pn532_receive_buf() appends every incoming byte to dev->recv_skb and
only resets the buffer after pn532_uart_rx_is_frame() recognizes a
complete frame. A continuous stream of bytes without a valid PN532 frame
header therefore keeps growing the skb until skb_put_u8() hits the tail
limit.
Drop the accumulated partial frame once the fixed receive buffer is full
so malformed UART traffic cannot grow the skb past
PN532_UART_SKB_BUFF_LEN.
Fixes: c656aa4c27 ("nfc: pn533: add UART phy driver")
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Link: https://patch.msgid.link/20260326142033.82297-1-pengpeng@iscas.ac.cn
Signed-off-by: Paolo Abeni <pabeni@redhat.com>