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With CONFIG_PROVE_LOCKING=y in the latest mainline, or old kernels that don't have commit f71b74bca637 ("irq/softirqs: Use lockdep to assert IRQs are disabled/enabled"), it turns out can we trigger a warning at the beginning of __local_bh_enable_ip(), because the upper layer irq code can call hv_compose_msi_msg() with local irqs disabled. Let's fix the warning by switching to local_irq_save()/restore(). This is not an issue because hv_pci_onchannelcallback() is not slow, and it not a hot path. Fixes: de0aa7b2f97d ("PCI: hv: Fix 2 hang issues in hv_compose_msi_msg()") Signed-off-by: Dexuan Cui Cc: Cc: Stephen Hemminger Cc: K. Y. Srinivasan Reviewed-by: Haiyang Zhang --- A trimmed version of the warning is: IRQs not enabled as expected WARNING: CPU: 0 PID: 408 at kernel/softirq.c:162 __local_bh_enable_ip+0xb0/0xe0 Call Trace: hv_compose_msi_msg+0x209/0x462 [pci_hyperv] irq_chip_compose_msi_msg+0x41/0x50 msi_domain_activate+0x1a/0x40 __irq_domain_activate_irq+0x59/0x90 irq_domain_activate_irq+0x25/0x40 __setup_irq+0x3ec/0x730 request_threaded_irq+0xfa/0x1a0 mlx4_init_eq_table+0x3c3/0x5f0 [mlx4_core] mlx4_setup_hca+0x1db/0x750 [mlx4_core] mlx4_load_one+0xad2/0x13b0 [mlx4_core] mlx4_init_one+0x578/0x710 [mlx4_core] local_pci_probe+0x1e/0x50 work_for_cpu_fn+0x10/0x20 process_one_work+0x1d4/0x5a0 worker_thread+0x1cb/0x3d0 kthread+0xf5/0x130 drivers/pci/host/pci-hyperv.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c index 50cdefe..ad6a64d 100644 --- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -1051,6 +1051,7 @@ static u32 hv_compose_msi_req_v2( */ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) { + unsigned long flags; struct irq_cfg *cfg = irqd_cfg(data); struct hv_pcibus_device *hbus; struct hv_pci_dev *hpdev; @@ -1148,14 +1149,14 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) * the channel callback directly when channel->target_cpu is * the current CPU. When the higher level interrupt code * calls us with interrupt enabled, let's add the - * local_bh_disable()/enable() to avoid race. + * local_irq_save()/restore() to avoid race. */ - local_bh_disable(); + local_irq_save(flags); if (hbus->hdev->channel->target_cpu == smp_processor_id()) hv_pci_onchannelcallback(hbus); - local_bh_enable(); + local_irq_restore(flags); if (hpdev->state == hv_pcichild_ejecting) { dev_err_once(&hbus->hdev->device,