6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nick Hu <nick.hu@xxxxxxxxxx>
[ Upstream commit 3908ba2e0b2476e2ec13e15967bf6a37e449f2af ]
Sometimes the hotplug cpu stalls at the arch_cpu_idle() for a while after
workqueue_online_cpu(). When cpu stalls at the idle loop, the reschedule
IPI is pending. However the enable bit is not enabled yet so the cpu stalls
at WFI until watchdog timeout. Therefore enable the IPI before the
workqueue_online_cpu() to fix the issue.
Fixes: 63c5484e7495 ("workqueue: Add multiple affinity scopes and interface to select them")
Signed-off-by: Nick Hu <nick.hu@xxxxxxxxxx>
Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240717031714.1946036-1-nick.hu@xxxxxxxxxx
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/riscv/kernel/sbi-ipi.c | 2 +-
include/linux/cpuhotplug.h | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/kernel/sbi-ipi.c b/arch/riscv/kernel/sbi-ipi.c
index 1026e22955ccc..0cc5559c08d8f 100644
--- a/arch/riscv/kernel/sbi-ipi.c
+++ b/arch/riscv/kernel/sbi-ipi.c
@@ -71,7 +71,7 @@ void __init sbi_ipi_init(void)
* the masking/unmasking of virtual IPIs is done
* via generic IPI-Mux
*/
- cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
+ cpuhp_setup_state(CPUHP_AP_IRQ_RISCV_SBI_IPI_STARTING,
"irqchip/sbi-ipi:starting",
sbi_ipi_starting_cpu, NULL);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 7a5785f405b62..0a8fd4a3d04c9 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -147,6 +147,7 @@ enum cpuhp_state {
CPUHP_AP_IRQ_LOONGARCH_STARTING,
CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
CPUHP_AP_IRQ_RISCV_IMSIC_STARTING,
+ CPUHP_AP_IRQ_RISCV_SBI_IPI_STARTING,
CPUHP_AP_ARM_MVEBU_COHERENCY,
CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING,
CPUHP_AP_PERF_X86_STARTING,
--
2.43.0
