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authorAlexei Starovoitov <ast@kernel.org>2020-08-27 15:01:10 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2020-08-28 21:20:32 +0200
commit76cd61739fd107a7f7ec4c24a045e98d8ee150f0 (patch)
tree62d8464d469978b7a64b29164b877194075fd68e /mm/filemap.c
parentd557ea39a5f894630c403b78703ac92b08b7dd62 (diff)
downloadlinux-76cd61739fd107a7f7ec4c24a045e98d8ee150f0.tar.bz2
mm/error_inject: Fix allow_error_inject function signatures.
'static' and 'static noinline' function attributes make no guarantees that gcc/clang won't optimize them. The compiler may decide to inline 'static' function and in such case ALLOW_ERROR_INJECT becomes meaningless. The compiler could have inlined __add_to_page_cache_locked() in one callsite and didn't inline in another. In such case injecting errors into it would cause unpredictable behavior. It's worse with 'static noinline' which won't be inlined, but it still can be optimized. Like the compiler may decide to remove one argument or constant propagate the value depending on the callsite. To avoid such issues make sure that these functions are global noinline. Fixes: af3b854492f3 ("mm/page_alloc.c: allow error injection") Fixes: cfcbfb1382db ("mm/filemap.c: enable error injection at add_to_page_cache()") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Link: https://lore.kernel.org/bpf/20200827220114.69225-2-alexei.starovoitov@gmail.com
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 1aaea26556cc..054d93a86f8a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -827,10 +827,10 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
}
EXPORT_SYMBOL_GPL(replace_page_cache_page);
-static int __add_to_page_cache_locked(struct page *page,
- struct address_space *mapping,
- pgoff_t offset, gfp_t gfp_mask,
- void **shadowp)
+noinline int __add_to_page_cache_locked(struct page *page,
+ struct address_space *mapping,
+ pgoff_t offset, gfp_t gfp_mask,
+ void **shadowp)
{
XA_STATE(xas, &mapping->i_pages, offset);
int huge = PageHuge(page);