From: Jia-Ju Bai Date: Wed, 18 Dec 2019 09:21:55 +0000 (+0800) Subject: net: nfc: nci: fix a possible sleep-in-atomic-context bug in nci_uart_tty_receive() X-Git-Tag: v4.19.92~212 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=5cc09cfdc35b2a092ac9402c6adf8e27d6c34daf;p=platform%2Fkernel%2Flinux-rpi.git net: nfc: nci: fix a possible sleep-in-atomic-context bug in nci_uart_tty_receive() [ 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/nfc/nci/uart.c b/net/nfc/nci/uart.c index a66f102..040576d 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; }