On Thu, Mar 7, 2019 at 8:02 PM Nathan Chancellor <natechancel...@gmail.com> wrote: > > When building with -Wsometimes-uninitialized, Clang warns: > > drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c:111:2: error: variable > 'ns' is used uninitialized whenever 'if' condition is false > [-Werror,-Wsometimes-uninitialized] > drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c:111:2: error: variable > 'ns' is used uninitialized whenever '&&' condition is false > [-Werror,-Wsometimes-uninitialized] > > Clang is concerned with the use of stmmac_do_void_callback (which > stmmac_get_systime wraps), as it may fail to initialize these values if > the if condition was ever false (meaning the callback doesn't exist). > It's not wrong because the callback is what initializes ns. While it's > unlikely that the callback is going to disappear at some point and make > that condition false, we can easily avoid this warning by zero > initializing the variable. > > Link: https://github.com/ClangBuiltLinux/linux/issues/384 > Fixes: df103170854e ("net: stmmac: Avoid sometimes uninitialized Clang > warnings")
Was initially confused by the link (thought I caught the 3 previous instances in code review of df103170854e). I see now that I did not report stmmac_ptp.c (only stmmac_main.c) properly. Had I, this could have been bundled up into df103170854e indeed. Sorry. Thanks for circling back and cleaning up this additional instance. Reviewed-by: Nick Desaulniers <ndesaulni...@google.com> > Suggested-by: Nick Desaulniers <ndesaulni...@google.com> > Signed-off-by: Nathan Chancellor <natechancel...@gmail.com> > --- > drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c > b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c > index 2293e21f789f..cc60b3fb0892 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c > @@ -105,7 +105,7 @@ static int stmmac_get_time(struct ptp_clock_info *ptp, > struct timespec64 *ts) > struct stmmac_priv *priv = > container_of(ptp, struct stmmac_priv, ptp_clock_ops); > unsigned long flags; > - u64 ns; > + u64 ns = 0; > > spin_lock_irqsave(&priv->ptp_lock, flags); > stmmac_get_systime(priv, priv->ptpaddr, &ns); > -- > 2.21.0 > -- Thanks, ~Nick Desaulniers
