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authorDongli Zhang <dongli.zhang@oracle.com>2021-04-09 07:53:16 +0200
committerThomas Gleixner <tglx@linutronix.de>2021-08-10 18:31:32 +0200
commitebca71a8c96f0af2ba482489ecc64d88979cd825 (patch)
treed125a5ac0533fa2a3a70adad3210598a8b1c8c77 /kernel/cpu.c
parentcpu/hotplug: Use DEVICE_ATTR_*() macro (diff)
downloadlinux-ebca71a8c96f0af2ba482489ecc64d88979cd825.tar.xz
linux-ebca71a8c96f0af2ba482489ecc64d88979cd825.zip
cpu/hotplug: Add debug printks for hotplug callback failures
CPU hotplug callbacks can fail and cause a rollback to the previous state. These failures are silent and therefore hard to debug. Add pr_debug() to the up and down paths which provide information about the error code, the CPU and the failed state. The debug printks can be enabled via kernel command line or sysfs. [ tglx: Adopt to current mainline, massage printk and changelog ] Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Qais Yousef <qais.yousef@arm.com> Link: https://lore.kernel.org/r/20210409055316.1709-1-dongli.zhang@oracle.com
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r--kernel/cpu.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 7ef28e1d5ecd..192e43a87407 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -692,6 +692,10 @@ static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
ret = cpuhp_invoke_callback_range(true, cpu, st, target);
if (ret) {
+ pr_debug("CPU UP failed (%d) CPU %u state %s (%d)\n",
+ ret, cpu, cpuhp_get_step(st->state)->name,
+ st->state);
+
cpuhp_reset_state(st, prev_state);
if (can_rollback_cpu(st))
WARN_ON(cpuhp_invoke_callback_range(false, cpu, st,
@@ -1091,6 +1095,9 @@ static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
ret = cpuhp_invoke_callback_range(false, cpu, st, target);
if (ret) {
+ pr_debug("CPU DOWN failed (%d) CPU %u state %s (%d)\n",
+ ret, cpu, cpuhp_get_step(st->state)->name,
+ st->state);
cpuhp_reset_state(st, prev_state);