| Message ID | 1408551366-24237-1-git-send-email-bebl@mageta.org |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On Mi, 2014-08-20 at 18:16 +0200, Benjamin Block wrote: > 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_NOWAIT. > > Signed-off-by: Benjamin Block <bebl@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..7eef9fc 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_NOWAIT); > if (!mp) > return -ENOMEM; > dst_init_metrics(dst, mp, 0); I actually think we should go with GFP_ATOMIC like the rest of the stack. The code path we are talking about here mostly uses GFP_ATOMIC, so in case this one GFP_NOWAITit bails out via error path, all those GFP_ATOMIC allocations before were useless. Bye, Hannes -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 14:54 Thu 21 Aug , Hannes Frederic Sowa wrote: > On Mi, 2014-08-20 at 18:16 +0200, Benjamin Block wrote: > > 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_NOWAIT. > > > > Signed-off-by: Benjamin Block <bebl@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..7eef9fc 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_NOWAIT); > > if (!mp) > > return -ENOMEM; > > dst_init_metrics(dst, mp, 0); > > I actually think we should go with GFP_ATOMIC like the rest of the > stack. The code path we are talking about here mostly uses GFP_ATOMIC, > so in case this one GFP_NOWAITit bails out via error path, all those > GFP_ATOMIC allocations before were useless. > Fair enough, I was thinking about it and was more along the line, the original author obviously wasn't concerned with any delay, and thus GFP_NOWAIT would suffice as well.
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index cb4459b..7eef9fc 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_NOWAIT); if (!mp) return -ENOMEM; dst_init_metrics(dst, mp, 0);