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authorMike Galbraith <umgwanakikbuti@gmail.com>2015-01-28 04:53:55 +0100
committerIngo Molnar <mingo@kernel.org>2015-01-28 15:28:15 +0100
commitbb2bc55a694d45cdeda91b6f28ab2adec28125ef (patch)
tree457cf0682f1acb2dc3fd94a13224e59c7b81a31b /kernel/sched
parent81907478c4311a679849216abf723999184ab984 (diff)
sched: Fix crash if cpuset_cpumask_can_shrink() is passed an empty cpumask
While creating an exclusive cpuset, we passed cpuset_cpumask_can_shrink() an empty cpumask (cur), and dl_bw_of(cpumask_any(cur)) made boom with it: CPU: 0 PID: 6942 Comm: shield.sh Not tainted 3.19.0-master #19 Hardware name: MEDIONPC MS-7502/MS-7502, BIOS 6.00 PG 12/26/2007 task: ffff880224552450 ti: ffff8800caab8000 task.ti: ffff8800caab8000 RIP: 0010:[<ffffffff81073846>] [<ffffffff81073846>] cpuset_cpumask_can_shrink+0x56/0xb0 [...] Call Trace: [<ffffffff810cb82a>] validate_change+0x18a/0x200 [<ffffffff810cc877>] cpuset_write_resmask+0x3b7/0x720 [<ffffffff810c4d58>] cgroup_file_write+0x38/0x100 [<ffffffff811d953a>] kernfs_fop_write+0x12a/0x180 [<ffffffff8116e1a3>] vfs_write+0xb3/0x1d0 [<ffffffff8116ed06>] SyS_write+0x46/0xb0 [<ffffffff8159ced6>] system_call_fastpath+0x16/0x1b Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com> Acked-by: Zefan Li <lizefan@huawei.com> Fixes: f82f80426f7a ("sched/deadline: Ensure that updates to exclusive cpusets don't break AC") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1422417235.5716.5.camel@marge.simpson.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/core.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c0accc00566e..5c86687d22b3 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4642,6 +4642,9 @@ int cpuset_cpumask_can_shrink(const struct cpumask *cur,
struct dl_bw *cur_dl_b;
unsigned long flags;
+ if (!cpumask_weight(cur))
+ return ret;
+
rcu_read_lock_sched();
cur_dl_b = dl_bw_of(cpumask_any(cur));
trial_cpus = cpumask_weight(trial);