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authorHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>2008-09-10 17:00:19 -0700
committerIngo Molnar <mingo@elte.hu>2008-09-11 09:39:18 +0200
commitec5d498991e87c74730509508b25c3959192b7e7 (patch)
treefb5e9eb769ea7a6468f3c9de3c5d9865ba2d70de
parentbaf25731e54d06eb13dc4eda78c6dc7da4ce84e8 (diff)
downloadlinux-linaro-android-ec5d498991e87c74730509508b25c3959192b7e7.tar.gz
sched: fix deadlock in setting scheduler parameter to zero
Andrei Gusev wrote: > I played witch scheduler settings. After doing something like: > echo -n 1000000 >sched_rt_period_us > > command is locked. I found in kernel.log: > > Sep 11 00:39:34 zaratustra > Sep 11 00:39:34 zaratustra Pid: 4495, comm: bash Tainted: G W > (2.6.26.3 #12) > Sep 11 00:39:34 zaratustra EIP: 0060:[<c0213fc7>] EFLAGS: 00210246 CPU: 0 > Sep 11 00:39:34 zaratustra EIP is at div64_u64+0x57/0x80 > Sep 11 00:39:34 zaratustra EAX: 0000389f EBX: 00000000 ECX: 00000000 > EDX: 00000000 > Sep 11 00:39:34 zaratustra ESI: d9800000 EDI: d9800000 EBP: 0000389f > ESP: ea7a6edc > Sep 11 00:39:34 zaratustra DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068 > Sep 11 00:39:34 zaratustra Process bash (pid: 4495, ti=ea7a6000 > task=ea744000 task.ti=ea7a6000) > Sep 11 00:39:34 zaratustra Stack: 00000000 000003e8 d9800000 0000389f > c0119042 00000000 00000000 00000001 > Sep 11 00:39:34 zaratustra 00000000 00000000 ea7a6f54 00010000 00000000 > c04d2e80 00000001 000e7ef0 > Sep 11 00:39:34 zaratustra c01191a3 00000000 00000000 ea7a6fa0 00000001 > ffffffff c04d2e80 ea5b2480 > Sep 11 00:39:34 zaratustra Call Trace: > Sep 11 00:39:34 zaratustra [<c0119042>] __rt_schedulable+0x52/0x130 > Sep 11 00:39:34 zaratustra [<c01191a3>] sched_rt_handler+0x83/0x120 > Sep 11 00:39:34 zaratustra [<c01a76a6>] proc_sys_call_handler+0xb6/0xd0 > Sep 11 00:39:34 zaratustra [<c01a76c0>] proc_sys_write+0x0/0x20 > Sep 11 00:39:34 zaratustra [<c01a76d9>] proc_sys_write+0x19/0x20 > Sep 11 00:39:34 zaratustra [<c016cc68>] vfs_write+0xa8/0x140 > Sep 11 00:39:34 zaratustra [<c016cdd1>] sys_write+0x41/0x80 > Sep 11 00:39:34 zaratustra [<c0103051>] sysenter_past_esp+0x6a/0x91 > Sep 11 00:39:34 zaratustra ======================= > Sep 11 00:39:34 zaratustra Code: c8 41 0f ad f3 d3 ee f6 c1 20 0f 45 de > 31 f6 0f ad ef d3 ed f6 c1 20 0f 45 fd 0f 45 ee 31 c9 39 eb 89 fe 89 ea > 77 08 89 e8 31 d2 <f7> f3 89 c1 89 f0 8b 7c 24 08 f7 f3 8b 74 24 04 89 > ca 8b 1c 24 > Sep 11 00:39:34 zaratustra EIP: [<c0213fc7>] div64_u64+0x57/0x80 SS:ESP > 0068:ea7a6edc > Sep 11 00:39:34 zaratustra ---[ end trace 4eaa2a86a8e2da22 ]--- fix the boundary condition. sysctl_sched_rt_period=0 makes exception at to_ratio(). Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/sched.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index cc1f81b50b8..98890807375 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8909,6 +8909,9 @@ static int sched_rt_global_constraints(void)
u64 rt_runtime, rt_period;
int ret = 0;
+ if (sysctl_sched_rt_period <= 0)
+ return -EINVAL;
+
rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
rt_runtime = tg->rt_bandwidth.rt_runtime;
@@ -8925,6 +8928,9 @@ static int sched_rt_global_constraints(void)
unsigned long flags;
int i;
+ if (sysctl_sched_rt_period <= 0)
+ return -EINVAL;
+
spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
for_each_possible_cpu(i) {
struct rt_rq *rt_rq = &cpu_rq(i)->rt;