> On Sep 26, 2023, at 5:03 PM, Anna Schumaker <anna@xxxxxxxxxx> wrote: > > From: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx> > > Otherwise we run the risk of having the lower_xprt freed from underneath > us, causing an oops that looks like this: > > [ 224.150698] BUG: kernel NULL pointer dereference, address: 0000000000000018 > [ 224.150951] #PF: supervisor read access in kernel mode > [ 224.151117] #PF: error_code(0x0000) - not-present page > [ 224.151278] PGD 0 P4D 0 > [ 224.151361] Oops: 0000 [#1] PREEMPT SMP NOPTI > [ 224.151499] CPU: 2 PID: 99 Comm: kworker/u10:6 Not tainted 6.6.0-rc3-g6465e260f487 #41264 a00b0960990fb7bc6d6a330ee03588b67f08a47b > [ 224.151977] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 2/2/2022 > [ 224.152216] Workqueue: xprtiod xs_tcp_tls_setup_socket [sunrpc] > [ 224.152434] RIP: 0010:xs_tcp_tls_setup_socket+0x3cc/0x7e0 [sunrpc] > [ 224.152643] Code: 00 00 48 8b 7c 24 08 e9 f3 01 00 00 48 83 7b c0 00 0f 85 d2 01 00 00 49 8d 84 24 f8 05 00 00 48 89 44 24 10 48 8b 00 48 89 c5 <4c> 8b 68 18 66 41 83 3f 0a 75 71 45 31 ff 4c 89 ef 31 f6 e8 5c 76 > [ 224.153246] RSP: 0018:ffffb00ec060fd18 EFLAGS: 00010246 > [ 224.153427] RAX: 0000000000000000 RBX: ffff8c06c2e53e40 RCX: 0000000000000001 > [ 224.153652] RDX: ffff8c073bca2408 RSI: 0000000000000282 RDI: ffff8c06c259ee00 > [ 224.153868] RBP: 0000000000000000 R08: ffffffff9da55aa0 R09: 0000000000000001 > [ 224.154084] R10: 00000034306c30f1 R11: 0000000000000002 R12: ffff8c06c2e51800 > [ 224.154300] R13: ffff8c06c355d400 R14: 0000000004208160 R15: ffff8c06c2e53820 > [ 224.154521] FS: 0000000000000000(0000) GS:ffff8c073bd00000(0000) knlGS:0000000000000000 > [ 224.154763] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 224.154940] CR2: 0000000000000018 CR3: 0000000062c1e000 CR4: 0000000000750ee0 > [ 224.155157] PKRU: 55555554 > [ 224.155244] Call Trace: > [ 224.155325] <TASK> > [ 224.155395] ? __die_body+0x68/0xb0 > [ 224.155507] ? page_fault_oops+0x34c/0x3a0 > [ 224.155635] ? _raw_spin_unlock_irqrestore+0xe/0x40 > [ 224.155793] ? exc_page_fault+0x7a/0x1b0 > [ 224.155916] ? asm_exc_page_fault+0x26/0x30 > [ 224.156047] ? xs_tcp_tls_setup_socket+0x3cc/0x7e0 [sunrpc ae3a15912ae37fd51dafbdbc2dbd069117f8f5c8] > [ 224.156367] ? xs_tcp_tls_setup_socket+0x2fe/0x7e0 [sunrpc ae3a15912ae37fd51dafbdbc2dbd069117f8f5c8] > [ 224.156697] ? __pfx_xs_tls_handshake_done+0x10/0x10 [sunrpc ae3a15912ae37fd51dafbdbc2dbd069117f8f5c8] > [ 224.157013] process_scheduled_works+0x24e/0x450 > [ 224.157158] worker_thread+0x21c/0x2d0 > [ 224.157275] ? __pfx_worker_thread+0x10/0x10 > [ 224.157409] kthread+0xe8/0x110 > [ 224.157510] ? __pfx_kthread+0x10/0x10 > [ 224.157628] ret_from_fork+0x37/0x50 > [ 224.157741] ? __pfx_kthread+0x10/0x10 > [ 224.157859] ret_from_fork_asm+0x1b/0x30 > [ 224.157983] </TASK> > > Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx> I don't have any quibbles with this. Thanks! Reviewed-by: Chuck Lever <chuck.lever@xxxxxxxxxx <mailto:chuck.lever@xxxxxxxxxx>> > --- > net/sunrpc/xprtsock.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c > index 71cd916e384f..a15bf2ede89b 100644 > --- a/net/sunrpc/xprtsock.c > +++ b/net/sunrpc/xprtsock.c > @@ -2672,6 +2672,10 @@ static void xs_tcp_tls_setup_socket(struct work_struct *work) > rcu_read_lock(); > lower_xprt = rcu_dereference(lower_clnt->cl_xprt); > rcu_read_unlock(); > + > + if (wait_on_bit_lock(&lower_xprt->state, XPRT_LOCKED, TASK_KILLABLE)) > + goto out_unlock; > + > status = xs_tls_handshake_sync(lower_xprt, &upper_xprt->xprtsec); > if (status) { > trace_rpc_tls_not_started(upper_clnt, upper_xprt); > @@ -2681,6 +2685,7 @@ static void xs_tcp_tls_setup_socket(struct work_struct *work) > status = xs_tcp_tls_finish_connecting(lower_xprt, upper_transport); > if (status) > goto out_close; > + xprt_release_write(lower_xprt, NULL); > > trace_rpc_socket_connect(upper_xprt, upper_transport->sock, 0); > if (!xprt_test_and_set_connected(upper_xprt)) { > @@ -2702,6 +2707,7 @@ static void xs_tcp_tls_setup_socket(struct work_struct *work) > return; > > out_close: > + xprt_release_write(lower_xprt, NULL); > rpc_shutdown_client(lower_clnt); > > /* xprt_force_disconnect() wakes tasks with a fixed tk_status code. > -- > 2.42.0 > -- Chuck Lever
