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Siddh Raman Pant 94398c1fec x86/numa: Use cpumask_available instead of hardcoded NULL check 
[ Upstream commit 625395c4a0 ]

GCC-12 started triggering a new warning:

  arch/x86/mm/numa.c: In function ‘cpumask_of_node’:
  arch/x86/mm/numa.c:916:39: warning: the comparison will always evaluate as ‘false’ for the address of ‘node_to_cpumask_map’ will never be NULL [-Waddress]
    916 |         if (node_to_cpumask_map[node] == NULL) {
        |                                       ^~

node_to_cpumask_map is of type cpumask_var_t[].

When CONFIG_CPUMASK_OFFSTACK is set, cpumask_var_t is typedef'd to a
pointer for dynamic allocation, else to an array of one element. The
"wicked game" can be checked on line 700 of include/linux/cpumask.h.

The original code in debug_cpumask_set_cpu() and cpumask_of_node() were
probably written by the original authors with CONFIG_CPUMASK_OFFSTACK=y
(i.e. dynamic allocation) in mind, checking if the cpumask was available
via a direct NULL check.

When CONFIG_CPUMASK_OFFSTACK is not set, GCC gives the above warning
while compiling the kernel.

Fix that by using cpumask_available(), which does the NULL check when
CONFIG_CPUMASK_OFFSTACK is set, otherwise returns true. Use it wherever
such checks are made.

Conditional definitions of cpumask_available() can be found along with
the definition of cpumask_var_t. Check the cpumask.h reference mentioned
above.

Fixes: c032ef60d1 ("cpumask: convert node_to_cpumask_map[] to cpumask_var_t")
Fixes: de2d9445f1 ("x86: Unify node_to_cpumask_map handling between 32 and 64bit")
Signed-off-by: Siddh Raman Pant <code@siddh.me>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20220731160913.632092-1-code@siddh.me
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-21 15:16:12 +02:00
arch x86/numa: Use cpumask_available instead of hardcoded NULL check 2022-08-21 15:16:12 +02:00
block block: remove the request_queue to argument request based tracepoints 2022-08-21 15:15:36 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:13:17 +02:00
crypto crypto: memneq - move into lib/ 2022-06-22 14:13:18 +02:00
Documentation vfio: Split creation of a vfio_device into init and register ops 2022-08-21 15:16:07 +02:00
drivers video: fbdev: sis: fix typos in SiS_GetModeID() 2022-08-21 15:16:10 +02:00
fs f2fs: fix to remove F2FS_COMPR_FL and tag F2FS_NOCOMP_FL at the same time 2022-08-21 15:16:11 +02:00
include sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed 2022-08-21 15:16:12 +02:00
init Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug 2022-06-09 10:21:25 +02:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2022-06-09 10:21:17 +02:00
kernel sched, cpuset: Fix dl_cpu_busy() panic due to empty cs->cpus_allowed 2022-08-21 15:16:12 +02:00
lib lib/smp_processor_id: fix imbalanced instrumentation_end() call 2022-08-21 15:16:08 +02:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
mm mm/mmap.c: fix missing call to vm_unacct_memory in mmap_region 2022-08-21 15:16:02 +02:00
net dccp: put dccp_qpolicy_full() and dccp_qpolicy_push() in the same lock 2022-08-21 15:15:52 +02:00
samples x86: Prepare inline-asm for straight-line-speculation 2022-07-25 11:26:29 +02:00
scripts scripts/faddr2line: Fix vmlinux detection on arm64 2022-08-21 15:16:12 +02:00
security selinux: Add boundary check in put_entry() 2022-08-21 15:15:31 +02:00
sound ASoC: mchp-spdifrx: disable end of block interrupt on failures 2022-08-21 15:16:10 +02:00
tools genelf: Use HAVE_LIBCRYPTO_SUPPORT, not the never defined HAVE_LIBCRYPTO 2022-08-21 15:16:12 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:25:48 +01:00
virt KVM: Don't set Accessed/Dirty bits for ZERO_PAGE 2022-08-21 15:15:54 +02:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: add Amir as xfs maintainer for 5.10.y 2022-07-02 16:39:22 +02:00
Makefile Makefile: link with -z noexecstack --no-warn-rwx-segments 2022-08-21 15:15:18 +02:00
README

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.