[PATCH 3.18 01/22] dccp: purge write queue in dccp_destroy_sock()

Greg Kroah-Hartman
2017-08-28T08:16:12Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 7749d4ff88d31b0be17c8683143135adaaadc6a7 ]

syzkaller reported that DCCP could have a non empty
write queue at dismantle time.

WARNING: CPU: 1 PID: 2953 at net/core/stream.c:199 sk_stream_kill_queues+0x3ce/0x520 net/core/stream.c:199
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 2953 Comm: syz-executor0 Not tainted 4.13.0-rc4+ #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:16 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:52
panic+0x1e4/0x417 kernel/panic.c:180
__warn+0x1c4/0x1d9 kernel/panic.c:541
report_bug+0x211/0x2d0 lib/bug.c:183
fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:190
do_trap_no_signal arch/x86/kernel/traps.c:224 [inline]
do_trap+0x260/0x390 arch/x86/kernel/traps.c:273
do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:310
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:323
invalid_op+0x1e/0x30 arch/x86/entry/entry_64.S:846
RIP: 0010:sk_stream_kill_queues+0x3ce/0x520 net/core/stream.c:199
RSP: 0018:ffff8801d182f108 EFLAGS: 00010297
RAX: ffff8801d1144140 RBX: ffff8801d13cb280 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff85137b00 RDI: ffff8801d13cb280
RBP: ffff8801d182f148 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d13cb4d0
R13: ffff8801d13cb3b8 R14: ffff8801d13cb300 R15: ffff8801d13cb3b8
inet_csk_destroy_sock+0x175/0x3f0 net/ipv4/inet_connection_sock.c:835
dccp_close+0x84d/0xc10 net/dccp/proto.c:1067
inet_release+0xed/0x1c0 net/ipv4/af_inet.c:425
sock_release+0x8d/0x1e0 net/socket.c:597
sock_close+0x16/0x20 net/socket.c:1126
__fput+0x327/0x7e0 fs/file_table.c:210
____fput+0x15/0x20 fs/file_table.c:246
task_work_run+0x18a/0x260 kernel/task_work.c:116
exit_task_work include/linux/task_work.h:21 [inline]
do_exit+0xa32/0x1b10 kernel/exit.c:865
do_group_exit+0x149/0x400 kernel/exit.c:969
get_signal+0x7e8/0x17e0 kernel/signal.c:2330
do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:808
exit_to_usermode_loop+0x21c/0x2d0 arch/x86/entry/common.c:157
prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
syscall_return_slowpath+0x3a7/0x450 arch/x86/entry/common.c:263

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/dccp/proto.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -201,10 +201,7 @@ void dccp_destroy_sock(struct sock *sk)
{
struct dccp_sock *dp = dccp_sk(sk);

- /*
- * DCCP doesn't use sk_write_queue, just sk_send_head
- * for retransmissions
- */
+ __skb_queue_purge(&sk->sk_write_queue);
if (sk->sk_send_head != NULL) {
kfree_skb(sk->sk_send_head);
sk->sk_send_head = NULL;