0a6e6b3c7d
In the past, free_fib_info() was supposed to be called under RTNL protection. This eventually was no longer the case. Instead of enforcing RTNL it seems we simply can move fib_info_cnt changes to occur when fib_info_lock is held. v2: David Laight suggested to update fib_info_cnt only when an entry is added/deleted to/from the hash table, as fib_info_cnt is used to make sure hash table size is optimal. BUG: KCSAN: data-race in fib_create_info / free_fib_info write to 0xffffffff86e243a0 of 4 bytes by task 26429 on cpu 0: fib_create_info+0xe78/0x3440 net/ipv4/fib_semantics.c:1428 fib_table_insert+0x148/0x10c0 net/ipv4/fib_trie.c:1224 fib_magic+0x195/0x1e0 net/ipv4/fib_frontend.c:1087 fib_add_ifaddr+0xd0/0x2e0 net/ipv4/fib_frontend.c:1109 fib_netdev_event+0x178/0x510 net/ipv4/fib_frontend.c:1466 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0x53/0xb0 kernel/notifier.c:391 __dev_notify_flags+0x1d3/0x3b0 dev_change_flags+0xa2/0xc0 net/core/dev.c:8872 do_setlink+0x810/0x2410 net/core/rtnetlink.c:2719 rtnl_group_changelink net/core/rtnetlink.c:3242 [inline] __rtnl_newlink net/core/rtnetlink.c:3396 [inline] rtnl_newlink+0xb10/0x13b0 net/core/rtnetlink.c:3506 rtnetlink_rcv_msg+0x745/0x7e0 net/core/rtnetlink.c:5571 netlink_rcv_skb+0x14e/0x250 net/netlink/af_netlink.c:2496 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:5589 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x5fc/0x6c0 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x726/0x840 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] ____sys_sendmsg+0x39a/0x510 net/socket.c:2409 ___sys_sendmsg net/socket.c:2463 [inline] __sys_sendmsg+0x195/0x230 net/socket.c:2492 __do_sys_sendmsg net/socket.c:2501 [inline] __se_sys_sendmsg net/socket.c:2499 [inline] __x64_sys_sendmsg+0x42/0x50 net/socket.c:2499 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffffffff86e243a0 of 4 bytes by task 31505 on cpu 1: free_fib_info+0x35/0x80 net/ipv4/fib_semantics.c:252 fib_info_put include/net/ip_fib.h:575 [inline] nsim_fib4_rt_destroy drivers/net/netdevsim/fib.c:294 [inline] nsim_fib4_rt_replace drivers/net/netdevsim/fib.c:403 [inline] nsim_fib4_rt_insert drivers/net/netdevsim/fib.c:431 [inline] nsim_fib4_event drivers/net/netdevsim/fib.c:461 [inline] nsim_fib_event drivers/net/netdevsim/fib.c:881 [inline] nsim_fib_event_work+0x15ca/0x2cf0 drivers/net/netdevsim/fib.c:1477 process_one_work+0x3fc/0x980 kernel/workqueue.c:2298 process_scheduled_works kernel/workqueue.c:2361 [inline] worker_thread+0x7df/0xa70 kernel/workqueue.c:2447 kthread+0x2c7/0x2e0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 value changed: 0x00000d2d -> 0x00000d2e Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 31505 Comm: kworker/1:21 Not tainted 5.16.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events nsim_fib_event_work Fixes: 48bb9eb47b27 ("netdevsim: fib: Add dummy implementation for FIB offload") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Ido Schimmel <idosch@mellanox.com> Cc: Jiri Pirko <jiri@mellanox.com> Reviewed-by: Ido Schimmel <idosch@nvidia.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.