2022-08-23 18:15:16

by Nathan Chancellor

[permalink] [raw]
Subject: [PATCH -next] mm: pagewalk: Restore err initialization in walk_hugetlb_range()

Clang warns:

mm/pagewalk.c:318:12: error: variable 'err' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
else if (ops->pte_hole)
^~~~~~~~~~~~~
mm/pagewalk.c:321:7: note: uninitialized use occurs here
if (err)
^~~
mm/pagewalk.c:318:8: note: remove the 'if' if its condition is always true
else if (ops->pte_hole)
^~~~~~~~~~~~~~~~~~
mm/pagewalk.c:311:10: note: initialize the variable 'err' to silence this warning
int err;
^
= 0
1 error generated.

Restore the initialization of err to zero so that it cannot be used
uninitialized.

Fixes: 9ce1db56225a ("mm: pagewalk: make error checks more obvious")
Link: https://github.com/ClangBuiltLinux/linux/issues/1694
Signed-off-by: Nathan Chancellor <[email protected]>
---

I am sure that SHA is not stable and I expect this to be squashed into
the original change.

mm/pagewalk.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 54b2a1beeeb3..76e5ccda8c88 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -308,7 +308,7 @@ static int walk_hugetlb_range(unsigned long addr, unsigned long end,
const struct mm_walk_ops *ops = walk->ops;

for (; addr < end; addr = next) {
- int err;
+ int err = 0;
pte_t *pte = huge_pte_offset(walk->mm, addr & hmask, sz);

next = hugetlb_entry_end(h, addr, end);

base-commit: d711de4adbec4cb0b8769bcae971b13293e6d311
--
2.37.2


2022-08-24 05:50:52

by Rolf Eike Beer

[permalink] [raw]
Subject: Re: [PATCH -next] mm: pagewalk: Restore err initialization in walk_hugetlb_range()

Am Dienstag, 23. August 2022, 17:30:56 CEST schrieb Nathan Chancellor:

> Restore the initialization of err to zero so that it cannot be used
> uninitialized.

There are actually 3 places that need fixing. I'll send a patch in a minute.

Eike


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