On 09/30/2013 01:24 PM, Dave Jones wrote: > On Mon, Sep 16, 2013 at 02:40:30PM -0400, Dave Jones wrote: > > On a slow machine (with debugging enabled), upgrading selinux policy may > take > > a considerable amount of time. Long enough that the softlockup detector > > gets triggered. > > > > The backtrace looks like this.. > > > > > BUG: soft lockup - CPU#2 stuck for 23s! [load_policy:19045] > > > Call Trace: > > > [<ffffffff81221ddf>] symcmp+0xf/0x20 > > > [<ffffffff81221c27>] hashtab_search+0x47/0x80 > > > [<ffffffff8122e96c>] mls_convert_context+0xdc/0x1c0 > > > [<ffffffff812294e8>] convert_context+0x378/0x460 > > > [<ffffffff81229170>] ? security_context_to_sid_core+0x240/0x240 > > > [<ffffffff812221b5>] sidtab_map+0x45/0x80 > > > [<ffffffff8122bb9f>] security_load_policy+0x3ff/0x580 > > 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 > [<ffffffff810b1639>] ? is_module_text_address+0x19/0x40 > [<ffffffff8122cefe>] security_load_policy+0x10e/0x580 > [<ffffffff81078878>] ? sched_clock_cpu+0xa8/0x100 > [<ffffffff810786ad>] ? sched_clock_local+0x1d/0x80 > [<ffffffff81078878>] ? sched_clock_cpu+0xa8/0x100 > [<ffffffff810786ad>] ? sched_clock_local+0x1d/0x80 > [<ffffffff81078878>] ? sched_clock_cpu+0xa8/0x100 > [<ffffffff8103098a>] ? __change_page_attr_set_clr+0x82a/0xa50 > [<ffffffff81078878>] ? sched_clock_cpu+0xa8/0x100 > [<ffffffff8153669c>] ? retint_restore_args+0xe/0xe > [<ffffffff810a196d>] ? trace_hardirqs_on_caller+0xfd/0x1c0 > [<ffffffff8127b07e>] ? trace_hardirqs_on_thunk+0x3a/0x3f > [<ffffffff810d2958>] ? rcu_irq_exit+0x68/0xb0 > [<ffffffff8153669c>] ? retint_restore_args+0xe/0xe > [<ffffffff8121ff97>] sel_write_load+0xa7/0x770 > [<ffffffff811394c3>] ? vfs_write+0x1c3/0x200 > [<ffffffff812124de>] ? security_file_permission+0x1e/0xa0 > [<ffffffff811393bb>] vfs_write+0xbb/0x200 > [<ffffffff81158337>] ? fget_light+0x397/0x4b0 > [<ffffffff81139ab7>] SyS_write+0x47/0xa0 > [<ffffffff8153d634>] tracesys+0xdd/0xe2 > > 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. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
