Re: kauditd hold queue overflow in 4.11

On Saturday, September 9, 2017 6:02:02 AM EDT Laurent Bigonville wrote: > Le 11/07/17 à 00:23, Paul Moore a écrit : >> On Mon, Jul 10, 2017 at 4:01 PM, Laurent Bigonville <bigon(a)debian.org&gt; wrote: >>> Le 10/07/17 à 18:00, Paul Moore a écrit : >>>> On Mon, Jul 10, 2017 at 10:59 AM, Laurent Bigonville <bigon(a)debian.org&gt; >>>> >>>> wrote: >>>>> Hi, >>>>> >>>>> With 4.11.6 (that has been uploaded in debian unstable) I get a lot of >>>>> messages in dmesg like >>>>> >>>>> [100052.120468] audit: audit_lost=66041 audit_rate_limit=0 >>>>> audit_backlog_limit=8192 >>>>> [100052.120470] audit: kauditd hold queue overflow >>>>> >>>>> And it also seems that the messages are not stored in auditd logs >>>>> anymore. >>>>> >>>>> https://git.kernel.org/linus/264d509637d95f9404e52ced5003ad352e0f6a26 >>>>> seems >>>>> to be included in this release >>>>> >>>>> An idea? >>>> 7 >>>> I'm going to assume that your backlog limit is set to a sane value for >>>> your system's configuration, so that leaves me with two commits that >>>> may be of interest: >>>> >>>> * 1df30f8264b8 ("audit: fix the RCU locking for the auditd_connection >>>> structure") >>>> >>>> This was a manual backport of a v4.12 patch to v4.11, looking now, I >>>> see it should be in +v4.11.5 so that probably isn't your problem ... >>>> >>>> * c81be52a3ac0 ("audit: fix a race condition with the auditd tracking >>>> code") >>>> >>>> This patch is relatively new and was just sent up to Linus during the >>>> next merge window; it's a race condition fix so reproducing it can be >>>> tricky, although it may be easily reproducible on your system at the >>>> moment (luck you!). If you aren't in a position to apply the patch, >>>> the workaround is rather simple: restart auditd. >>>> >>>> If none of the above works, let me know, but I strongly suspect you're >>>> tripping over the race condition fixed in that last patch. >>> I didn't test the patch yet, but I restarted the auditd daemon 2 times >>> and >>> after that the queue has been flushed and I got all the message since >>> this >>> noon in the audit logs. >> That sounds right; I'm guessing the patch above should be a more permanent >> fix. > The patch should be applied in 4.13-rc7 right? > > It seems to fix the main issue (all the audit messages being logged in > dmesg) but I can still see from time to time the following message: > > [ 14.747565] audit: audit_lost=59 audit_rate_limit=0 > audit_backlog_limit=64 [ 14.747566] audit: kauditd hold queue overflow That is a very low backlog_limit. Is this during boot?