Return-path: Received: from mms2.broadcom.com ([216.31.210.18]:4361 "EHLO mms2.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932225Ab3GBIra (ORCPT ); Tue, 2 Jul 2013 04:47:30 -0400 Message-ID: <51D29391.4080000@broadcom.com> (sfid-20130702_104741_410043_3816969B) Date: Tue, 2 Jul 2013 10:47:13 +0200 From: "Arend van Spriel" MIME-Version: 1.0 To: "Larry Finger" cc: linville@tuxdriver.com, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, Stable , "Brett Rudley" , "Franky (Zhenhui) Lin" , "Hante Meuleman" , brcm80211-dev-list@broadcom.com, "Neil Horman" Subject: Re: [PATCH] brcmsmac: Fix WARNING caused by lack of calls to dma_mapping_error() References: <1372712883-4464-1-git-send-email-Larry.Finger@lwfinger.net> In-Reply-To: <1372712883-4464-1-git-send-email-Larry.Finger@lwfinger.net> Content-Type: text/plain; charset=iso-8859-1; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 07/01/2013 11:08 PM, Larry Finger wrote: > The driver fails to check the results of DMA mapping in twp places, which results > in the following warning: > > [ 28.078515] ------------[ cut here ]------------ > [ 28.078529] WARNING: at lib/dma-debug.c:937 check_unmap+0x47e/0x930() > [ 28.078533] bcma-pci-bridge 0000:0e:00.0: DMA-API: device driver failed to check map error[device address=0x00000000b5d60d6c] [size=1876 bytes] [mapped as > single] > [ 28.078536] Modules linked in: bnep bluetooth vboxpci(O) vboxnetadp(O) vboxnetflt(O) vboxdrv(O) ipv6 b43 brcmsmac rtl8192cu rtl8192c_common rtlwifi mac802 > 11 brcmutil cfg80211 snd_hda_codec_conexant rng_core snd_hda_intel kvm_amd snd_hda_codec ssb kvm mmc_core snd_pcm snd_seq snd_timer snd_seq_device snd k8temp > cordic joydev serio_raw hwmon sr_mod sg pcmcia pcmcia_core soundcore cdrom i2c_nforce2 i2c_core forcedeth bcma snd_page_alloc autofs4 ext4 jbd2 mbcache crc1 > 6 scsi_dh_alua scsi_dh_hp_sw scsi_dh_rdac scsi_dh_emc scsi_dh ata_generic pata_amd > [ 28.078602] CPU: 1 PID: 2570 Comm: NetworkManager Tainted: G O 3.10.0-rc7-wl+ #42 > [ 28.078605] Hardware name: Hewlett-Packard HP Pavilion dv2700 Notebook PC/30D6, BIOS F.27 11/27/2008 > [ 28.078607] 0000000000000009 ffff8800bbb03ad8 ffffffff8144f898 ffff8800bbb03b18 > [ 28.078612] ffffffff8103e1eb 0000000000000002 ffff8800b719f480 ffff8800b7b9c010 > [ 28.078617] ffffffff824204c0 ffffffff81754d57 0000000000000754 ffff8800bbb03b78 > [ 28.078622] Call Trace: > [ 28.078624] [] dump_stack+0x19/0x1b > [ 28.078634] [] warn_slowpath_common+0x6b/0xa0 > [ 28.078638] [] warn_slowpath_fmt+0x41/0x50 > [ 28.078650] [] check_unmap+0x47e/0x930 > [ 28.078655] [] debug_dma_unmap_page+0x5c/0x70 > [ 28.078679] [] dma64_getnextrxp+0x10c/0x190 [brcmsmac] > [ 28.078691] [] dma_rx+0x62/0x240 [brcmsmac] > [ 28.078707] [] brcms_c_dpc+0x211/0x9d0 [brcmsmac] > [ 28.078717] [] ? brcms_dpc+0x27/0xf0 [brcmsmac] > [ 28.078731] [] brcms_dpc+0x47/0xf0 [brcmsmac] > [ 28.078736] [] tasklet_action+0x6c/0xf0 > --snip-- > [ 28.078974] [] SyS_sendmsg+0xd/0x20 > [ 28.078979] [] tracesys+0xdd/0xe2 > [ 28.078982] ---[ end trace 6164d1a08148e9c8 ]--- > [ 28.078984] Mapped at: > [ 28.078985] [] debug_dma_map_page+0x9d/0x150 > [ 28.078989] [] dma_rxfill+0x102/0x3d0 [brcmsmac] > [ 28.079001] [] brcms_c_init+0x87d/0x1100 [brcmsmac] > [ 28.079010] [] brcms_init+0x21/0x30 [brcmsmac] > [ 28.079018] [] brcms_c_up+0x150/0x430 [brcmsmac] > > As the patch adds a new failure mechanism to dma_rxfill(). When I changed the > comment at the start of the routine to add that information, I also polished > the wording. Thanks, Larry I think there a bugzilla issue for this that you might want to reference: https://bugzilla.kernel.org/show_bug.cgi?id=60261 > Signed-off-by: Larry Finger > Cc: Stable > Cc: Brett Rudley > Cc: Arend van Spriel > Cc: Franky (Zhenhui) Lin > Cc: Hante Meuleman > Cc: brcm80211-dev-list@broadcom.com > --- > > drivers/net/wireless/brcm80211/brcmsmac/dma.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/wireless/brcm80211/brcmsmac/dma.c b/drivers/net/wireless/brcm80211/brcmsmac/dma.c > index 1860c57..6260571 100644 > --- a/drivers/net/wireless/brcm80211/brcmsmac/dma.c > +++ b/drivers/net/wireless/brcm80211/brcmsmac/dma.c > @@ -1015,9 +1015,10 @@ static bool dma64_txidle(struct dma_info *di) > > /* > * post receive buffers > - * return false is refill failed completely and ring is empty this will stall > - * the rx dma and user might want to call rxfill again asap. This unlikely > - * happens on memory-rich NIC, but often on memory-constrained dongle > + * return false is refill failed completely or dma mapping failed. The ring Missed some polishing opportunity: return false is refill... -> return false if refill... > + * is empty, which will stall the rx dma and user might want to call rxfill > + * again asap. This is unlikely to happen on a memory-rich NIC, but often on > + * memory-constrained dongle > */ > bool dma_rxfill(struct dma_pub *pub) > { > @@ -1078,6 +1079,8 @@ bool dma_rxfill(struct dma_pub *pub) > > pa = dma_map_single(di->dmadev, p->data, di->rxbufsize, > DMA_FROM_DEVICE); > + if (dma_mapping_error(di->dmadev,pa)) > + return false; > > /* save the free packet pointer */ > di->rxp[rxout] = p; > @@ -1284,7 +1287,8 @@ static void dma_txenq(struct dma_info *di, struct sk_buff *p) > > /* get physical address of buffer start */ > pa = dma_map_single(di->dmadev, data, len, DMA_TO_DEVICE); > - > + if(dma_mapping_error(di->dmadev, pa)) > + return; I think the caller(s) should be informed or silently free the sk_buff here so we are not leaking it. > /* With a DMA segment list, Descriptor table is filled > * using the segment list instead of looping over > * buffers in multi-chain DMA. Therefore, EOF for SGLIST > Regards, Arend