diff options
| author | Yong Zhang <yong.zhang0@gmail.com> | 2011-10-16 18:56:45 +0800 |
|---|---|---|
| committer | Clark Williams <williams@redhat.com> | 2012-02-15 10:32:45 -0600 |
| commit | c44c33388750f5d2486999ea6447f18b39bfacc5 (patch) | |
| tree | bfcb8808dbaf3a5e625f97df0b32f711180b98a9 | |
| parent | 83dee06d29f75a966fead454b98a5bc921d84569 (diff) | |
printk: Don't call printk_tick in printk_needs_cpu() on RT
printk_tick() can't be called in atomic context when RT is enabled,
otherwise below warning will show:
[ 117.597095] BUG: sleeping function called from invalid context at kernel/rtmutex.c:645
[ 117.597102] in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: kworker/0:0
[ 117.597111] Pid: 0, comm: kworker/0:0 Not tainted 3.0.6-rt17-00284-gb76d419-dirty #7
[ 117.597116] Call Trace:
[ 117.597131] [<c06e3b61>] ? printk+0x1d/0x24
[ 117.597142] [<c01390b6>] __might_sleep+0xe6/0x110
[ 117.597151] [<c06e634c>] rt_spin_lock+0x1c/0x30
[ 117.597158] [<c0142f26>] __wake_up+0x26/0x60
[ 117.597166] [<c014c78e>] printk_tick+0x3e/0x40
[ 117.597173] [<c014c7b4>] printk_needs_cpu+0x24/0x30
[ 117.597181] [<c017ecc8>] tick_nohz_stop_sched_tick+0x2e8/0x410
[ 117.597191] [<c017305a>] ? sched_clock_idle_wakeup_event+0x1a/0x20
[ 117.597201] [<c010182a>] cpu_idle+0x4a/0xb0
[ 117.597209] [<c06e0b97>] start_secondary+0xd3/0xd7
Now this is a really rare case and it's very unlikely that we starve
an logbuf waiter that way.
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Link: http://lkml.kernel.org/r/1318762607-2261-4-git-send-email-yong.zhang0@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | kernel/printk.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/printk.c b/kernel/printk.c index 1f0662691664..2b95bc06e7c8 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -1274,8 +1274,8 @@ void printk_tick(void) int printk_needs_cpu(int cpu) { - if (cpu_is_offline(cpu)) - printk_tick(); + if (unlikely(cpu_is_offline(cpu))) + __this_cpu_write(printk_pending, 0); return __this_cpu_read(printk_pending); } |