Messages in this thread | | | From | Waiman Long <> | Subject | Re: [PATCH-next] mm/memcontrol.c: Fix potential uninitialized variable warning | Date | Wed, 26 May 2021 18:29:02 -0400 |
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On 5/26/21 4:43 PM, Andrew Morton wrote: > On Wed, 26 May 2021 15:36:02 -0400 Waiman Long <longman@redhat.com> wrote: > >> If the -Wno-maybe-uninitialized gcc option is not specified, compilation >> of memcontrol.c may generate the following warnings: >> >> mm/memcontrol.c: In function ‘refill_obj_stock’: >> ./arch/x86/include/asm/irqflags.h:127:17: warning: ‘flags’ may be used uninitialized in this function [-Wmaybe-uninitialized] >> return !(flags & X86_EFLAGS_IF); >> ~~~~~~~^~~~~~~~~~~~~~~~ >> mm/memcontrol.c:3216:16: note: ‘flags’ was declared here >> unsigned long flags; >> ^~~~~ >> In file included from mm/memcontrol.c:29: >> mm/memcontrol.c: In function ‘uncharge_page’: >> ./include/linux/memcontrol.h:797:2: warning: ‘objcg’ may be used uninitialized in this function [-Wmaybe-uninitialized] >> percpu_ref_put(&objcg->refcnt); >> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> >> Fix that by properly initializing *pflags in get_obj_stock() and >> introducing a use_objcg bool variable in uncharge_page() to avoid >> potentially accessing the struct page data twice. >> > Thanks. I'll queue this as a fix against your "mm/memcg: optimize user > context object stock access". > Thanks for that.
Cheers, Longman
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