5ce76fe1ee
Fix the following kernel warning in veth_set_xdp_features routine relying on rtnl_dereference() instead of on rcu_dereference(): ============================= WARNING: suspicious RCU usage 6.3.0-rc1-00144-g064d70527aaa #149 Not tainted ----------------------------- drivers/net/veth.c:1265 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by ip/135: (net/core/rtnetlink.c:6172) stack backtrace: CPU: 1 PID: 135 Comm: ip Not tainted 6.3.0-rc1-00144-g064d70527aaa #149 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:107) lockdep_rcu_suspicious (include/linux/context_tracking.h:152) veth_set_xdp_features (drivers/net/veth.c:1265 (discriminator 9)) veth_newlink (drivers/net/veth.c:1892) ? veth_set_features (drivers/net/veth.c:1774) ? kasan_save_stack (mm/kasan/common.c:47) ? kasan_save_stack (mm/kasan/common.c:46) ? kasan_set_track (mm/kasan/common.c:52) ? alloc_netdev_mqs (include/linux/slab.h:737) ? rcu_read_lock_sched_held (kernel/rcu/update.c:125) ? trace_kmalloc (include/trace/events/kmem.h:54) ? __xdp_rxq_info_reg (net/core/xdp.c:188) ? alloc_netdev_mqs (net/core/dev.c:10657) ? rtnl_create_link (net/core/rtnetlink.c:3312) rtnl_newlink_create (net/core/rtnetlink.c:3440) ? rtnl_link_get_net_capable.constprop.0 (net/core/rtnetlink.c:3391) __rtnl_newlink (net/core/rtnetlink.c:3657) ? lock_downgrade (kernel/locking/lockdep.c:5321) ? rtnl_link_unregister (net/core/rtnetlink.c:3487) rtnl_newlink (net/core/rtnetlink.c:3671) rtnetlink_rcv_msg (net/core/rtnetlink.c:6174) ? rtnl_link_fill (net/core/rtnetlink.c:6070) ? mark_usage (kernel/locking/lockdep.c:4914) ? mark_usage (kernel/locking/lockdep.c:4914) netlink_rcv_skb (net/netlink/af_netlink.c:2574) ? rtnl_link_fill (net/core/rtnetlink.c:6070) ? netlink_ack (net/netlink/af_netlink.c:2551) ? lock_acquire (kernel/locking/lockdep.c:467) ? net_generic (include/linux/rcupdate.h:805) ? netlink_deliver_tap (include/linux/rcupdate.h:805) netlink_unicast (net/netlink/af_netlink.c:1340) ? netlink_attachskb (net/netlink/af_netlink.c:1350) netlink_sendmsg (net/netlink/af_netlink.c:1942) ? netlink_unicast (net/netlink/af_netlink.c:1861) ? netlink_unicast (net/netlink/af_netlink.c:1861) sock_sendmsg (net/socket.c:727) ____sys_sendmsg (net/socket.c:2501) ? kernel_sendmsg (net/socket.c:2448) ? __copy_msghdr (net/socket.c:2428) ___sys_sendmsg (net/socket.c:2557) ? mark_usage (kernel/locking/lockdep.c:4914) ? do_recvmmsg (net/socket.c:2544) ? lock_acquire (kernel/locking/lockdep.c:467) ? find_held_lock (kernel/locking/lockdep.c:5159) ? __lock_release (kernel/locking/lockdep.c:5345) ? __might_fault (mm/memory.c:5625) ? lock_downgrade (kernel/locking/lockdep.c:5321) ? __fget_light (include/linux/atomic/atomic-arch-fallback.h:227) __sys_sendmsg (include/linux/file.h:31) ? __sys_sendmsg_sock (net/socket.c:2572) ? rseq_get_rseq_cs (kernel/rseq.c:275) ? lockdep_hardirqs_on_prepare.part.0 (kernel/locking/lockdep.c:4263) do_syscall_64 (arch/x86/entry/common.c:50) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) RIP: 0033:0x7f0d1aadeb17 Code: 0f 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10 Fixes: fccca038f300 ("veth: take into account device reconfiguration for xdp_features flag") Suggested-by: Eric Dumazet <edumazet@google.com> Reported-by: Matthieu Baerts <matthieu.baerts@tessares.net> Link: https://lore.kernel.org/netdev/cover.1678364612.git.lorenzo@kernel.org/T/#me4c9d8e985ec7ebee981cfdb5bc5ec651ef4035d Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> Reported-by: syzbot+c3d0d9c42d59ff644ea6@syzkaller.appspotmail.com Reviewed-by: Eric Dumazet <edumazet@google.com> Tested-by: Matthieu Baerts <matthieu.baerts@tessares.net> Link: https://lore.kernel.org/r/dfd6a9a7d85e9113063165e1f47b466b90ad7b8a.1678748579.git.lorenzo@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.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.