From 80bfeeb9dd6b54ac108c884c792f0fc7d4912bee Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Mon, 31 Jul 2017 16:48:29 -0700 Subject: PCI: hv: Do not sleep in compose_msi_msg() The setup of MSI with Hyper-V host was sleeping with locks held. This error is reported when doing SR-IOV hotplug with kernel built with lockdep: BUG: sleeping function called from invalid context at kernel/sched/completion.c:93 in_atomic(): 1, irqs_disabled(): 1, pid: 1405, name: ip 3 locks held by ip/1405: #0: (rtnl_mutex){+.+.+.}, at: [] rtnetlink_rcv+0x1b/0x40 #1: (&desc->request_mutex){+.+...}, at: [] __setup_irq+0xb3/0x720 #2: (&irq_desc_lock_class){-.-...}, at: [] __setup_irq+0xe5/0x720 irq event stamp: 3476 hardirqs last enabled at (3475): [] get_page_from_freelist+0x225/0xc90 hardirqs last disabled at (3476): [] _raw_spin_lock_irqsave+0x27/0x90 softirqs last enabled at (2446): [] ixgbevf_configure+0x380/0x7c0 [ixgbevf] softirqs last disabled at (2444): [] ixgbevf_configure+0x35d/0x7c0 [ixgbevf] The workaround is to poll for host response instead of blocking on completion. Signed-off-by: Stephen Hemminger Signed-off-by: Bjorn Helgaas --- drivers/pci/host/pci-hyperv.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'drivers/pci') diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c index 415dcc69a502..334c9a7b8991 100644 --- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -50,6 +50,7 @@ #include #include #include +#include #include #include #include @@ -1159,7 +1160,12 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) goto free_int_desc; } - wait_for_completion(&comp.comp_pkt.host_event); + /* + * Since this function is called with IRQ locks held, can't + * do normal wait for completion; instead poll. + */ + while (!try_wait_for_completion(&comp.comp_pkt.host_event)) + udelay(100); if (comp.comp_pkt.completion_status < 0) { dev_err(&hbus->hdev->device, -- cgit v1.2.3