From: Ira Weiny <ira.weiny@intel.com>
To: Dan Williams <dan.j.williams@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Joao Martins <joao.m.martins@oracle.com>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Yongqiang Liu <liuyongqiang13@huawei.com>,
Paul Cassella <cassella@hpe.com>,
linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev,
linux-cxl@vger.kernel.org, Ira Weiny <ira.weiny@intel.com>
Subject: [PATCH RFC 1/4] dax/bus: Fix leaked reference in alloc_dax_region()
Date: Fri, 02 Jun 2023 19:09:21 -0700 [thread overview]
Message-ID: <20230602-dax-region-put-v1-1-d8668f335d45@intel.com> (raw)
In-Reply-To: <20230602-dax-region-put-v1-0-d8668f335d45@intel.com>
kref_init() initializes the ref count to 1. An extra kref is taken on
the dax_region to be used by the caller. If devm_add_action_or_reset()
fails this extra reference is leaked.
Drop the extra reference on error.
Fixes: d7fe1a67f658 ("dax: add region 'id', 'size', and 'align' attributes")
Cc: Dan Williams <dan.j.williams@intel.com
Suggested-by: Paul Cassella <cassella@hpe.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
drivers/dax/bus.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 227800053309..899e29d107b4 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -583,6 +583,7 @@ static void dax_region_unregister(void *region)
dax_region_put(dax_region);
}
+/* The dax_region reference returned should be dropped with dax_region_put() */
struct dax_region *alloc_dax_region(struct device *parent, int region_id,
struct range *range, int target_node, unsigned int align,
unsigned long flags)
@@ -625,9 +626,13 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id,
return NULL;
}
+ /* Hold a reference to return to the caller */
kref_get(&dax_region->kref);
- if (devm_add_action_or_reset(parent, dax_region_unregister, dax_region))
+ if (devm_add_action_or_reset(parent, dax_region_unregister,
+ dax_region)) {
+ kref_put(&dax_region->kref, dax_region_free);
return NULL;
+ }
return dax_region;
}
EXPORT_SYMBOL_GPL(alloc_dax_region);
--
2.40.0
next prev parent reply other threads:[~2023-06-03 2:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-03 2:09 [PATCH RFC 0/4] dax: Clean up dax_region references Ira Weiny
2023-06-03 2:09 ` Ira Weiny [this message]
2023-06-03 2:09 ` [PATCH RFC 2/4] dax/hmem: Fix refcount leak in dax_hmem_probe() ira.weiny
2023-06-03 2:09 ` [PATCH RFC 3/4] dax/cxl: Fix refcount leak in cxl_dax_region_probe() Ira Weiny
2023-06-03 2:09 ` [PATCH RFC 4/4] dax/bus: Remove unnecessary reference in alloc_dax_region() Ira Weiny
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