mirror of
https://github.com/torvalds/linux.git
synced 2024-09-21 07:23:06 +00:00
A mirror of the official Linux kernel repository just in case
59259ff7a8
There is a crash in the function br_get_link_af_size_filtered,
as the port_exists(dev) is true and the rx_handler_data of dev is NULL.
But the rx_handler_data of dev is correct saved in vmcore.
The oops looks something like:
...
pc : br_get_link_af_size_filtered+0x28/0x1c8 [bridge]
...
Call trace:
br_get_link_af_size_filtered+0x28/0x1c8 [bridge]
if_nlmsg_size+0x180/0x1b0
rtnl_calcit.isra.12+0xf8/0x148
rtnetlink_rcv_msg+0x334/0x370
netlink_rcv_skb+0x64/0x130
rtnetlink_rcv+0x28/0x38
netlink_unicast+0x1f0/0x250
netlink_sendmsg+0x310/0x378
sock_sendmsg+0x4c/0x70
__sys_sendto+0x120/0x150
__arm64_sys_sendto+0x30/0x40
el0_svc_common+0x78/0x130
el0_svc_handler+0x38/0x78
el0_svc+0x8/0xc
In br_add_if(), we found there is no guarantee that
assigning rx_handler_data to dev->rx_handler_data
will before setting the IFF_BRIDGE_PORT bit of priv_flags.
So there is a possible data competition:
CPU 0: CPU 1:
(RCU read lock) (RTNL lock)
rtnl_calcit() br_add_slave()
if_nlmsg_size() br_add_if()
br_get_link_af_size_filtered() -> netdev_rx_handler_register
...
// The order is not guaranteed
... -> dev->priv_flags |= IFF_BRIDGE_PORT;
// The IFF_BRIDGE_PORT bit of priv_flags has been set
-> if (br_port_exists(dev)) {
// The dev->rx_handler_data has NOT been assigned
-> p = br_port_get_rcu(dev);
....
-> rcu_assign_pointer(dev->rx_handler_data, rx_handler_data);
...
Fix it in br_get_link_af_size_filtered, using br_port_get_check_rcu() and checking the return value.
Signed-off-by: Zhang Zhengming <zhangzhengming@huawei.com>
Reviewed-by: Zhao Lei <zhaolei69@huawei.com>
Reviewed-by: Wang Xiaogang <wangxiaogang3@huawei.com>
Suggested-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.