The following commit has been merged into the smp/core branch of tip:
Commit-ID: 203e435844734cfa503cd1755f35db2514db5cca
Gitweb: https://git.kernel.org/tip/203e435844734cfa503cd1755f35db2514db5cca
Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
AuthorDate: Mon, 20 Mar 2023 17:55:16 -07:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Fri, 24 Mar 2023 11:01:26 +01:00
kernel/smp: Make csdlock_debug= resettable
It is currently possible to set the csdlock_debug_enabled static
branch, but not to reset it. This is an issue when several different
entities supply kernel boot parameters and also for kernels built with
CONFIG_CSD_LOCK_WAIT_DEBUG_DEFAULT=y.
Therefore, make the csdlock_debug=0 kernel boot parameter turn off
debugging. Last one wins!
Reported-by: Jes Sorensen <Jes.Sorensen@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Juergen Gross <jgross@xxxxxxxx>
Link: https://lore.kernel.org/r/20230321005516.50558-4-paulmck@xxxxxxxxxx
---
Documentation/admin-guide/kernel-parameters.txt | 13 +++++++------
kernel/smp.c | 11 ++++++++---
2 files changed, 15 insertions(+), 9 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index b15198a..5f2ec4b 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -889,12 +889,13 @@
cs89x0_media= [HW,NET]
Format: { rj45 | aui | bnc }
- csdlock_debug= [KNL] Enable debug add-ons of cross-CPU function call
- handling. When switched on, additional debug data is
- printed to the console in case a hanging CPU is
- detected, and that CPU is pinged again in order to try
- to resolve the hang situation. The default value of
- this option depends on the CSD_LOCK_WAIT_DEBUG_DEFAULT
+ csdlock_debug= [KNL] Enable or disable debug add-ons of cross-CPU
+ function call handling. When switched on,
+ additional debug data is printed to the console
+ in case a hanging CPU is detected, and that
+ CPU is pinged again in order to try to resolve
+ the hang situation. The default value of this
+ option depends on the CSD_LOCK_WAIT_DEBUG_DEFAULT
Kconfig option.
dasd= [HW,NET]
diff --git a/kernel/smp.c b/kernel/smp.c
index 7a85bcd..298ba75 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -116,11 +116,16 @@ static DEFINE_STATIC_KEY_MAYBE(CONFIG_CSD_LOCK_WAIT_DEBUG_DEFAULT, csdlock_debug
*/
static int __init csdlock_debug(char *str)
{
+ int ret;
unsigned int val = 0;
- get_option(&str, &val);
- if (val)
- static_branch_enable(&csdlock_debug_enabled);
+ ret = get_option(&str, &val);
+ if (ret) {
+ if (val)
+ static_branch_enable(&csdlock_debug_enabled);
+ else
+ static_branch_disable(&csdlock_debug_enabled);
+ }
return 1;
}
|