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mm: kfence: pass a pointer to virt_to_page() 

Functions that work on a pointer to virtual memory such as virt_to_pfn()
and users of that function such as virt_to_page() are supposed to pass a
pointer to virtual memory, ideally a (void *) or other pointer.  However
since many architectures implement virt_to_pfn() as a macro, this function
becomes polymorphic and accepts both a (unsigned long) and a (void *).

If we instead implement a proper virt_to_pfn(void *addr) function the
following happens (occurred on arch/arm):

mm/kfence/core.c:558:30: warning: passing argument 1
  of 'virt_to_pfn' makes pointer from integer without a
  cast [-Wint-conversion]

In one case we can refer to __kfence_pool directly (and that is a proper
(char *) pointer) and in the other call site we use an explicit cast.

Link: https://lkml.kernel.org/r/20220630084124.691207-4-linus.walleij@linaro.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Linus Walleij 2022-06-30 10:41:22 +02:00 committed by akpm
parent 259ecb34e2
commit 9e7ee421ac
1 changed files with 2 additions and 2 deletions
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4
mm/kfence/core.c
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@ -546,7 +546,7 @@ static unsigned long kfence_init_pool(void)
if (!arch_kfence_init_pool())
return addr;
pages = virt_to_page(addr);
pages = virt_to_page(__kfence_pool);
/*
* Set up object pages: they must have PG_slab set, to avoid freeing
@ -660,7 +660,7 @@ static bool kfence_init_pool_late(void)
/* Same as above. */
free_size = KFENCE_POOL_SIZE - (addr - (unsigned long)__kfence_pool);
#ifdef CONFIG_CONTIG_ALLOC
free_contig_range(page_to_pfn(virt_to_page(addr)), free_size / PAGE_SIZE);
free_contig_range(page_to_pfn(virt_to_page((void *)addr)), free_size / PAGE_SIZE);
#else
free_pages_exact((void *)addr, free_size);
#endif