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Date: Sun, 11 Jan 2015 01:39:13 +0000 From: Al Viro <viro@...IV.linux.org.uk> To: "Carlos R. Mafra" <crmafra@...il.com> Cc: LKML <linux-kernel@...r.kernel.org>, Hauke Mehrtens <hauke@...ke-m.de>, "John W. Linville" <linville@...driver.com>, netdev@...r.kernel.org Subject: Re: /proc/net/dev regression On Sun, Jan 11, 2015 at 01:33:35AM +0000, Carlos R. Mafra wrote: > I think the problem with wmnet is not that it was expecting the fields > to be aligned because it never had problems before (when definitely more > than 10 megabytes were received, wmnet is crappy but not _that_ crappy). > > I think the problem really was here, > > totalbytes_in = strtoul(&buffer[7], NULL, 10); > > After the patch the device name is 8 characters long and &buffer[7] > overlaps with the name instead of reading the bytes. Before the > patch is was fine because the call to strtoul() seems correct in the > sense that it would read everything until the NULL. So more than 10 > megabytes was still ok. > > So I guess I was wrong when suggesting that the problem was the > alignment. Several lines below there's this: totalpackets_out = strtoul(&buffer[74], NULL, 10); if (totalpackets_out != lastpackets_out) { totalbytes_out = strtoul(&buffer[66], NULL, 10); diffpackets_out += totalpackets_out - lastpackets_out; diffbytes_out += totalbytes_out - lastbytes_out; lastpackets_out = totalpackets_out; lastbytes_out = totalbytes_out; tx = True; } So I'm afraid it *is* that crappy. This function really should use scanf(); note that updateStats_ipchains() in the same file does just that (well, fgets()+sscanf() for fsck knows what reason). And I'd be careful with all those %d, actually - it's not _that_ hard to get more than 4Gb sent. scanf formats really ought to match the kernel-side (seq_)printf one... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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