Messages in this thread | | | Date | Mon, 11 Jun 2012 10:36:45 +0200 | From | Roland Stigge <> | Subject | Re: [PATCH 1/3] net: lpc_eth: Replace WARN() trace with simple pr_warn() |
| |
Hi Dave and Eric,
thanks for your feedback!
On 06/11/2012 10:25 AM, Eric Dumazet wrote: > On Mon, 2012-06-11 at 10:03 +0200, Roland Stigge wrote: >> A WARN() trace indicating a "BUG!" was identified as a "normal" case in the >> xmit function in case all TX descriptors are occupied already. In this case, >> NETDEV_TX_BUSY is returned, nothing buggy at all. >> >> Signed-off-by: Roland Stigge <stigge@antcom.de> >> Tested-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com> >> >> --- >> drivers/net/ethernet/nxp/lpc_eth.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> --- linux-2.6.orig/drivers/net/ethernet/nxp/lpc_eth.c >> +++ linux-2.6/drivers/net/ethernet/nxp/lpc_eth.c >> @@ -1114,7 +1114,7 @@ static int lpc_eth_hard_start_xmit(struc >> buffers */ >> netif_stop_queue(ndev); >> spin_unlock_irq(&pldat->lock); >> - WARN(1, "BUG! TX request when no free TX buffers!\n"); >> + pr_warn("Note: TX request when no free TX buffers.\n"); >> return NETDEV_TX_BUSY; >> } >> > > Entering this path is a bug, don't hide it... > > Please share with us how this bug was identified as a "normal case" ?
I encountered cases where this happened for me on a custom board under heavy load.
I discussed this with Kevin Wells, the original driver author. We identified the case of xmit()'s TX request (from .ndo_start_xmit) with full TX driver buffers as valid when ethernet is busy.
But maybe this is wrong. Can you please give me a hint how the net subsystem makes sure that this doesn't happen under normal circumstances?
Thanks in advance!
Roland
| |