From: Jia-Ju Bai <baijiaju1990@xxxxxxxxx> [ Upstream commit b7ac893652cafadcf669f78452329727e4e255cc ] 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@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/nfc/nci/uart.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/nfc/nci/uart.c b/net/nfc/nci/uart.c index a66f102c6c01..040576dd73bb 100644 --- a/net/nfc/nci/uart.c +++ b/net/nfc/nci/uart.c @@ -348,7 +348,7 @@ 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; } -- 2.20.1
