Date: Fri, 06 Aug 2004 16:35:36 -0700 From: Nate Lawson <nate@root.org> To: =?ISO-8859-1?Q?S=F8ren_Schmidt?= <sos@DeepCore.dk> Cc: Radek Kozlowski <radek@raadradd.com> Subject: Re: Panic on boot with today's CURRENT, ata related Message-ID: <411415C8.4070600@root.org> In-Reply-To: <41140722.10807@DeepCore.dk> References: <4113EB2A.7060401@root.org> <41140722.10807@DeepCore.dk>
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Søren Schmidt wrote: > Nate Lawson wrote: > >> I took a quick look at this ATA panic. The exact same one occurs for >> Ceri. A quick dissassemble shows that the testb is the check for the >> DMA flag at the very end of ata_generic_transaction(). The bug >> appears to be that this may be a PIO request (since the DMA check is >> outside the switch() statement). The fix is to make sure it's a DMA >> request before dereferencing an element of the DMA struct. Try the >> attached patch. > > No, the fix is to make sure there is a valid ch->dma pointer, the below > is the correct fix. > > --- ata-lowlevel.c 5 Aug 2004 21:13:41 -0000 1.41 > +++ ata-lowlevel.c 6 Aug 2004 22:31:16 -0000 > @@ -295,7 +295,7 @@ > } > > /* request finish here */ > - if (ch->dma->flags & ATA_DMA_LOADED) > + if (ch->dma && ch->dma->flags & ATA_DMA_LOADED) > ch->dma->unload(ch); > return ATA_OP_FINISHED; > } Thanks. Under what circumstances is a request generated with ATA_R_DMA set in the flags but where the channel's dma struct has not been allocated? -Nate
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