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e198987e7d
gtp_encap_enable_socket() and gtp_encap_destroy() are not protected
by rcu_read_lock(). and it's not safe to write sk->sk_user_data.
This patch make these functions to use lock_sock() instead of
rcu_dereference_sk_user_data().
Test commands:
gtp-link add gtp1
Splat looks like:
[ 83.238315] =============================
[ 83.239127] WARNING: suspicious RCU usage
[ 83.239702] 5.2.0-rc6+ #49 Not tainted
[ 83.240268] -----------------------------
[ 83.241205] drivers/net/gtp.c:799 suspicious rcu_dereference_check() usage!
[ 83.243828]
[ 83.243828] other info that might help us debug this:
[ 83.243828]
[ 83.246325]
[ 83.246325] rcu_scheduler_active = 2, debug_locks = 1
[ 83.247314] 1 lock held by gtp-link/1008:
[ 83.248523] #0: 0000000017772c7f (rtnl_mutex){+.+.}, at: __rtnl_newlink+0x5f5/0x11b0
[ 83.251503]
[ 83.251503] stack backtrace:
[ 83.252173] CPU: 0 PID: 1008 Comm: gtp-link Not tainted 5.2.0-rc6+ #49
[ 83.253271] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 83.254562] Call Trace:
[ 83.254995] dump_stack+0x7c/0xbb
[ 83.255567] gtp_encap_enable_socket+0x2df/0x360 [gtp]
[ 83.256415] ? gtp_find_dev+0x1a0/0x1a0 [gtp]
[ 83.257161] ? memset+0x1f/0x40
[ 83.257843] gtp_newlink+0x90/0xa21 [gtp]
[ 83.258497] ? __netlink_ns_capable+0xc3/0xf0
[ 83.259260] __rtnl_newlink+0xb9f/0x11b0
[ 83.260022] ? rtnl_link_unregister+0x230/0x230
[ ... ]
Fixes: 1e3a3abd8b ("gtp: make GTP sockets in gtp_newlink optional")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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.