luck/tmp_suning_uos_patched
1
0
Fork 1
Code Issues Pull Requests Packages Projects Releases Wiki Activity

sched: Fix KVM and ia64 boot crash due to sched_groups circular linked list assumption

Browse Source 
If we have one cpu that failed to boot and boot cpu gave up on
waiting for it and then another cpu is being booted, kernel
might crash with following OOPS:

   BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
   IP: [<ffffffff812c3630>] __bitmap_weight+0x30/0x80
   Call Trace:
       [<ffffffff8108b9b6>] build_sched_domains+0x7b6/0xa50

The crash happens in init_sched_groups_power() that expects
sched_groups to be circular linked list. However it is not
always true, since sched_groups preallocated in __sdt_alloc are
initialized in build_sched_groups and it may exit early

        if (cpu != cpumask_first(sched_domain_span(sd)))
                return 0;

without initializing sd->groups->next field.

Fix bug by initializing next field right after sched_group was
allocated.

Also-Reported-by: Jiang Liu <liuj97@gmail.com>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Cc: a.p.zijlstra@chello.nl
Cc: pjt@google.com
Cc: seto.hidetoshi@jp.fujitsu.com
Link: http://lkml.kernel.org/r/1336559908-32533-1-git-send-email-imammedo@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Igor Mammedov 2012-05-09 12:38:28 +02:00 committed by Ingo Molnar
parent febb72a6e4
commit 30b4e9eb78
1 changed files with 2 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/sched/core.c
View File

@ -6382,6 +6382,8 @@ static int __sdt_alloc(const struct cpumask *cpu_map)
if (!sg)
return -ENOMEM;
sg->next = sg;
*per_cpu_ptr(sdd->sg, j) = sg;
sgp = kzalloc_node(sizeof(struct sched_group_power),