From: Jason Yan <yanaijie@huawei.com>
To: <jaegeuk@kernel.org>, <chao@kernel.org>,
<linux-f2fs-devel@lists.sourceforge.net>,
<linux-kernel@vger.kernel.org>
Cc: <kernel-hardening@lists.openwall.com>,
Jason Yan <yanaijie@huawei.com>,
Kees Cook <keescook@chromium.org>, Chao Yu <yuchao0@huawei.com>
Subject: [PATCH] f2fs: Eliminate usage of uninitialized_var() macro
Date: Mon, 15 Jun 2020 16:51:32 +0800 [thread overview]
Message-ID: <20200615085132.166470-1-yanaijie@huawei.com> (raw)
This is an effort to eliminate the uninitialized_var() macro[1].
The use of this macro is the wrong solution because it forces off ANY
analysis by the compiler for a given variable. It even masks "unused
variable" warnings.
Quoted from Linus[2]:
"It's a horrible thing to use, in that it adds extra cruft to the
source code, and then shuts up a compiler warning (even the _reliable_
warnings from gcc)."
Fix it by remove this variable since it is not needed at all.
[1] https://github.com/KSPP/linux/issues/81
[2] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/
Cc: Kees Cook <keescook@chromium.org>
Suggested-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
---
v2: Directly remove this variable.
fs/f2fs/data.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 326c63879ddc..3753ba06531b 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2856,7 +2856,6 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
};
#endif
int nr_pages;
- pgoff_t uninitialized_var(writeback_index);
pgoff_t index;
pgoff_t end; /* Inclusive */
pgoff_t done_index;
@@ -2875,8 +2874,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
clear_inode_flag(mapping->host, FI_HOT_DATA);
if (wbc->range_cyclic) {
- writeback_index = mapping->writeback_index; /* prev offset */
- index = writeback_index;
+ index = mapping->writeback_index; /* prev offset */
end = -1;
} else {
index = wbc->range_start >> PAGE_SHIFT;
--
2.25.4
next reply other threads:[~2020-06-15 8:50 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-15 8:51 Jason Yan [this message]
2020-06-15 9:04 ` [PATCH] f2fs: Eliminate usage of uninitialized_var() macro Chao Yu
2020-06-15 20:11 ` Kees Cook
-- strict thread matches above, loose matches on Subject: below --
2020-06-15 4:02 Jason Yan
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