Commits
Tang Chen committed 301a5cba288
sched: Update sched_domains_numa_masks[][] when new cpus are onlined Once array sched_domains_numa_masks[] []is defined, it is never updated. When a new cpu on a new node is onlined, the coincident member in sched_domains_numa_masks[][] is not initialized, and all the masks are 0. As a result, the build_overlap_sched_groups() will initialize a NULL sched_group for the new cpu on the new node, which will lead to kernel panic: [ 3189.403280] Call Trace: [ 3189.403286] [<ffffffff8106c36f>] warn_slowpath_common+0x7f/0xc0 [ 3189.403289] [<ffffffff8106c3ca>] warn_slowpath_null+0x1a/0x20 [ 3189.403292] [<ffffffff810b1d57>] build_sched_domains+0x467/0x470 [ 3189.403296] [<ffffffff810b2067>] partition_sched_domains+0x307/0x510 [ 3189.403299] [<ffffffff810b1ea2>] ? partition_sched_domains+0x142/0x510 [ 3189.403305] [<ffffffff810fcc93>] cpuset_update_active_cpus+0x83/0x90 [ 3189.403308] [<ffffffff810b22a8>] cpuset_cpu_active+0x38/0x70 [ 3189.403316] [<ffffffff81674b87>] notifier_call_chain+0x67/0x150 [ 3189.403320] [<ffffffff81664647>] ? native_cpu_up+0x18a/0x1b5 [ 3189.403328] [<ffffffff810a044e>] __raw_notifier_call_chain+0xe/0x10 [ 3189.403333] [<ffffffff81070470>] __cpu_notify+0x20/0x40 [ 3189.403337] [<ffffffff8166663e>] _cpu_up+0xe9/0x131 [ 3189.403340] [<ffffffff81666761>] cpu_up+0xdb/0xee [ 3189.403348] [<ffffffff8165667c>] store_online+0x9c/0xd0 [ 3189.403355] [<ffffffff81437640>] dev_attr_store+0x20/0x30 [ 3189.403361] [<ffffffff8124aa63>] sysfs_write_file+0xa3/0x100 [ 3189.403368] [<ffffffff811ccbe0>] vfs_write+0xd0/0x1a0 [ 3189.403371] [<ffffffff811ccdb4>] sys_write+0x54/0xa0 [ 3189.403375] [<ffffffff81679c69>] system_call_fastpath+0x16/0x1b [ 3189.403377] ---[ end trace 1e6cf85d0859c941 ]--- [ 3189.403398] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 This patch registers a new notifier for cpu hotplug notify chain, and updates sched_domains_numa_masks every time a new cpu is onlined or offlined. Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> [ fixed compile warning ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1348578751-16904-3-git-send-email-tangchen@cn.fujitsu.com Signed-off-by: Ingo Molnar <mingo@kernel.org>