This is a note to let you know that I've just added the patch titled
IB/hfi1: Fix potential deadlock on &irq_src_lock and &dd->uctxt_lock
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ib-hfi1-fix-potential-deadlock-on-irq_src_lock-and-d.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8665f66a553821a2a9f3406c883b1263de90984c
Author: Chengfeng Ye <dg573847474@xxxxxxxxx>
Date: Tue Sep 26 10:11:16 2023 +0000
IB/hfi1: Fix potential deadlock on &irq_src_lock and &dd->uctxt_lock
[ Upstream commit 2f19c4b8395ccb6eb25ccafee883c8cfbe3fc193 ]
handle_receive_interrupt_napi_sp() running inside interrupt handler
could introduce inverse lock ordering between &dd->irq_src_lock
and &dd->uctxt_lock, if read_mod_write() is preempted by the isr.
[CPU0] | [CPU1]
hfi1_ipoib_dev_open() |
--> hfi1_netdev_enable_queues() |
--> enable_queues(rx) |
--> hfi1_rcvctrl() |
--> set_intr_bits() |
--> read_mod_write() |
--> spin_lock(&dd->irq_src_lock) |
| hfi1_poll()
| --> poll_next()
| --> spin_lock_irq(&dd->uctxt_lock)
|
| --> hfi1_rcvctrl()
| --> set_intr_bits()
| --> read_mod_write()
| --> spin_lock(&dd->irq_src_lock)
<interrupt> |
--> handle_receive_interrupt_napi_sp() |
--> set_all_fastpath() |
--> hfi1_rcd_get_by_index() |
--> spin_lock_irqsave(&dd->uctxt_lock) |
This flaw was found by an experimental static analysis tool I am
developing for irq-related deadlock.
To prevent the potential deadlock, the patch use spin_lock_irqsave()
on &dd->irq_src_lock inside read_mod_write() to prevent the possible
deadlock scenario.
Signed-off-by: Chengfeng Ye <dg573847474@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230926101116.2797-1-dg573847474@xxxxxxxxx
Acked-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/infiniband/hw/hfi1/chip.c b/drivers/infiniband/hw/hfi1/chip.c
index 65d6bf34614c8..6cf87fcfc4eb5 100644
--- a/drivers/infiniband/hw/hfi1/chip.c
+++ b/drivers/infiniband/hw/hfi1/chip.c
@@ -13067,15 +13067,16 @@ static void read_mod_write(struct hfi1_devdata *dd, u16 src, u64 bits,
{
u64 reg;
u16 idx = src / BITS_PER_REGISTER;
+ unsigned long flags;
- spin_lock(&dd->irq_src_lock);
+ spin_lock_irqsave(&dd->irq_src_lock, flags);
reg = read_csr(dd, CCE_INT_MASK + (8 * idx));
if (set)
reg |= bits;
else
reg &= ~bits;
write_csr(dd, CCE_INT_MASK + (8 * idx), reg);
- spin_unlock(&dd->irq_src_lock);
+ spin_unlock_irqrestore(&dd->irq_src_lock, flags);
}
/**
