Re: PROBLEM: Silent data corruption when using sendfile()
From: Thorsten Kranzkowski <hidden>
Date: 2012-07-14 12:08:41
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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:quoted
On Sat, Jul 14, 2012 at 10:31:36AM +0200, Willy Tarreau wrote:quoted
quoted
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. Hmmm...
Not sure if this is related, but I had a similar data corruption problem: Reading data from filesystem 'normally' (including through nfs) showed corruption at random places, mostly 0xff tuning into 0xfe. Reading with ODIRECT (I used 'dd iflag=direct') was OK. I found my problem to be fixed by fffaee365fded09f9ebf2db19066065fa54323c3 (upstrem) which was backported as b642cb6a143da812f188307c2661c0357776a9d0 (stable, v3.4.1-66-gb642cb6) Bye, Thorsten -- | Thorsten Kranzkowski Internet: dl8bcu@dl8bcu.de | | Mobile: ++49 170 1876134 Snail: Kiebitzstr. 14, 49324 Melle, Germany | | Ampr: dl8bcu@db0lj.#rpl.deu.eu, dl8bcu@marvin.dl8bcu.ampr.org [44.130.8.19] |