Hi Mike, On 2015/1/21 14:16, Mike Galbraith wrote: > > While creating a set of shielded CPUs, we passed cpuset_cpumask_can_shrink() > an empty cpumask (cur), and dl_bw_of(cpumask_any(cur)) made boom with it. > > [ 514.513841] CPU: 0 PID: 6942 Comm: shield.sh Not tainted 3.19.0-master #19 > [ 514.513841] Hardware name: MEDIONPC MS-7502/MS-7502, BIOS 6.00 PG > 12/26/2007 > [ 514.513841] task: ffff880224552450 ti: ffff8800caab8000 task.ti: > ffff8800caab8000 > [ 514.513841] RIP: 0010:[<ffffffff81073846>] [<ffffffff81073846>] > cpuset_cpumask_can_shrink+0x56/0xb0 > [ 514.513841] RSP: 0018:ffff8800caabbda8 EFLAGS: 00010202 > [ 514.513841] RAX: 0000ffff00000000 RBX: ffff880037ae2ab8 RCX: > 0000000000000000 > [ 514.513841] RDX: 0000000000012900 RSI: 0000000000000000 RDI: > 000000000000000c > [ 514.513841] RBP: ffff8800caabbdc8 R08: ffff880037ae2ab8 R09: > 0000000000000034 > [ 514.513841] R10: 00000077e6fd3d1a R11: ffff88022e9b301c R12: > ffff880223c98ab8 > [ 514.513841] R13: ffff880037ae2a00 R14: 0000000000000004 R15: > ffff8802254b3c60 > [ 514.513841] FS: 00007fdbab533700(0000) GS:ffff88022fc00000(0000) > knlGS:0000000000000000 > [ 514.513841] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 514.513841] CR2: 00007ffff8ab8000 CR3: 00000000bef11000 CR4: > 00000000000007f0 > [ 514.513841] Stack: > [ 514.513841] ffff880223c98ab8 ffffffff81a46c20 ffff880223c98a00 > ffff880037ae2a00 > [ 514.513841] ffff8800caabbdf8 ffffffff810cb82a ffff8800caabbdf8 > ffff880037ae2a00 > [ 514.513841] ffff8800ca9e5240 0000000000000000 ffff8800caabbe48 > ffffffff810cc877 > [ 514.513841] Call Trace: > [ 514.513841] [<ffffffff810cb82a>] validate_change+0x18a/0x200 > [ 514.513841] [<ffffffff810cc877>] cpuset_write_resmask+0x3b7/0x720 > [ 514.513841] [<ffffffff810c4d58>] cgroup_file_write+0x38/0x100 > [ 514.513841] [<ffffffff811d953a>] kernfs_fop_write+0x12a/0x180 > [ 514.513841] [<ffffffff8116e1a3>] vfs_write+0xb3/0x1d0 > [ 514.513841] [<ffffffff8116ed06>] SyS_write+0x46/0xb0 > [ 514.513841] [<ffffffff8159ced6>] system_call_fastpath+0x16/0x1b > > Signed-off-by: Mike Galbraith <umgwanakikb...@gmail.com> > > --- > kernel/cpuset.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- a/kernel/cpuset.c > +++ b/kernel/cpuset.c > @@ -511,7 +511,7 @@ static int validate_change(struct cpuset > * tasks. > */ > ret = -EBUSY; > - if (is_cpu_exclusive(cur) && > + if (is_cpu_exclusive(cur) && !cpumask_empty(cur->cpus_allowed) && > !cpuset_cpumask_can_shrink(cur->cpus_allowed, > trial->cpus_allowed)) > goto out; >
We should instead fix cpuset_cpumask_can_shrink() to check if the return value of cpumask_any() >= nr_cpu_ids. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
