93ed54b15b
sysbot reported that we lack appropriate rcu_read_lock() protection in fib_dump_info_fnhe() net/ipv4/route.c:2875 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by syz-executor609/8966: #0: 00000000b7dbe288 (rtnl_mutex){+.+.}, at: netlink_dump+0xe7/0xfb0 net/netlink/af_netlink.c:2199 stack backtrace: CPU: 0 PID: 8966 Comm: syz-executor609 Not tainted 5.2.0-rc5+ #43 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5250 fib_dump_info_fnhe+0x9d9/0x1080 net/ipv4/route.c:2875 fn_trie_dump_leaf net/ipv4/fib_trie.c:2141 [inline] fib_table_dump+0x64a/0xd00 net/ipv4/fib_trie.c:2175 inet_dump_fib+0x83c/0xa90 net/ipv4/fib_frontend.c:1004 rtnl_dump_all+0x295/0x490 net/core/rtnetlink.c:3445 netlink_dump+0x558/0xfb0 net/netlink/af_netlink.c:2244 __netlink_dump_start+0x5b1/0x7d0 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:226 [inline] rtnetlink_rcv_msg+0x73d/0xb00 net/core/rtnetlink.c:5182 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5237 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:665 sock_write_iter+0x27c/0x3e0 net/socket.c:994 call_write_iter include/linux/fs.h:1872 [inline] new_sync_write+0x4d3/0x770 fs/read_write.c:483 __vfs_write+0xe1/0x110 fs/read_write.c:496 vfs_write+0x20c/0x580 fs/read_write.c:558 ksys_write+0x14f/0x290 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:620 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4401b9 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffc8e134978 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401b9 RDX: 000000000000001c RSI: 0000000020000000 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 R10: 0000000000000010 R11: 0000000000000246 R12: 0000000000401a40 R13: 0000000000401ad0 R14: 0000000000000000 R15: 0000000000000000 Fixes: ee28906fd7a1 ("ipv4: Dump route exceptions if requested") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Stefano Brivio <sbrivio@redhat.com> Cc: David Ahern <dsahern@gmail.com> Reported-by: syzbot <syzkaller@googlegroups.com> Reviewed-by: Stefano Brivio <sbrivio@redhat.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.