[tip:sched/urgent] sched: Fix boot crash by zalloc()ing most of the cpu masks

From: tip-bot for Rusty Russell
Date: Mon Nov 02 2009 - 11:17:28 EST

Commit-ID: 49557e620339cb134127b5bfbcfecc06b77d0232
Gitweb: http://git.kernel.org/tip/49557e620339cb134127b5bfbcfecc06b77d0232
Author: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
AuthorDate: Mon, 2 Nov 2009 20:37:20 +1030
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Mon, 2 Nov 2009 15:48:54 +0100

sched: Fix boot crash by zalloc()ing most of the cpu masks

I got a boot crash when forcing cpumasks offstack on 32 bit,
because find_new_ilb() returned 3 on my UP system (nohz.cpu_mask
wasn't zeroed).

AFAICT the others need to be zeroed too: only
nohz.ilb_grp_nohz_mask is initialized before use.

Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
LKML-Reference: <200911022037.21282.rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
kernel/sched.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index cae6700..bf21adb 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -9535,13 +9535,13 @@ void __init sched_init(void)
current->sched_class = &fair_sched_class;

/* Allocate the nohz_cpu_mask if CONFIG_CPUMASK_OFFSTACK */
- alloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT);
+ zalloc_cpumask_var(&nohz_cpu_mask, GFP_NOWAIT);
- alloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
+ zalloc_cpumask_var(&nohz.cpu_mask, GFP_NOWAIT);
alloc_cpumask_var(&nohz.ilb_grp_nohz_mask, GFP_NOWAIT);
- alloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
+ zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
#endif /* SMP */

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