[PATCH 4.20 164/171] bpf: Stop the psock parser before canceling its work

Greg Kroah-Hartman
2019-03-12T17:59:28Z

From: Jakub Sitnicki <jakub@cloudflare.com>

commit e8e3437762ad938880dd48a3c52d702e7cf3c124 upstream.

We might have never enabled (started) the psock's parser, in which case it
will not get stopped when destroying the psock. This leads to a warning
when trying to cancel parser's work from psock's deferred destructor:

[ 405.325769] WARNING: CPU: 1 PID: 3216 at net/strparser/strparser.c:526 strp_done+0x3c/0x40
[ 405.326712] Modules linked in: [last unloaded: test_bpf]
[ 405.327359] CPU: 1 PID: 3216 Comm: kworker/1:164 Tainted: G W 5.0.0 #42
[ 405.328294] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20180531_142017-buildhw-08.phx2.fedoraproject.org-1.fc28 04/01/2014
[ 405.329712] Workqueue: events sk_psock_destroy_deferred
[ 405.330254] RIP: 0010:strp_done+0x3c/0x40
[ 405.330706] Code: 28 e8 b8 d5 6b ff 48 8d bb 80 00 00 00 e8 9c d5 6b ff 48 8b 7b 18 48 85 ff 74 0d e8 1e a5 e8 ff 48 c7 43 18 00 00 00 00 5b c3 <0f> 0b eb cf 66 66 66 66 90 55 89 f5 53 48 89 fb 48 83 c7 28 e8 0b
[ 405.332862] RSP: 0018:ffffc900026bbe50 EFLAGS: 00010246
[ 405.333482] RAX: ffffffff819323e0 RBX: ffff88812cb83640 RCX: ffff88812cb829e8
[ 405.334228] RDX: 0000000000000001 RSI: ffff88812cb837e8 RDI: ffff88812cb83640
[ 405.335366] RBP: ffff88813fd22680 R08: 0000000000000000 R09: 000073746e657665
[ 405.336472] R10: 8080808080808080 R11: 0000000000000001 R12: ffff88812cb83600
[ 405.337760] R13: 0000000000000000 R14: ffff88811f401780 R15: ffff88812cb837e8
[ 405.338777] FS: 0000000000000000(0000) GS:ffff88813fd00000(0000) knlGS:0000000000000000
[ 405.339903] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 405.340821] CR2: 00007fb11489a6b8 CR3: 000000012d4d6000 CR4: 00000000000406e0
[ 405.341981] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 405.343131] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 405.344415] Call Trace:
[ 405.344821] sk_psock_destroy_deferred+0x23/0x1b0
[ 405.345585] process_one_work+0x1ae/0x3e0
[ 405.346110] worker_thread+0x3c/0x3b0
[ 405.346576] ? pwq_unbound_release_workfn+0xd0/0xd0
[ 405.347187] kthread+0x11d/0x140
[ 405.347601] ? __kthread_parkme+0x80/0x80
[ 405.348108] ret_from_fork+0x35/0x40
[ 405.348566] ---[ end trace a4a3af4026a327d4 ]---

Stop psock's parser just before canceling its work.

Fixes: 1d79895aef18 ("sk_msg: Always cancel strp work before freeing the psock")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/core/skmsg.c | 1 +
1 file changed, 1 insertion(+)

--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -545,6 +545,7 @@ static void sk_psock_destroy_deferred(st
struct sk_psock *psock = container_of(gc, struct sk_psock, gc);

/* No sk_callback_lock since already detached. */
+ strp_stop(&psock->parser.strp);
strp_done(&psock->parser.strp);

cancel_work_sync(&psock->work);