[ Upstream commit 690cc86321eb9bcee371710252742fb16fe96824 ] When CONFIG_IP_MULTICAST is not set and multicast ip is added to the device with autojoin flag or when multicast ip is deleted kernel will crash. steps to reproduce: ip addr add 224.0.0.0/32 dev eth0 ip addr del 224.0.0.0/32 dev eth0 or ip addr add 224.0.0.0/32 dev eth0 autojoin Unable to handle kernel NULL pointer dereference at virtual address 0000000000000088 pc : _raw_write_lock_irqsave+0x1e0/0x2ac lr : lock_sock_nested+0x1c/0x60 Call trace: _raw_write_lock_irqsave+0x1e0/0x2ac lock_sock_nested+0x1c/0x60 ip_mc_config.isra.28+0x50/0xe0 inet_rtm_deladdr+0x1a8/0x1f0 rtnetlink_rcv_msg+0x120/0x350 netlink_rcv_skb+0x58/0x120 rtnetlink_rcv+0x14/0x20 netlink_unicast+0x1b8/0x270 netlink_sendmsg+0x1a0/0x3b0 ____sys_sendmsg+0x248/0x290 ___sys_sendmsg+0x80/0xc0 __sys_sendmsg+0x68/0xc0 __arm64_sys_sendmsg+0x20/0x30 el0_svc_common.constprop.2+0x88/0x150 do_el0_svc+0x20/0x80 el0_sync_handler+0x118/0x190 el0_sync+0x140/0x180 Fixes: 93a714d6b53d ("multicast: Extend ip address command to enable multicast group join/leave on") Signed-off-by: Taras Chornyi <taras.chornyi@plvision.eu> Signed-off-by: Vadym Kochan <vadym.kochan@plvision.eu> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.
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