4.19-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 1f5d861f7fefa971b2c6e766f77932c86419a319 ]
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") Suggested-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Nathan Chancellor natechancellor@gmail.com Reviewed-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- 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);