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| author | Yinhao Hu <dddddd@hust.edu.cn> | 2026-06-26 00:34:34 -0700 |
|---|---|---|
| committer | David Heidelberg <david@ixit.cz> | 2026-08-17 19:27:49 +0200 |
| commit | 4b992fb2ce3e7bb394b3d57e2bf22928e70cfb83 (patch) | |
| tree | 1e7be75a1de417d53717f3769dcc1887143c17ad | |
| parent | 04ab4a1f5c3c325fcbf5c90cb22c67e5ca107bb5 (diff) | |
| download | linux-next-4b992fb2ce3e7bb394b3d57e2bf22928e70cfb83.tar.gz linux-next-4b992fb2ce3e7bb394b3d57e2bf22928e70cfb83.zip | |
nfc: pn533: hold a reference to the request skb during send_frame
__pn533_send_async() publishes the command and then calls
dev->phy_ops->send_frame(). Once dev->cmd is set, an incoming frame
can be matched to this command: the I2C threaded IRQ runs
pn533_recv_frame(), which queues cmd_complete_work, and
pn533_send_async_complete() frees cmd->req with consume_skb().
On the I2C transport, pn533_i2c_send_frame() still dereferences the same
skb after i2c_master_send() returns, so a completion that races the
send can free the skb while the transport is still using it.
The request skb is owned by the command object and may be freed by
command completion at any time after dev->cmd is published, so the
transport send path must not assume it stays alive. Hold a temporary
reference to the request skb across the send_frame() call so the
transport always sees a live skb even if completion races the send.
Add a pn533_send_cmd_frame() helper and use it from all three send
paths.
Fixes: 9815c7cf22da ("NFC: pn533: Separate physical layer from the core implementation")
Signed-off-by: Yinhao Hu <dddddd@hust.edu.cn>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260626073434.3977525-1-dddddd@hust.edu.cn
Signed-off-by: David Heidelberg <david@ixit.cz>
| -rw-r--r-- | drivers/nfc/pn533/pn533.c | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/nfc/pn533/pn533.c b/drivers/nfc/pn533/pn533.c index d7bdbc82e2ba..55bbfa32d695 100644 --- a/drivers/nfc/pn533/pn533.c +++ b/drivers/nfc/pn533/pn533.c @@ -434,6 +434,18 @@ done: return rc; } +static int pn533_send_cmd_frame(struct pn533 *dev, struct pn533_cmd *cmd) +{ + struct sk_buff *req = cmd->req; + int rc; + + skb_get(req); + dev->cmd = cmd; + rc = dev->phy_ops->send_frame(dev, req); + dev_kfree_skb(req); + return rc; +} + static int __pn533_send_async(struct pn533 *dev, u8 cmd_code, struct sk_buff *req, pn533_send_async_complete_t complete_cb, @@ -458,8 +470,7 @@ static int __pn533_send_async(struct pn533 *dev, u8 cmd_code, mutex_lock(&dev->cmd_lock); if (!dev->cmd_pending) { - dev->cmd = cmd; - rc = dev->phy_ops->send_frame(dev, req); + rc = pn533_send_cmd_frame(dev, cmd); if (rc) { dev->cmd = NULL; goto error; @@ -529,8 +540,7 @@ static int pn533_send_cmd_direct_async(struct pn533 *dev, u8 cmd_code, pn533_build_cmd_frame(dev, cmd_code, req); - dev->cmd = cmd; - rc = dev->phy_ops->send_frame(dev, req); + rc = pn533_send_cmd_frame(dev, cmd); if (rc < 0) { dev->cmd = NULL; kfree(cmd); @@ -569,8 +579,7 @@ static void pn533_wq_cmd(struct work_struct *work) mutex_unlock(&dev->cmd_lock); - dev->cmd = cmd; - rc = dev->phy_ops->send_frame(dev, cmd->req); + rc = pn533_send_cmd_frame(dev, cmd); if (rc < 0) { dev->cmd = NULL; dev_kfree_skb(cmd->req); |