Re: linux-next 20141216 BUG: sleeping function called from invalid context at mm/slab.c:2849

On Thu, 2014-12-18 at 12:46 -0500, Richard Guy Briggs wrote: > On 14/12/18, Eric Paris wrote: > > On Thu, 2014-12-18 at 11:45 -0500, Valdis.Kletnieks(a)vt.edu wrote: > > > On Tue, 16 Dec 2014 20:09:54 -0500, Valdis Kletnieks said: > > > > Spotted these two while booting single-user on 20141216. 20141208 > > > > doesn't throw these, so it's something in the last week or so.. > > > > > > Gaah! Turns out that 20141208 *is* susceptible - it had been booting > > > just fine for several days, but it went around the bend, apparently due > > > to a userspace or initrd change. > > > > $5 says you updated systemd? > > > > Richard? > > Ok, so if you are correct, then either we justify dropping the lock (I > assume the one commone to both BUG reports [sig->cred_guard_mutex] ), > or we make yet another queue were were hoping to avoid... > > It would also be good to narrow it down to a rule that triggers this. I thought the first message was enough to find the problem, but: static void kauditd_send_multicast_skb(struct sk_buff *skb) { ... nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL); ... } Since kauditd_send_multicast_skb() gets called in audit_log_end(), which can come from any context (aka even a sleeping context) you can't use GFP_KERNEL. The audit_buffer know what context it should use. So pass that down and use that.

-Eric > > > egrep 'BUG|Linux vers' from my syslog: > > > > > > Dec 9 12:19:53 turing-police kernel: [ 0.000000] Linux version 3.18.0-next-20141208 (source(a)turing-police.cc.vt.edu) (gcc version 4.9.2 20141101 (Red Hat 4.9.2-1) (GCC) ) #27 SMP PREEMPT Mon Dec 8 22:20:07 EST 2014 > ... > > > Dec 12 19:42:30 turing-police kernel: [ 0.000000] Linux version 3.18.0-next-20141208 (source(a)turing-police.cc.vt.edu) (gcc version 4.9.2 20141101 (Red Hat 4.9.2-1) (GCC) ) #27 SMP PREEMPT Mon Dec 8 22:20:07 EST 2014 > > > Dec 12 20:00:39 turing-police kernel: [ 1109.635328] BUG: sleeping function called from invalid context at mm/slab.c:2849 > ... > > > Dec 12 20:42:47 turing-police kernel: [ 3633.863552] BUG: sleeping function called from invalid context at mm/slab.c:2849 > > > Dec 12 20:51:33 turing-police kernel: [ 0.000000] Linux version 3.18.0-next-20141208 (source(a)turing-police.cc.vt.edu) (gcc version 4.9.2 20141101 (Red Hat 4.9.2-1) (GCC) ) #27 SMP PREEMPT Mon Dec 8 22:20:07 EST 2014 > > > Dec 12 21:51:04 turing-police kernel: [ 3587.132867] BUG: sleeping function called from invalid context at mm/slab.c:2849 > ... > > > I need to figure out what changed around 7:30PM on the 12th. > > - RGB