diff options
| author | Paul E. McKenney <paulmck@kernel.org> | 2023-03-20 17:55:16 -0700 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2023-03-24 11:01:26 +0100 |
| commit | 203e435844734cfa503cd1755f35db2514db5cca (patch) | |
| tree | fb35c65fa293455227352868a4e562bf96e1ffa0 | |
| parent | 6366d062e7f97499409979f23f4107a6c45edb04 (diff) | |
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@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20230321005516.50558-4-paulmck@kernel.org
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 13 | ||||
| -rw-r--r-- | 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 b15198a85acb..5f2ec4b0f927 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 7a85bcddd9dc..298ba7570621 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; } |