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[net,2/2] net: ethernet: ftgmac100: fix NULL phy usage on device remove

Message ID 20241028-ftgmac-fixes-v1-2-b334a507be6c@codeconstruct.com.au (mailing list archive)
State New
Delegated to: Netdev Maintainers
Headers show
Series net: ethernet: ftgmac100: fixes for ncsi/phy handling on device remove | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 3 this patch: 3
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 3 this patch: 3
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 20 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest fail net-next-2024-10-28--06-00 (tests: 773)

Commit Message

Jeremy Kerr Oct. 28, 2024, 4:54 a.m. UTC
Commit e24a6c874601 ("net: ftgmac100: Get link speed and duplex for
NC-SI") introduced a fixed phydev attached to the ftgmac netdev for ncsi
configurations, cleaned up on remove as:

    phy_disconnect(netdev->phydev);

    /* ... */

    if (priv->use_ncsi)
        fixed_phy_unregister(netdev->phydev);

However, phy_disconnect() will clear the netdev's ->phydev pointer, so
the fixed_phy_unregister() will always be invoked with a null pointer.

Use a temporary for the phydev, rather than expecting the netdev->phydev
point to be valid over the phy_disconnect().

Fixes: e24a6c874601 ("net: ftgmac100: Get link speed and duplex for NC-SI")
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
---
 drivers/net/ethernet/faraday/ftgmac100.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Comments

Jacky Chou Oct. 28, 2024, 5:58 a.m. UTC | #1
Hi Jeremy,

I checked the phy_disconnect function again.
It will assign NULL pointer to netdev->phydev after calling itself.
In NC-SI mode, it does cause a crash when calling fixed_phy_unregister(netdev->phydev).
Thank you for your help in pointing out my mistack.

Thanks,
Jacky

Reviewed-by: Jacky Chou <jacky_chou@aspeedtech.com>
diff mbox series

Patch

diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 9caee68468ff5f71d7ea63a0c8c9ec2be4a718bc..c6ed7ed0e2389a45a671b85ae60936df99458cd1 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -1730,16 +1730,17 @@  static int ftgmac100_setup_mdio(struct net_device *netdev)
 static void ftgmac100_phy_disconnect(struct net_device *netdev)
 {
 	struct ftgmac100 *priv = netdev_priv(netdev);
+	struct phy_device *phydev = netdev->phydev;
 
-	if (!netdev->phydev)
+	if (!phydev)
 		return;
 
-	phy_disconnect(netdev->phydev);
+	phy_disconnect(phydev);
 	if (of_phy_is_fixed_link(priv->dev->of_node))
 		of_phy_deregister_fixed_link(priv->dev->of_node);
 
 	if (priv->use_ncsi)
-		fixed_phy_unregister(netdev->phydev);
+		fixed_phy_unregister(phydev);
 }
 
 static void ftgmac100_destroy_mdio(struct net_device *netdev)