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Christophe de Dinechin 346eb487fc nodemask.h: fix compilation error with GCC12
commit 37462a9203 upstream.

With gcc version 12.0.1 20220401 (Red Hat 12.0.1-0), building with
defconfig results in the following compilation error:

|   CC      mm/swapfile.o
| mm/swapfile.c: In function `setup_swap_info':
| mm/swapfile.c:2291:47: error: array subscript -1 is below array bounds
|  of `struct plist_node[]' [-Werror=array-bounds]
|  2291 |                                 p->avail_lists[i].prio = 1;
|       |                                 ~~~~~~~~~~~~~~^~~
| In file included from mm/swapfile.c:16:
| ./include/linux/swap.h:292:27: note: while referencing `avail_lists'
|   292 |         struct plist_node avail_lists[]; /*
|       |                           ^~~~~~~~~~~

This is due to the compiler detecting that the mask in
node_states[__state] could theoretically be zero, which would lead to
first_node() returning -1 through find_first_bit.

I believe that the warning/error is legitimate.  I first tried adding a
test to check that the node mask is not emtpy, since a similar test exists
in the case where MAX_NUMNODES == 1.

However, adding the if statement causes other warnings to appear in
for_each_cpu_node_but, because it introduces a dangling else ambiguity.
And unfortunately, GCC is not smart enough to detect that the added test
makes the case where (node) == -1 impossible, so it still complains with
the same message.

This is why I settled on replacing that with a harmless, but relatively
useless (node) >= 0 test.  Based on the warning for the dangling else, I
also decided to fix the case where MAX_NUMNODES == 1 by moving the
condition inside the for loop.  It will still only be tested once.  This
ensures that the meaning of an else following for_each_node_mask or
derivatives would not silently have a different meaning depending on the
configuration.

Link: https://lkml.kernel.org/r/20220414150855.2407137-3-dinechin@redhat.com
Signed-off-by: Christophe de Dinechin <christophe@dinechin.org>
Signed-off-by: Christophe de Dinechin <dinechin@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ben Segall <bsegall@google.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-09 10:30:52 +02:00
arch kexec_file: drop weak attribute from arch_kexec_apply_relocations[_add] 2022-06-09 10:30:51 +02:00
block block: Fix potential deadlock in blk_ia_range_sysfs_show() 2022-06-09 10:30:44 +02:00
certs Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
crypto crypto: cryptd - Protect per-CPU resource by disabling BH. 2022-06-09 10:30:30 +02:00
Documentation landlock: Reduce the maximum number of layers to 16 2022-06-09 10:30:47 +02:00
drivers iommu/dma: Fix iova map result check bug 2022-06-09 10:30:51 +02:00
fs ksmbd: fix outstanding credits related bugs 2022-06-09 10:30:51 +02:00
include nodemask.h: fix compilation error with GCC12 2022-06-09 10:30:52 +02:00
init Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug 2022-06-09 10:30:49 +02:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2022-06-09 10:30:30 +02:00
kernel kprobes: Fix build errors with CONFIG_KRETPROBES=n 2022-06-09 10:30:51 +02:00
lib lib/string_helpers: fix not adding strarray to device's resource list 2022-06-09 10:30:49 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm/page_alloc: always attempt to allocate at least one page during bulk allocation 2022-06-09 10:30:52 +02:00
net mac80211: upgrade passive scan to active scan on DFS channels after beacon rx 2022-06-09 10:30:50 +02:00
samples samples/landlock: Format with clang-format 2022-06-09 10:30:46 +02:00
scripts scripts/faddr2line: Fix overlapping text section failures 2022-06-09 10:30:10 +02:00
security ima: remove the IMA_TEMPLATE Kconfig option 2022-06-09 10:30:49 +02:00
sound ASoC: atmel-classd: Remove endianness flag on class d component 2022-06-09 10:30:29 +02:00
tools landlock: Fix same-layer rule unions 2022-06-09 10:30:48 +02:00
usr Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
virt KVM: Free new dirty bitmap if creating a new memslot fails 2022-05-20 13:02:05 -04:00
.clang-format genirq/msi: Make interrupt allocation less convoluted 2021-12-16 22:22:20 +01:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap hotfixes for 5.18-rc7 2022-05-13 10:22:37 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: replace a Microchip AT91 maintainer 2022-02-09 11:30:01 +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 Merge branch 'arm/fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc 2022-05-18 14:07:43 -10:00
Makefile Linux 5.18.2 2022-06-06 08:49:00 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.