pci-hyperv: do not sleep in compose_msi_msg
PATCH 1/1 pci-hyperv: 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: [<ffffffff976b10bb>] rtnetlink_rcv+0x1b/0x40
#1: (&desc->request_mutex){+.+...}, at: [<ffffffff970ddd33>] __setup_irq+0xb3/0x720
#2: (&irq_desc_lock_class){-.-...}, at: [<ffffffff970ddd65>] __setup_irq+0xe5/0x720
irq event stamp: 3476
hardirqs last enabled at (3475): [<ffffffff971b3005>] get_page_from_freelist+0x225/0xc90
hardirqs last disabled at (3476): [<ffffffff978024e7>] _raw_spin_lock_irqsave+0x27/0x90
softirqs last enabled at (2446): [<ffffffffc05ef0b0>] ixgbevf_configure+0x380/0x7c0 [ixgbevf]
softirqs last disabled at (2444): [<ffffffffc05ef08d>] ixgbevf_configure+0x35d/0x7c0 [ixgbevf]The workaround is to poll for host response instead of blocking on completion.
Signed-off-by Stephen Hemminger <[email protected]>
--- drivers/pci/host/pci-hyperv.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
drivers/pci/host/pci-hyperv.c +7 -1
@@ -50,6 +50,7 @@#include <linux/kernel.h> #include <linux/module.h> #include <linux/pci.h> +#include <linux/delay.h> #include <linux/semaphore.h> #include <linux/irqdomain.h> #include <asm/irqdomain.h>
@@ -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,
Signature · 1 line
2.11.0
Bjorn Helgaas
AppliedQuoted 15 lines · Stephen Hemminger
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: [<ffffffff976b10bb>] rtnetlink_rcv+0x1b/0x40 #1: (&desc->request_mutex){+.+...}, at: [<ffffffff970ddd33>] __setup_irq+0xb3/0x720 #2: (&irq_desc_lock_class){-.-...}, at: [<ffffffff970ddd65>] __setup_irq+0xe5/0x720 irq event stamp: 3476 hardirqs last enabled at (3475): [<ffffffff971b3005>] get_page_from_freelist+0x225/0xc90 hardirqs last disabled at (3476): [<ffffffff978024e7>] _raw_spin_lock_irqsave+0x27/0x90 softirqs last enabled at (2446): [<ffffffffc05ef0b0>] ixgbevf_configure+0x380/0x7c0 [ixgbevf] softirqs last disabled at (2444): [<ffffffffc05ef08d>] ixgbevf_configure+0x35d/0x7c0 [ixgbevf]
Quoted 4 lines
The workaround is to poll for host response instead of blocking on completion.
Signed-off-by Stephen Hemminger <[email protected]>
Applied to pci/host-hv for v4.14, thanks!
Quoted 33 lines
--- drivers/pci/host/pci-hyperv.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)drivers/pci/host/pci-hyperv.c +7
-1@@ -50,6 +50,7 @@#include <linux/kernel.h> #include <linux/module.h> #include <linux/pci.h> +#include <linux/delay.h> #include <linux/semaphore.h> #include <linux/irqdomain.h> #include <asm/irqdomain.h> @@ -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,Signature · 1 line
2.11.0