Commits
Ying Xue committed 66d95b6705a
tipc: fix suspicious RCU usage
When run tipcTS&tipcTC test suite, the following complaint appears:
[ 56.926168] ===============================
[ 56.926169] [ INFO: suspicious RCU usage. ]
[ 56.926171] 4.7.0-rc1+ #160 Not tainted
[ 56.926173] -------------------------------
[ 56.926174] net/tipc/bearer.c:408 suspicious rcu_dereference_protected() usage!
[ 56.926175]
[ 56.926175] other info that might help us debug this:
[ 56.926175]
[ 56.926177]
[ 56.926177] rcu_scheduler_active = 1, debug_locks = 1
[ 56.926179] 3 locks held by swapper/4/0:
[ 56.926180] #0: (((&req->timer))){+.-...}, at: [<ffffffff810e79b5>] call_timer_fn+0x5/0x340
[ 56.926203] #1: (&(&req->lock)->rlock){+.-...}, at: [<ffffffffa000c29b>] disc_timeout+0x1b/0xd0 [tipc]
[ 56.926212] #2: (rcu_read_lock){......}, at: [<ffffffffa00055e0>] tipc_bearer_xmit_skb+0xb0/0x2e0 [tipc]
[ 56.926218]
[ 56.926218] stack backtrace:
[ 56.926221] CPU: 4 PID: 0 Comm: swapper/4 Not tainted 4.7.0-rc1+ #160
[ 56.926222] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[ 56.926224] 0000000000000000 ffff880016803d28 ffffffff813c4423 ffff8800154252c0
[ 56.926227] 0000000000000001 ffff880016803d58 ffffffff810b7512 ffff8800124d8120
[ 56.926230] ffff880013f8a160 ffff8800132b5ccc ffff8800124d8120 ffff880016803d88
[ 56.926234] Call Trace:
[ 56.926235] <IRQ> [<ffffffff813c4423>] dump_stack+0x67/0x94
[ 56.926250] [<ffffffff810b7512>] lockdep_rcu_suspicious+0xe2/0x120
[ 56.926256] [<ffffffffa00051f1>] tipc_l2_send_msg+0x131/0x1c0 [tipc]
[ 56.926261] [<ffffffffa000567c>] tipc_bearer_xmit_skb+0x14c/0x2e0 [tipc]
[ 56.926266] [<ffffffffa00055e0>] ? tipc_bearer_xmit_skb+0xb0/0x2e0 [tipc]
[ 56.926273] [<ffffffffa000c280>] ? tipc_disc_init_msg+0x1f0/0x1f0 [tipc]
[ 56.926278] [<ffffffffa000c280>] ? tipc_disc_init_msg+0x1f0/0x1f0 [tipc]
[ 56.926283] [<ffffffffa000c2d6>] disc_timeout+0x56/0xd0 [tipc]
[ 56.926288] [<ffffffff810e7a68>] call_timer_fn+0xb8/0x340
[ 56.926291] [<ffffffff810e79b5>] ? call_timer_fn+0x5/0x340
[ 56.926296] [<ffffffffa000c280>] ? tipc_disc_init_msg+0x1f0/0x1f0 [tipc]
[ 56.926300] [<ffffffff810e8f4a>] run_timer_softirq+0x23a/0x390
[ 56.926306] [<ffffffff810f89ff>] ? clockevents_program_event+0x7f/0x130
[ 56.926316] [<ffffffff819727c3>] __do_softirq+0xc3/0x4a2
[ 56.926323] [<ffffffff8106ba5a>] irq_exit+0x8a/0xb0
[ 56.926327] [<ffffffff81972456>] smp_apic_timer_interrupt+0x46/0x60
[ 56.926331] [<ffffffff81970a49>] apic_timer_interrupt+0x89/0x90
[ 56.926333] <EOI> [<ffffffff81027fda>] ? default_idle+0x2a/0x1a0
[ 56.926340] [<ffffffff81027fd8>] ? default_idle+0x28/0x1a0
[ 56.926342] [<ffffffff810289cf>] arch_cpu_idle+0xf/0x20
[ 56.926345] [<ffffffff810adf0f>] default_idle_call+0x2f/0x50
[ 56.926347] [<ffffffff810ae145>] cpu_startup_entry+0x215/0x3e0
[ 56.926353] [<ffffffff81040ad9>] start_secondary+0xf9/0x100
The warning appears as rtnl_dereference() is wrongly used in
tipc_l2_send_msg() under RCU read lock protection. Instead the proper
usage should be that rcu_dereference_rtnl() is called here.
Fixes: 5b7066c3dd24 ("tipc: stricter filtering of packets in bearer layer")
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>