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[v6,1/6] phy: core: Fix that API devm_phy_put() fails to release the phy

Message ID 20241213-phy_core_fix-v6-1-40ae28f5015a@quicinc.com
State New
Headers show
Series phy: core: Fix bugs for several APIs and simplify an API | expand

Commit Message

Zijun Hu Dec. 13, 2024, 12:36 p.m. UTC 
From: Zijun Hu <quic_zijuhu@quicinc.com>

For devm_phy_put(), its comment says it needs to invoke phy_put() to
release the phy, but it will not actually invoke the function since
devres_destroy() does not call devm_phy_release(), and the missing
phy_put() call will cause:

- The phy fails to be released.
- devm_phy_put() can not fully undo what API devm_phy_get() does.
- Leak refcount of both the module and device for below typical usage:

  devm_phy_get(); // or its variant
  ...
  err = do_something();
  if (err)
      goto err_out;
  ...
  err_out:
  devm_phy_put(); // leak refcount here

  The file(s) affected by this issue are shown below since they have such
  typical usage.
  drivers/pci/controller/cadence/pcie-cadence.c
  drivers/net/ethernet/ti/am65-cpsw-nuss.c

Fix by using devres_release() instead of devres_destroy() within the API.

Fixes: ff764963479a ("drivers: phy: add generic PHY framework")
Cc: stable@vger.kernel.org
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Krzysztof Wilczyński <kw@linux.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
---
 drivers/phy/phy-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index f053b525ccffab1629f5e09581a6ebcc35e47f79..f190d7126613ad253b4820b9e4167dda8623439d 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -737,7 +737,7 @@  void devm_phy_put(struct device *dev, struct phy *phy)
 	if (!phy)
 		return;
 
-	r = devres_destroy(dev, devm_phy_release, devm_phy_match, phy);
+	r = devres_release(dev, devm_phy_release, devm_phy_match, phy);
 	dev_WARN_ONCE(dev, r, "couldn't find PHY resource\n");
 }
 EXPORT_SYMBOL_GPL(devm_phy_put);