Messages in this thread | | | From | Nick Desaulniers <> | Date | Wed, 20 Mar 2019 13:41:03 -0700 | Subject | Re: -Wsometimes-uninitialized Clang warning in drivers/net/ethernet/broadcom/bnxt/bnxt.c |
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+ Broadcom folks from commit c0c050c58d84 ("bnxt_en: New Broadcom ethernet driver."). Looks like Michael wrote and is still maintaining the driver.
On Wed, Mar 20, 2019 at 12:08 PM Nathan Chancellor <natechancellor@gmail.com> wrote: > > On Thu, Mar 07, 2019 at 05:57:35PM -0700, Nathan Chancellor wrote: > > Hi all, > > > > We are trying to get Clang's -Wsometimes-uninitialized turned on for the > > kernel as it can catch some bugs that GCC can't. This warning came up: > > > > drivers/net/ethernet/broadcom/bnxt/bnxt.c:1612:6: warning: variable 'len' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] > > if (rxcmp1->rx_cmp_cfa_code_errors_v2 & RX_CMP_L2_ERRORS) { > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > drivers/net/ethernet/broadcom/bnxt/bnxt.c:1703:19: note: uninitialized use occurs here > > cpr->rx_bytes += len; > > ^~~ > > drivers/net/ethernet/broadcom/bnxt/bnxt.c:1612:2: note: remove the 'if' if its condition is always false > > if (rxcmp1->rx_cmp_cfa_code_errors_v2 & RX_CMP_L2_ERRORS) { > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > drivers/net/ethernet/broadcom/bnxt/bnxt.c:1540:18: note: initialize the variable 'len' to silence this warning > > unsigned int len; > > ^ > > = 0 > > 1 warning generated. > > > > It seems like the logical change to make is this; however, I am not sure > > if this has any other unintended consequences since this is a rather > > dense function. I would much appreciate your input, especially if there > > is a better way to fix it.
I agree that `goto next_rx_no_prod_no_len` appears to be most correct; though I don't understand why this function is a mix of early return codes, vs setting rc then updating *raw_cons. The alternative is probably zero initializing len, but I'm not sure whether *raw_cons should be updated in that case or not. Thanks for bringing this up and the patch. Sorry for the delay in review. Can folks at Broadcom please clarify?
-- Thanks, ~Nick Desaulniers
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