lkml.org 
[lkml]   [2019]   [Apr]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] smp: Do not warn if smp_call_function_single() is doing a self call.
Date
If smp_call_function_single() is calling the function for itself, it's safe
to run with irqs_disabled() == true.

I hit the warning because I'm in the below path in the .suspend callback of
a "syscore_ops" to support hibernation for a VM running on Hyper-V:

hv_synic_cleanup() ->
clockevents_unbind_device() ->
clockevents_unbind() ->
smp_call_function_single().

When the .suspend callback runs, only CPU0 is online and irqs_disabled() is
true.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
kernel/smp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index f4cf1b0bb3b8..4fdf6a378def 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -288,7 +288,7 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
* can't happen.
*/
WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
- && !oops_in_progress);
+ && cpu != smp_processor_id() && !oops_in_progress);

csd = &csd_stack;
if (!wait) {
--
2.19.1
\
 
 \ /
  Last update: 2019-04-13 01:54    [W:0.061 / U:4.308 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site