Jia-Ju Bai f46b81843d 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 <baijiaju1990@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-31 12:36:41 +01:00
2019-12-17 20:39:21 +01:00
2019-12-21 10:47:56 +01:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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