Messages in this thread | | | Date | Tue, 30 May 2023 08:20:16 -0700 | From | Nathan Chancellor <> | Subject | Re: [PATCH] x86/csum: Move csum_tail result parameter to a local variable. |
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Hi Tom,
On Tue, May 30, 2023 at 09:59:53AM -0400, Tom Rix wrote: > clang with W=1 reports > arch/x86/lib/csum-partial_64.c:74:20: error: variable > 'result' is uninitialized when used here [-Werror,-Wuninitialized] > return csum_tail(result, temp64, odd); > ^~~~~~ > This is a false positive, but there is never an intermediate value > of result to pass into csum_trail, so move the parameter result to > a local variable. > > Signed-off-by: Tom Rix <trix@redhat.com>
Thanks for the patch. I sent the same one last Friday, which should be in your inbox:
https://lore.kernel.org/20230526-csum_partial-wuninitialized-v1-1-ebc0108dcec1@kernel.org/
Dave picked it up yesterday, I guess -tip's auto-latest was not refreshed for today's -next:
https://git.kernel.org/tip/2fe1e67e6987b6f05329740da79c8150a2205b0d
Cheers, Nathan
> --- > arch/x86/lib/csum-partial_64.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/lib/csum-partial_64.c b/arch/x86/lib/csum-partial_64.c > index fe5861951b15..cea25ca8b8cf 100644 > --- a/arch/x86/lib/csum-partial_64.c > +++ b/arch/x86/lib/csum-partial_64.c > @@ -21,8 +21,10 @@ static inline unsigned short from32to16(unsigned a) > return b; > } > > -static inline __wsum csum_tail(unsigned int result, u64 temp64, int odd) > +static inline __wsum csum_tail(u64 temp64, int odd) > { > + unsigned int result; > + > result = add32_with_carry(temp64 >> 32, temp64 & 0xffffffff); > if (unlikely(odd)) { > result = from32to16(result); > @@ -45,7 +47,7 @@ static inline __wsum csum_tail(unsigned int result, u64 temp64, int odd) > __wsum csum_partial(const void *buff, int len, __wsum sum) > { > u64 temp64 = (__force u64)sum; > - unsigned odd, result; > + unsigned odd; > > odd = 1 & (unsigned long) buff; > if (unlikely(odd)) { > @@ -71,7 +73,7 @@ __wsum csum_partial(const void *buff, int len, __wsum sum) > "adcq $0,%[res]" > : [res] "+r"(temp64) > : [src] "r"(buff), "m"(*(const char(*)[40])buff)); > - return csum_tail(result, temp64, odd); > + return csum_tail(temp64, odd); > } > if (unlikely(len >= 64)) { > /* > @@ -141,7 +143,7 @@ __wsum csum_partial(const void *buff, int len, __wsum sum) > : [res] "+r"(temp64) > : [trail] "r"(trail)); > } > - return csum_tail(result, temp64, odd); > + return csum_tail(temp64, odd); > } > EXPORT_SYMBOL(csum_partial); > > -- > 2.27.0 >
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