[PATCH net 1/2] net: macb: Move devm_{free,request}_irq() out of spin lock area

[Kevin Hao <haokexin@gmail.com>]

The devm_free_irq() and devm_request_irq() functions should not be
executed in an atomic context.

During device suspend, all userspace processes and most kernel threads
are frozen. Additionally, we flush all tx/rx status, disable all macb
interrupts, and halt rx operations. Therefore, it is safe to split the
region protected by bp->lock into two independent sections, allowing
devm_free_irq() and devm_request_irq() to run in a non-atomic context.
This modification resolves the following lockdep warning:
  BUG: sleeping function called from invalid context at kernel/locking/mutex.c:591
  in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 501, name: rtcwake
  preempt_count: 1, expected: 0
  RCU nest depth: 1, expected: 0
  7 locks held by rtcwake/501:
   #0: ffff0008038c3408 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0xf8/0x368
   #1: ffff0008049a5e88 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0xbc/0x1c8
   #2: ffff00080098d588 (kn->active#70){.+.+}-{0:0}, at: kernfs_fop_write_iter+0xcc/0x1c8
   #3: ffff800081c84888 (system_transition_mutex){+.+.}-{4:4}, at: pm_suspend+0x1ec/0x290
   #4: ffff0008009ba0f8 (&dev->mutex){....}-{4:4}, at: device_suspend+0x118/0x4f0
   #5: ffff800081d00458 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire+0x4/0x48
   #6: ffff0008031fb9e0 (&bp->lock){-.-.}-{3:3}, at: macb_suspend+0x144/0x558
  irq event stamp: 8682
  hardirqs last  enabled at (8681): [<ffff8000813c7d7c>] _raw_spin_unlock_irqrestore+0x44/0x88
  hardirqs last disabled at (8682): [<ffff8000813c7b58>] _raw_spin_lock_irqsave+0x38/0x98
  softirqs last  enabled at (7322): [<ffff8000800f1b4c>] handle_softirqs+0x52c/0x588
  softirqs last disabled at (7317): [<ffff800080010310>] __do_softirq+0x20/0x2c
  CPU: 1 UID: 0 PID: 501 Comm: rtcwake Not tainted 7.0.0-rc3-next-20260310-yocto-standard+ #125 PREEMPT
  Hardware name: ZynqMP ZCU102 Rev1.1 (DT)
  Call trace:
   show_stack+0x24/0x38 (C)
   __dump_stack+0x28/0x38
   dump_stack_lvl+0x64/0x88
   dump_stack+0x18/0x24
   __might_resched+0x200/0x218
   __might_sleep+0x38/0x98
   __mutex_lock_common+0x7c/0x1378
   mutex_lock_nested+0x38/0x50
   free_irq+0x68/0x2b0
   devm_irq_release+0x24/0x38
   devres_release+0x40/0x80
   devm_free_irq+0x48/0x88
   macb_suspend+0x298/0x558
   device_suspend+0x218/0x4f0
   dpm_suspend+0x244/0x3a0
   dpm_suspend_start+0x50/0x78
   suspend_devices_and_enter+0xec/0x560
   pm_suspend+0x194/0x290
   state_store+0x110/0x158
   kobj_attr_store+0x1c/0x30
   sysfs_kf_write+0xa8/0xd0
   kernfs_fop_write_iter+0x11c/0x1c8
   vfs_write+0x248/0x368
   ksys_write+0x7c/0xf8
   __arm64_sys_write+0x28/0x40
   invoke_syscall+0x4c/0xe8
   el0_svc_common+0x98/0xf0
   do_el0_svc+0x28/0x40
   el0_svc+0x54/0x1e0
   el0t_64_sync_handler+0x84/0x130
   el0t_64_sync+0x198/0x1a0

Fixes: 558e35ccfe95 ("net: macb: WoL support for GEM type of Ethernet controller")
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Cc: stable@vger.kernel.org
---
 drivers/net/ethernet/cadence/macb_main.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index ae5f0c95cf9b5df17aa34333175400f1bf1e2621..f290bc44020e76e681f403306cba998e540a4991 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -5962,6 +5962,7 @@ static int __maybe_unused macb_suspend(struct device *dev)
 			/* write IP address into register */
 			tmp |= MACB_BFEXT(IP, be32_to_cpu(ifa->ifa_local));
 		}
+		spin_unlock_irqrestore(&bp->lock, flags);
 
 		/* Change interrupt handler and
 		 * Enable WoL IRQ on queue 0
@@ -5974,11 +5975,12 @@ static int __maybe_unused macb_suspend(struct device *dev)
 				dev_err(dev,
 					"Unable to request IRQ %d (error %d)\n",
 					bp->queues[0].irq, err);
-				spin_unlock_irqrestore(&bp->lock, flags);
 				return err;
 			}
+			spin_lock_irqsave(&bp->lock, flags);
 			queue_writel(bp->queues, IER, GEM_BIT(WOL));
 			gem_writel(bp, WOL, tmp);
+			spin_unlock_irqrestore(&bp->lock, flags);
 		} else {
 			err = devm_request_irq(dev, bp->queues[0].irq, macb_wol_interrupt,
 					       IRQF_SHARED, netdev->name, bp->queues);
@@ -5986,13 +5988,13 @@ static int __maybe_unused macb_suspend(struct device *dev)
 				dev_err(dev,
 					"Unable to request IRQ %d (error %d)\n",
 					bp->queues[0].irq, err);
-				spin_unlock_irqrestore(&bp->lock, flags);
 				return err;
 			}
+			spin_lock_irqsave(&bp->lock, flags);
 			queue_writel(bp->queues, IER, MACB_BIT(WOL));
 			macb_writel(bp, WOL, tmp);
+			spin_unlock_irqrestore(&bp->lock, flags);
 		}
-		spin_unlock_irqrestore(&bp->lock, flags);
 
 		enable_irq_wake(bp->queues[0].irq);
 	}
@@ -6059,6 +6061,8 @@ static int __maybe_unused macb_resume(struct device *dev)
 		queue_readl(bp->queues, ISR);
 		if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE)
 			queue_writel(bp->queues, ISR, -1);
+		spin_unlock_irqrestore(&bp->lock, flags);
+
 		/* Replace interrupt handler on queue 0 */
 		devm_free_irq(dev, bp->queues[0].irq, bp->queues);
 		err = devm_request_irq(dev, bp->queues[0].irq, macb_interrupt,
@@ -6067,10 +6071,8 @@ static int __maybe_unused macb_resume(struct device *dev)
 			dev_err(dev,
 				"Unable to request IRQ %d (error %d)\n",
 				bp->queues[0].irq, err);
-			spin_unlock_irqrestore(&bp->lock, flags);
 			return err;
 		}
-		spin_unlock_irqrestore(&bp->lock, flags);
 
 		disable_irq_wake(bp->queues[0].irq);
 

-- 
2.53.0