2019-08-07 02:47:06

by Fuqian Huang

[permalink] [raw]
Subject: [PATCH] libata-sff: use spin_lock_irqsave instead of spin_lock_irq in IRQ context.

Function ata_sff_flush_pio_task use spin_lock_irq/spin_unlock_irq
to protect shared data.
spin_unlock_irq will enable interrupts.

In the interrupt handler nv_swncq_interrupt (./drivers/ata/sata_nv.c),
when ap->link.sactive is true, nv_swncq_host_interrupt was called.
nv_swncq_hotplug is called when NV_SWNCQ_IRQ_HOTPLUG is set.
Then it will follow this chain:
nv_swncq_hotplug -> sata_scr_read (./dirvers/ata/libata-core.c)
-> sata_pmp_scr_read (./drivers/ata/libata-pmp.c)
-> sata_pmp_read -> ata_exec_internal
-> ata_exec_internal_sg -> ata_sff_flush_pio_task

Interrupts are enabled in interrupt handler.
Use spin_lock_irqsave instead of spin_lock_irq to avoid this.

Signed-off-by: Fuqian Huang <[email protected]>
---
drivers/ata/libata-sff.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 10aa27882142..d3143e7e6ec0 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -1241,6 +1241,7 @@ EXPORT_SYMBOL_GPL(ata_sff_queue_pio_task);

void ata_sff_flush_pio_task(struct ata_port *ap)
{
+ unsigned long flags;
DPRINTK("ENTER\n");

cancel_delayed_work_sync(&ap->sff_pio_task);
@@ -1253,9 +1254,9 @@ void ata_sff_flush_pio_task(struct ata_port *ap)
* __ata_sff_port_intr() checks for HSM_ST_IDLE and before it calls
* ata_sff_hsm_move() causing ata_sff_hsm_move() to BUG().
*/
- spin_lock_irq(ap->lock);
+ spin_lock_irqsave(ap->lock, flags);
ap->hsm_task_state = HSM_ST_IDLE;
- spin_unlock_irq(ap->lock);
+ spin_unlock_irqrestore(ap->lock, flags);

ap->sff_pio_task_link = NULL;

--
2.11.0