| Message ID | 20191218092155.5030-1-baijiaju1990@gmail.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | net: nfc: nci: fix a possible sleep-in-atomic-context bug in nci_uart_tty_receive() | expand |
From: Jia-Ju Bai <baijiaju1990@gmail.com> Date: Wed, 18 Dec 2019 17:21:55 +0800 > The kernel may sleep while holding a spinlock. > The function call path (from bottom to top) in Linux 4.19 is: > > net/nfc/nci/uart.c, 349: > nci_skb_alloc in nci_uart_default_recv_buf > net/nfc/nci/uart.c, 255: > (FUNC_PTR)nci_uart_default_recv_buf in nci_uart_tty_receive > net/nfc/nci/uart.c, 254: > spin_lock in nci_uart_tty_receive > > nci_skb_alloc(GFP_KERNEL) can sleep at runtime. > (FUNC_PTR) means a function pointer is called. > > To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC for > nci_skb_alloc(). > > This bug is found by a static analysis tool STCheck written by myself. > > Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Applied and queued up for -stable, thanks.
diff --git a/net/nfc/nci/uart.c b/net/nfc/nci/uart.c index 78fe622eba65..11b554ce07ff 100644 --- a/net/nfc/nci/uart.c +++ b/net/nfc/nci/uart.c @@ -346,7 +346,7 @@ static int nci_uart_default_recv_buf(struct nci_uart *nu, const u8 *data, nu->rx_packet_len = -1; nu->rx_skb = nci_skb_alloc(nu->ndev, NCI_MAX_PACKET_SIZE, - GFP_KERNEL); + GFP_ATOMIC); if (!nu->rx_skb) return -ENOMEM; }
The kernel may sleep while holding a spinlock. The function call path (from bottom to top) in Linux 4.19 is: net/nfc/nci/uart.c, 349: nci_skb_alloc in nci_uart_default_recv_buf net/nfc/nci/uart.c, 255: (FUNC_PTR)nci_uart_default_recv_buf in nci_uart_tty_receive net/nfc/nci/uart.c, 254: spin_lock in nci_uart_tty_receive nci_skb_alloc(GFP_KERNEL) can sleep at runtime. (FUNC_PTR) means a function pointer is called. To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC for nci_skb_alloc(). This bug is found by a static analysis tool STCheck written by myself. Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> --- net/nfc/nci/uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)