On Wed, 2009-12-02 at 11:18 -0800, Cahill, Ben M wrote: > > >-----Original Message----- > >From: Zhu Yi [mailto:yi.zhu@xxxxxxxxx] > >Sent: Wednesday, December 02, 2009 12:43 AM > >To: Maxim Levitsky > >Cc: Chatre, Reinette; linux-wireless; iwlwifi maling list > >Subject: Re: [ipw3945-devel] Panic in iwl3945 driver > > > >On Tue, 2009-12-01 at 17:28 +0800, Zhu Yi wrote: > >> On Tue, 2009-12-01 at 06:35 +0800, Maxim Levitsky wrote: > >> > 0x000000000001668e <iwl3945_rx_reply_tx+302>: lea > >0x38(%r8),%rdi > >> > 0x0000000000016692 <iwl3945_rx_reply_tx+306>: lea > >0x4f(%r8),%rax > >> > >> When this happened, from your previous post, r8 is 0x0 and > >rdi is 0x38. > >> Since "info" is %rdi (see below), this means > >> txq->txb[txq->q.read_ptr].skb[0], aka. r8 is 0. > >> > >> > rate_idx = iwl3945_hwrate_to_plcp_idx(tx_resp->rate); > >> > > >> > 0x0000000000016696 <iwl3945_rx_reply_tx+310>: movb > >$0x0,0x9(%rdi) <---------- RIP > >> > 0x000000000001669a <iwl3945_rx_reply_tx+314>: movb > >$0x0,0xc(%rdi) > >> > 0x000000000001669e <iwl3945_rx_reply_tx+318>: movb > >$0x0,0xf(%rdi) > >> > 0x00000000000166a2 <iwl3945_rx_reply_tx+322>: movb > >$0x0,0x12(%rdi) > >> > 0x00000000000166a6 <iwl3945_rx_reply_tx+326>: movb > >$0x0,0x15(%rdi) > >> > >> This equals to below code in > >ieee80211_tx_info_clear_status(). "info" is > >> %rdi, which is 0x38. That matches NULL pointer dereference at 0x41 in > >> your oops header. > >> > >> for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) > >> info->status.rates[i].count = 0; > >> > >> I guess there is a race for txq->q.read_ptr somewhere. > >Haven't checked > >> though. > > > >OK. 3945 updated write_ptr without regard to read_ptr on the Tx path. > >This messes up our TFD on high load. The patch should fix your problem. > > Wow. Could this be happening with other devices as well? > We do check this on other devices. Abhijeet > -- Ben -- > > > > > >Signed-off-by: Zhu Yi <yi.zhu@xxxxxxxxx> > > > >diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c > >b/drivers/net/wireless/iwlwifi/iwl3945-base.c > >index 994db4a..b31b34c 100644 > >--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c > >+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c > >@@ -548,6 +548,9 @@ static int iwl3945_tx_skb(struct iwl_priv > >*priv, struct sk_buff *skb) > > txq = &priv->txq[txq_id]; > > q = &txq->q; > > > >+ if ((iwl_queue_space(q) < q->high_mark)) > >+ goto drop; > >+ > > spin_lock_irqsave(&priv->lock, flags); > > > > idx = get_cmd_index(q, q->write_ptr, 0); > > > > > > > >--------------------------------------------------------------- > >--------------- > >Join us December 9, 2009 for the Red Hat Virtual Experience, > >a free event focused on virtualization and cloud computing. > >Attend in-depth sessions from your desk. Your couch. Anywhere. > >http://p.sf.net/sfu/redhat-sfdev2dev > >_______________________________________________ > >Ipw3945-devel mailing list > >Ipw3945-devel@xxxxxxxxxxxxxxxxxxxxx > >https://lists.sourceforge.net/lists/listinfo/ipw3945-devel > >-- > To unsubscribe from this list: send the line "unsubscribe linux-wireless" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
