| From foo@baz Sun Nov 22 12:00:04 PM CET 2020 |
| From: Xin Long <lucien.xin@gmail.com> |
| Date: Sat, 14 Nov 2020 13:22:53 +0800 |
| Subject: sctp: change to hold/put transport for proto_unreach_timer |
| |
| From: Xin Long <lucien.xin@gmail.com> |
| |
| [ Upstream commit 057a10fa1f73d745c8e69aa54ab147715f5630ae ] |
| |
| A call trace was found in Hangbin's Codenomicon testing with debug kernel: |
| |
| [ 2615.981988] ODEBUG: free active (active state 0) object type: timer_list hint: sctp_generate_proto_unreach_event+0x0/0x3a0 [sctp] |
| [ 2615.995050] WARNING: CPU: 17 PID: 0 at lib/debugobjects.c:328 debug_print_object+0x199/0x2b0 |
| [ 2616.095934] RIP: 0010:debug_print_object+0x199/0x2b0 |
| [ 2616.191533] Call Trace: |
| [ 2616.194265] <IRQ> |
| [ 2616.202068] debug_check_no_obj_freed+0x25e/0x3f0 |
| [ 2616.207336] slab_free_freelist_hook+0xeb/0x140 |
| [ 2616.220971] kfree+0xd6/0x2c0 |
| [ 2616.224293] rcu_do_batch+0x3bd/0xc70 |
| [ 2616.243096] rcu_core+0x8b9/0xd00 |
| [ 2616.256065] __do_softirq+0x23d/0xacd |
| [ 2616.260166] irq_exit+0x236/0x2a0 |
| [ 2616.263879] smp_apic_timer_interrupt+0x18d/0x620 |
| [ 2616.269138] apic_timer_interrupt+0xf/0x20 |
| [ 2616.273711] </IRQ> |
| |
| This is because it holds asoc when transport->proto_unreach_timer starts |
| and puts asoc when the timer stops, and without holding transport the |
| transport could be freed when the timer is still running. |
| |
| So fix it by holding/putting transport instead for proto_unreach_timer |
| in transport, just like other timers in transport. |
| |
| v1->v2: |
| - Also use sctp_transport_put() for the "out_unlock:" path in |
| sctp_generate_proto_unreach_event(), as Marcelo noticed. |
| |
| Fixes: 50b5d6ad6382 ("sctp: Fix a race between ICMP protocol unreachable and connect()") |
| Reported-by: Hangbin Liu <liuhangbin@gmail.com> |
| Signed-off-by: Xin Long <lucien.xin@gmail.com> |
| Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> |
| Link: https://lore.kernel.org/r/102788809b554958b13b95d33440f5448113b8d6.1605331373.git.lucien.xin@gmail.com |
| Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/sctp/input.c | 4 ++-- |
| net/sctp/sm_sideeffect.c | 4 ++-- |
| net/sctp/transport.c | 2 +- |
| 3 files changed, 5 insertions(+), 5 deletions(-) |
| |
| --- a/net/sctp/input.c |
| +++ b/net/sctp/input.c |
| @@ -461,7 +461,7 @@ void sctp_icmp_proto_unreachable(struct |
| else { |
| if (!mod_timer(&t->proto_unreach_timer, |
| jiffies + (HZ/20))) |
| - sctp_association_hold(asoc); |
| + sctp_transport_hold(t); |
| } |
| } else { |
| struct net *net = sock_net(sk); |
| @@ -470,7 +470,7 @@ void sctp_icmp_proto_unreachable(struct |
| "encountered!\n", __func__); |
| |
| if (del_timer(&t->proto_unreach_timer)) |
| - sctp_association_put(asoc); |
| + sctp_transport_put(t); |
| |
| sctp_do_sm(net, SCTP_EVENT_T_OTHER, |
| SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), |
| --- a/net/sctp/sm_sideeffect.c |
| +++ b/net/sctp/sm_sideeffect.c |
| @@ -434,7 +434,7 @@ void sctp_generate_proto_unreach_event(s |
| /* Try again later. */ |
| if (!mod_timer(&transport->proto_unreach_timer, |
| jiffies + (HZ/20))) |
| - sctp_association_hold(asoc); |
| + sctp_transport_hold(transport); |
| goto out_unlock; |
| } |
| |
| @@ -450,7 +450,7 @@ void sctp_generate_proto_unreach_event(s |
| |
| out_unlock: |
| bh_unlock_sock(sk); |
| - sctp_association_put(asoc); |
| + sctp_transport_put(transport); |
| } |
| |
| /* Handle the timeout of the RE-CONFIG timer. */ |
| --- a/net/sctp/transport.c |
| +++ b/net/sctp/transport.c |
| @@ -148,7 +148,7 @@ void sctp_transport_free(struct sctp_tra |
| |
| /* Delete the ICMP proto unreachable timer if it's active. */ |
| if (del_timer(&transport->proto_unreach_timer)) |
| - sctp_association_put(transport->asoc); |
| + sctp_transport_put(transport); |
| |
| sctp_transport_put(transport); |
| } |