The function fib6_commit_metrics() allocates a piece of memory in mode GFP_KERNEL while holding an atomic lock from higher up in the stack, in the function __ip6_ins_rt(). This produces the following BUG:
> BUG: sleeping function called from invalid context at mm/slub.c:1250 > in_atomic(): 1, irqs_disabled(): 0, pid: 2909, name: dhcpcd > 2 locks held by dhcpcd/2909: > #0: (rtnl_mutex){+.+.+.}, at: [<ffffffff81978e67>] rtnl_lock+0x17/0x20 > #1: (&tb->tb6_lock){++--+.}, at: [<ffffffff81a6951a>] > ip6_route_add+0x65a/0x800 > CPU: 1 PID: 2909 Comm: dhcpcd Not tainted 3.17.0-rc1 #1 > Hardware name: ASUS All Series/Q87T, BIOS 0216 10/16/2013 > 0000000000000008 ffff8800c8f13858 ffffffff81af135a 0000000000000000 > ffff880212202430 ffff8800c8f13878 ffffffff810f8d3a ffff880212202c98 > 0000000000000010 ffff8800c8f138c8 ffffffff8121ad0e 0000000000000001 > Call Trace: > [<ffffffff81af135a>] dump_stack+0x4e/0x68 > [<ffffffff810f8d3a>] __might_sleep+0x10a/0x120 > [<ffffffff8121ad0e>] kmem_cache_alloc_trace+0x4e/0x190 > [<ffffffff81a6bcd6>] ? fib6_commit_metrics+0x66/0x110 > [<ffffffff81a6bcd6>] fib6_commit_metrics+0x66/0x110 > [<ffffffff81a6cbf3>] fib6_add+0x883/0xa80 > [<ffffffff81a6951a>] ? ip6_route_add+0x65a/0x800 > [<ffffffff81a69535>] ip6_route_add+0x675/0x800 > [<ffffffff81a68f2a>] ? ip6_route_add+0x6a/0x800 > [<ffffffff81a6990c>] inet6_rtm_newroute+0x5c/0x80 > [<ffffffff8197cf01>] rtnetlink_rcv_msg+0x211/0x260 > [<ffffffff81978e67>] ? rtnl_lock+0x17/0x20 > [<ffffffff81119708>] ? lock_release_holdtime+0x28/0x180 > [<ffffffff81978e67>] ? rtnl_lock+0x17/0x20 > [<ffffffff8197ccf0>] ? __rtnl_unlock+0x20/0x20 > [<ffffffff819a989e>] netlink_rcv_skb+0x6e/0xd0 > [<ffffffff81978ee5>] rtnetlink_rcv+0x25/0x40 > [<ffffffff819a8e59>] netlink_unicast+0xd9/0x180 > [<ffffffff819a9600>] netlink_sendmsg+0x700/0x770 > [<ffffffff81103735>] ? local_clock+0x25/0x30 > [<ffffffff8194e83c>] sock_sendmsg+0x6c/0x90 > [<ffffffff811f98e3>] ? might_fault+0xa3/0xb0 > [<ffffffff8195ca6d>] ? verify_iovec+0x7d/0xf0 > [<ffffffff8194ec3e>] ___sys_sendmsg+0x37e/0x3b0 > [<ffffffff8111ef15>] ? trace_hardirqs_on_caller+0x185/0x220 > [<ffffffff81af979e>] ? mutex_unlock+0xe/0x10 > [<ffffffff819a55ec>] ? netlink_insert+0xbc/0xe0 > [<ffffffff819a65e5>] ? netlink_autobind.isra.30+0x125/0x150 > [<ffffffff819a6520>] ? netlink_autobind.isra.30+0x60/0x150 > [<ffffffff819a84f9>] ? netlink_bind+0x159/0x230 > [<ffffffff811f989a>] ? might_fault+0x5a/0xb0 > [<ffffffff8194f25e>] ? SYSC_bind+0x7e/0xd0 > [<ffffffff8194f8cd>] __sys_sendmsg+0x4d/0x80 > [<ffffffff8194f912>] SyS_sendmsg+0x12/0x20 > [<ffffffff81afc692>] system_call_fastpath+0x16/0x1b Fixing this by replacing the mode GFP_KERNEL with GFP_ATOMIC. Signed-off-by: Benjamin Block <b...@mageta.org> --- net/ipv6/ip6_fib.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index cb4459b..76b7f5e 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -643,7 +643,7 @@ static int fib6_commit_metrics(struct dst_entry *dst, if (dst->flags & DST_HOST) { mp = dst_metrics_write_ptr(dst); } else { - mp = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL); + mp = kzalloc(sizeof(u32) * RTAX_MAX, GFP_ATOMIC); if (!mp) return -ENOMEM; dst_init_metrics(dst, mp, 0); -- 1.8.5.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/