linux/arch
Vincent Mailhol 9ce02f0fc6 x86/bug: Prevent shadowing in __WARN_FLAGS
The macro __WARN_FLAGS() uses a local variable named "f". This being a
common name, there is a risk of shadowing other variables.

For example, GCC would yield:

| In file included from ./include/linux/bug.h:5,
|                  from ./include/linux/cpumask.h:14,
|                  from ./arch/x86/include/asm/cpumask.h:5,
|                  from ./arch/x86/include/asm/msr.h:11,
|                  from ./arch/x86/include/asm/processor.h:22,
|                  from ./arch/x86/include/asm/timex.h:5,
|                  from ./include/linux/timex.h:65,
|                  from ./include/linux/time32.h:13,
|                  from ./include/linux/time.h:60,
|                  from ./include/linux/stat.h:19,
|                  from ./include/linux/module.h:13,
|                  from virt/lib/irqbypass.mod.c:1:
| ./include/linux/rcupdate.h: In function 'rcu_head_after_call_rcu':
| ./arch/x86/include/asm/bug.h:80:21: warning: declaration of 'f' shadows a parameter [-Wshadow]
|    80 |         __auto_type f = BUGFLAG_WARNING|(flags);                \
|       |                     ^
| ./include/asm-generic/bug.h:106:17: note: in expansion of macro '__WARN_FLAGS'
|   106 |                 __WARN_FLAGS(BUGFLAG_ONCE |                     \
|       |                 ^~~~~~~~~~~~
| ./include/linux/rcupdate.h:1007:9: note: in expansion of macro 'WARN_ON_ONCE'
|  1007 |         WARN_ON_ONCE(func != (rcu_callback_t)~0L);
|       |         ^~~~~~~~~~~~
| In file included from ./include/linux/rbtree.h:24,
|                  from ./include/linux/mm_types.h:11,
|                  from ./include/linux/buildid.h:5,
|                  from ./include/linux/module.h:14,
|                  from virt/lib/irqbypass.mod.c:1:
| ./include/linux/rcupdate.h:1001:62: note: shadowed declaration is here
|  1001 | rcu_head_after_call_rcu(struct rcu_head *rhp, rcu_callback_t f)
|       |                                               ~~~~~~~~~~~~~~~^

For reference, sparse also warns about it, c.f. [1].

This patch renames the variable from f to __flags (with two underscore
prefixes as suggested in the Linux kernel coding style [2]) in order
to prevent collisions.

[1] https://lore.kernel.org/all/CAFGhKbyifH1a+nAMCvWM88TK6fpNPdzFtUXPmRGnnQeePV+1sw@mail.gmail.com/

[2] Linux kernel coding style, section 12) Macros, Enums and RTL,
paragraph 5) namespace collisions when defining local variables in
macros resembling functions
https://www.kernel.org/doc/html/latest/process/coding-style.html#macros-enums-and-rtl

Fixes: bfb1a7c91f ("x86/bug: Merge annotate_reachable() into_BUG_FLAGS() asm")
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20220324023742.106546-1-mailhol.vincent@wanadoo.fr
2022-04-05 10:24:40 +02:00
..
alpha Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-04-01 19:57:03 -07:00
arc ptrace: Cleanups for v5.18 2022-03-28 17:29:53 -07:00
arm ARM fixes for 5.18-rc1: 2022-04-03 10:17:48 -07:00
arm64 SoC: fixes for 5.18, part 1 2022-04-01 13:21:19 -07:00
csky ptrace: Cleanups for v5.18 2022-03-28 17:29:53 -07:00
h8300 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-04-01 19:57:03 -07:00
hexagon ptrace: Cleanups for v5.18 2022-03-28 17:29:53 -07:00
ia64 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-04-01 19:57:03 -07:00
m68k Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-04-01 19:57:03 -07:00
microblaze Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
mips - build fix for gpio 2022-04-02 12:14:38 -07:00
nios2 ptrace: Cleanups for v5.18 2022-03-28 17:29:53 -07:00
openrisc ptrace: Cleanups for v5.18 2022-03-28 17:29:53 -07:00
parisc Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
powerpc Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-04-01 19:57:03 -07:00
riscv RISC-V Patches for the 5.18 Merge Window, Part 2 2022-04-01 13:31:57 -07:00
s390 * Only do MSR filtering for MSRs accessed by rdmsr/wrmsr 2022-04-02 12:09:02 -07:00
sh Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2022-04-01 19:57:03 -07:00
sparc Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
um Kbuild fixes for v5.18 2022-04-02 12:33:31 -07:00
x86 x86/bug: Prevent shadowing in __WARN_FLAGS 2022-04-05 10:24:40 +02:00
xtensa Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
.gitignore
Kconfig Networking fixes for 5.18-rc1 and rethook patches. 2022-03-31 11:23:31 -07:00