From 793c3b4000a1ef611ae7e5c89bd2a9c6b776cb5e Mon Sep 17 00:00:00 2001 From: Benjamin Block Date: Thu, 21 Aug 2014 19:37:48 +0200 Subject: [PATCH] net: ipv6: fib: don't sleep inside atomic lock 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: [] rtnl_lock+0x17/0x20 > #1: (&tb->tb6_lock){++--+.}, at: [] 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: > [] dump_stack+0x4e/0x68 > [] __might_sleep+0x10a/0x120 > [] kmem_cache_alloc_trace+0x4e/0x190 > [] ? fib6_commit_metrics+0x66/0x110 > [] fib6_commit_metrics+0x66/0x110 > [] fib6_add+0x883/0xa80 > [] ? ip6_route_add+0x65a/0x800 > [] ip6_route_add+0x675/0x800 > [] ? ip6_route_add+0x6a/0x800 > [] inet6_rtm_newroute+0x5c/0x80 > [] rtnetlink_rcv_msg+0x211/0x260 > [] ? rtnl_lock+0x17/0x20 > [] ? lock_release_holdtime+0x28/0x180 > [] ? rtnl_lock+0x17/0x20 > [] ? __rtnl_unlock+0x20/0x20 > [] netlink_rcv_skb+0x6e/0xd0 > [] rtnetlink_rcv+0x25/0x40 > [] netlink_unicast+0xd9/0x180 > [] netlink_sendmsg+0x700/0x770 > [] ? local_clock+0x25/0x30 > [] sock_sendmsg+0x6c/0x90 > [] ? might_fault+0xa3/0xb0 > [] ? verify_iovec+0x7d/0xf0 > [] ___sys_sendmsg+0x37e/0x3b0 > [] ? trace_hardirqs_on_caller+0x185/0x220 > [] ? mutex_unlock+0xe/0x10 > [] ? netlink_insert+0xbc/0xe0 > [] ? netlink_autobind.isra.30+0x125/0x150 > [] ? netlink_autobind.isra.30+0x60/0x150 > [] ? netlink_bind+0x159/0x230 > [] ? might_fault+0x5a/0xb0 > [] ? SYSC_bind+0x7e/0xd0 > [] __sys_sendmsg+0x4d/0x80 > [] SyS_sendmsg+0x12/0x20 > [] system_call_fastpath+0x16/0x1b Fixing this by replacing the mode GFP_KERNEL with GFP_ATOMIC. Signed-off-by: Benjamin Block Acked-by: David Rientjes Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- 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 cb4459bd1d29..76b7f5ee8f4c 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); -- 2.20.1