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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: dave.jiang@intel.com, yi.sun@intel.com, gordon.jin@intel.com,
	fenghuay@nvidia.com
Subject: [PATCH v3 2/2] dmaengine: idxd: Fix refcount underflow on module unload
Date: Tue, 17 Jun 2025 18:27:12 +0800	[thread overview]
Message-ID: <20250617102712.727333-3-yi.sun@intel.com> (raw)
In-Reply-To: <20250617102712.727333-1-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 40cc9c070081..40f4bf446763 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -1292,7 +1292,10 @@ 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);
 	pci_iounmap(pdev, idxd->reg_base);
 	put_device(idxd_confdev(idxd));
 	pci_disable_device(pdev);
-- 
2.43.0


  parent reply	other threads:[~2025-06-17 10:27 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-17 10:27 [PATCH v3 0/2] dmaengine: idxd: Fix refcount and cleanup issues on module unload Yi Sun
2025-06-17 10:27 ` [PATCH v3 1/2] dmaengine: idxd: Remove improper idxd_free Yi Sun
2025-06-17 22:13   ` Fenghua Yu
2025-07-27  9:02     ` Yi Sun
2025-07-28  8:21       ` Shuai Xue
2025-06-17 10:27 ` Yi Sun [this message]
2025-06-17 21:58   ` [PATCH v3 2/2] dmaengine: idxd: Fix refcount underflow on module unload Fenghua Yu
2025-06-18  0:38     ` Vinicius Costa Gomes
2025-07-27  9:16     ` Yi Sun
2025-07-28  8:40       ` Shuai Xue
2025-07-28 11:43         ` Yi Sun
2025-07-29  2:46           ` Shuai Xue
2025-07-29  3:15             ` Yi Sun
2025-07-29  6:00               ` Shuai Xue
2025-07-31  0:17             ` Vinicius Costa Gomes

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