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authorhe, bo <bo.he@intel.com>2012-04-25 19:59:21 +0800
committerIngo Molnar <mingo@kernel.org>2012-04-26 12:54:53 +0200
commitfb2cf2c660971bea0ad86a9a5c19ad39eab61344 (patch)
tree75343c1ef32657416dbef2dd5a683391ff8b00c9
parenteb95308ee2a69403909e111837b9068c64cfc349 (diff)
downloadlinux-fb2cf2c660971bea0ad86a9a5c19ad39eab61344.tar.gz
sched: Fix OOPS when build_sched_domains() percpu allocation fails
Under extreme memory used up situations, percpu allocation might fail. We hit it when system goes to suspend-to-ram, causing a kworker panic: EIP: [<c124411a>] build_sched_domains+0x23a/0xad0 Kernel panic - not syncing: Fatal exception Pid: 3026, comm: kworker/u:3 3.0.8-137473-gf42fbef #1 Call Trace: [<c18cc4f2>] panic+0x66/0x16c [...] [<c1244c37>] partition_sched_domains+0x287/0x4b0 [<c12a77be>] cpuset_update_active_cpus+0x1fe/0x210 [<c123712d>] cpuset_cpu_inactive+0x1d/0x30 [...] With this fix applied build_sched_domains() will return -ENOMEM and the suspend attempt fails. Signed-off-by: he, bo <bo.he@intel.com> Reviewed-by: Zhang, Yanmin <yanmin.zhang@intel.com> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: <stable@kernel.org> Link: http://lkml.kernel.org/r/1335355161.5892.17.camel@hebo [ So, we fail to deallocate a CPU because we cannot allocate RAM :-/ I don't like that kind of sad behavior but nevertheless it should not crash under high memory load. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--kernel/sched/core.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 4603b9d8f30..0533a688ce2 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6405,16 +6405,26 @@ static void __sdt_free(const struct cpumask *cpu_map)
struct sd_data *sdd = &tl->data;
for_each_cpu(j, cpu_map) {
- struct sched_domain *sd = *per_cpu_ptr(sdd->sd, j);
- if (sd && (sd->flags & SD_OVERLAP))
- free_sched_groups(sd->groups, 0);
- kfree(*per_cpu_ptr(sdd->sd, j));
- kfree(*per_cpu_ptr(sdd->sg, j));
- kfree(*per_cpu_ptr(sdd->sgp, j));
+ struct sched_domain *sd;
+
+ if (sdd->sd) {
+ sd = *per_cpu_ptr(sdd->sd, j);
+ if (sd && (sd->flags & SD_OVERLAP))
+ free_sched_groups(sd->groups, 0);
+ kfree(*per_cpu_ptr(sdd->sd, j));
+ }
+
+ if (sdd->sg)
+ kfree(*per_cpu_ptr(sdd->sg, j));
+ if (sdd->sgp)
+ kfree(*per_cpu_ptr(sdd->sgp, j));
}
free_percpu(sdd->sd);
+ sdd->sd = NULL;
free_percpu(sdd->sg);
+ sdd->sg = NULL;
free_percpu(sdd->sgp);
+ sdd->sgp = NULL;
}
}