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From: Yi Sun <yi.sun@intel.com>
To: vinicius.gomes@intel.com, dmaengine@vger.kernel.org,
	linux-kernel@vger.kernel.org
Cc: yi.sun@intel.com, gordon.jin@intel.com
Subject: [PATCH v2 2/2] dmaengine: idxd: Fix refcount underflow on module unload
Date: Sat,  7 Jun 2025 21:06:16 +0800	[thread overview]
Message-ID: <20250607130616.514984-3-yi.sun@intel.com> (raw)
In-Reply-To: <20250607130616.514984-1-yi.sun@intel.com>

A recent refactor introduced a misplaced put_device() call, leading to a
reference count underflow during module unload.

There is no need to add additional put_device() calls for idxd groups,
engines, or workqueues. Although commit a409e919ca3 claims:"Note, this
also fixes the missing put_device() for idxd groups, engines, and wqs."
It appears no such omission existed. The required cleanup is already
handled by the call chain:
idxd_unregister_devices() -> device_unregister() -> put_device()

Extend idxd_cleanup() to perform the necessary cleanup, and remove
idxd_cleanup_internals() which was not originally part of the driver
unload path and introduced unintended reference count underflow.

Fixes: a409e919ca32 ("dmaengine: idxd: Refactor remove call with idxd_cleanup() helper")
Signed-off-by: Yi Sun <yi.sun@intel.com>

diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 504aca0fd597..a5eabeb6a8bd 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -1321,7 +1321,12 @@ static void idxd_remove(struct pci_dev *pdev)
 	device_unregister(idxd_confdev(idxd));
 	idxd_shutdown(pdev);
 	idxd_device_remove_debugfs(idxd);
-	idxd_cleanup(idxd);
+	perfmon_pmu_remove(idxd);
+	idxd_cleanup_interrupts(idxd);
+	if (device_pasid_enabled(idxd))
+		idxd_disable_system_pasid(idxd);
+	if (device_user_pasid_enabled(idxd))
+		idxd_disable_sva(idxd->pdev);
 	pci_iounmap(pdev, idxd->reg_base);
 	put_device(idxd_confdev(idxd));
 	pci_disable_device(pdev);
-- 
2.43.0


  parent reply	other threads:[~2025-06-07 13:06 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-07 13:06 [PATCH v2 0/2] dmaengine: idxd: Fix refcount and cleanup issues on module unload Yi Sun
2025-06-07 13:06 ` [PATCH v2 1/2] dmaengine: idxd: Remove improper idxd_free Yi Sun
2025-06-07 13:06 ` Yi Sun [this message]
2025-06-13 23:20   ` [PATCH v2 2/2] dmaengine: idxd: Fix refcount underflow on module unload Vinicius Costa Gomes
2025-06-14  7:13     ` Yi Sun

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