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From: Tong Zhang <ztong0001@gmail.com>
To: Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tong Zhang <ztong0001@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2] misc: alcor_pci: fix null-ptr-deref when there is no PCI bridge
Date: Tue, 11 May 2021 17:29:38 -0400	[thread overview]
Message-ID: <20210511212937.1269191-1-ztong0001@gmail.com> (raw)
In-Reply-To: <YJrFib6BD8JcX3DM@kroah.com>

Device might be attached to root complex directly. In this case,
bus->self(bridge) will be NULL, so we'd better check before use it

[    1.246492] BUG: kernel NULL pointer dereference, address: 00000000000000c0
[    1.248731] RIP: 0010:pci_read_config_byte+0x5/0x40
[    1.253998] Call Trace:
[    1.254131]  ? alcor_pci_find_cap_offset.isra.0+0x3a/0x100 [alcor_pci]
[    1.254476]  alcor_pci_probe+0x169/0x2d5 [alcor_pci]

Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Co-Developed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
v2: check before calling alcor_pci_find_cap_offset()

 drivers/misc/cardreader/alcor_pci.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/misc/cardreader/alcor_pci.c b/drivers/misc/cardreader/alcor_pci.c
index cd402c89189e..175c6b06f7aa 100644
--- a/drivers/misc/cardreader/alcor_pci.c
+++ b/drivers/misc/cardreader/alcor_pci.c
@@ -139,6 +139,9 @@ static void alcor_pci_init_check_aspm(struct alcor_pci_priv *priv)
 	u32 val32;
 
 	priv->pdev_cap_off    = alcor_pci_find_cap_offset(priv, priv->pdev);
+
+	if (!priv->parent_pdev)
+		return;
 	priv->parent_cap_off = alcor_pci_find_cap_offset(priv,
 							 priv->parent_pdev);
 
-- 
2.25.1


  reply	other threads:[~2021-05-11 21:32 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-26 22:07 [PATCH] misc: alcor_pci: fix null-ptr-deref when there is no PCI bridge Tong Zhang
2021-05-10 14:36 ` Greg Kroah-Hartman
2021-05-10 22:20   ` Tong Zhang
2021-05-11  7:03     ` Greg Kroah-Hartman
2021-05-11 17:17       ` Tong Zhang
2021-05-11 17:57         ` Greg Kroah-Hartman
2021-05-11 21:29           ` Tong Zhang [this message]
2021-05-12  6:24             ` [PATCH v2] " Greg Kroah-Hartman
2021-05-12 16:24               ` Tong Zhang
2021-05-12 16:41                 ` Greg Kroah-Hartman
2021-05-13  4:07                   ` [PATCH v3] " Tong Zhang
2021-05-19  8:40                     ` Dan Carpenter
2021-05-19 20:20                       ` Tong Zhang
2021-05-13  4:09                   ` [PATCH v2] " Tong Zhang
2021-05-11 21:32           ` [PATCH] " Tong Zhang

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