Messages in this thread Patch in this message | | | Date | Mon, 30 Sep 2013 17:13:42 -0400 | From | Dave Jones <> | Subject | Re: [PATCH] conditionally reschedule while loading selinux policy. |
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On Mon, Sep 30, 2013 at 01:37:53PM -0400, Stephen Smalley wrote:
> > With that patch applied, the problem seems to have moved elsewhere.. > > > > BUG: soft lockup - CPU#3 stuck for 22s! [load_policy:8119] > > irq event stamp: 1590886 > > hardirqs last enabled at (1590885): [<ffffffff8152c3dd>] __slab_alloc.constprop.78+0x4c0/0x4d7 > > hardirqs last disabled at (1590886): [<ffffffff8153e06a>] apic_timer_interrupt+0x6a/0x80 > > softirqs last enabled at (1590336): [<ffffffff810480d9>] __do_softirq+0x169/0x200 > > softirqs last disabled at (1590331): [<ffffffff8104839d>] irq_exit+0x11d/0x140 > > RIP: 0010:[<ffffffff81223182>] [<ffffffff81223182>] hashtab_insert+0x62/0x110 > > > > Call Trace: > > [<ffffffff812283b5>] policydb_read+0xc25/0x1200 > ... > > We're holding a bunch of locks here, so we can't just cond_resched. Thoughts ? > > Sorry, what locks are we holding there? You ought to be able to do a > cond_resched() anywhere during policydb_read() AFAIK; it is loading the > policy into a new structure that isn't being accessed by anything else > yet and the policy_rwlock is only held by security_load_policy after > calling policydb_read and only to switch it into place as the active > policydb.
Hmm, I thought I had tried this already, and got a lot of spew, but it turns out for some reason I had previously patched hashtab_search instead.
I'll try running with this for a while..
Dave
diff --git a/security/selinux/ss/hashtab.c b/security/selinux/ss/hashtab.c index 933e735..2cc4961 100644 --- a/security/selinux/ss/hashtab.c +++ b/security/selinux/ss/hashtab.c @@ -6,6 +6,7 @@ #include <linux/kernel.h> #include <linux/slab.h> #include <linux/errno.h> +#include <linux/sched.h> #include "hashtab.h" struct hashtab *hashtab_create(u32 (*hash_value)(struct hashtab *h, const void *key), @@ -40,6 +41,8 @@ int hashtab_insert(struct hashtab *h, void *key, void *datum) u32 hvalue; struct hashtab_node *prev, *cur, *newnode; + cond_resched(); + if (!h || h->nel == HASHTAB_MAX_NODES) return -EINVAL;
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