Messages in this thread | | | Date | Sat, 14 Jul 2012 12:44:41 +0200 | From | Willy Tarreau <> | Subject | Re: PROBLEM: Silent data corruption when using sendfile() |
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On Sat, Jul 14, 2012 at 12:33:24PM +0200, Eric Dumazet wrote: > On Sat, 2012-07-14 at 12:13 +0200, Johannes Truschnigg wrote: > > On Sat, Jul 14, 2012 at 10:31:36AM +0200, Willy Tarreau wrote: > > > > Please Johannes could you try latest kernel tree ? > > > > > > It would be useful, especially given the amount of changes you performed > > > in this area in latest version, it could be very possible that this new > > > bug got fixed as a side effect ! > > > > I upgraded to 3.4.4 (identical config as the 3.4.0 build I've been running) > > and what can I say - the problem really seems to have disappeared. I performed > > about 3700 iterations of my previos tests over the night, and the data always > > turned out to be OK, not a single byte turned out kaput! > > > > I wish I would have tested that earlier, and spared you the noise... well, > > maybe someone who runs into a similar problem in the future will have this > > discovery save her/him some time and headaches and make her/him just upgrade > > kernels :) > > > > Thanks a lot for your polite and quick responses! > > > > Nice to hear. Now we should make sure we have all needed fixes for prior > stable kernels as well ! > > Still trying to understand the issue, since I thought I only did > optimizations, not bug fixes. So maybe real bug is still there but its > probability of occurrence lowered enough to not hit your workload.
Please note that Johannes tested 3.4.4 while your changes are in 3.5-rc.
I'm wondering whether this patch merged into 3.4.2 one has an impact on sendfile :
commit b642cb6a143da812f188307c2661c0357776a9d0 Author: Konstantin Khlebnikov <khlebnikov@openvz.org> Date: Tue Jun 5 21:36:33 2012 +0400
radix-tree: fix contiguous iterator
commit fffaee365fded09f9ebf2db19066065fa54323c3 upstream.
This patch fixes bug in macro radix_tree_for_each_contig().
If radix_tree_next_slot() sees NULL in next slot it returns NULL, but following radix_tree_next_chunk() switches iterating into next chunk. As result iterating becomes non-contiguous and breaks vfs "splice" and all its users.
Willy
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