtTsKWUeLDYKbGaUqa9/config
LLVM=1 LLVM_IAS=1

metadata:
----
  git describe: next-20241114
  git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
  git sha: 37c5695cb37a20403947062be8cb7e00f6bed353
  kernel config:
https://storage.tuxsuite.com/public/linaro/lkft/builds/2opUctayqtTsKWUeLDYKbGaUqa9/config
  build url: https://storage.tuxsuite.com/public/linaro/lkft/builds/2opUctayqtTsKWUeLDYKbGaUqa9/
  toolchain: clang-19
  config: lkftconfig
  arch: x86_64

--
Linaro LKFT
https://lkft.linaro.org