tg import create t/mptcp-fix-sleep-in-atomic-at-close-time

.topmsg

@@ -1,4 +1,50 @@
-From: Matthieu Baerts <matthieu.baerts@tessares.net>
-Subject: [PATCH] t/mptcp-fix-sleep-in-atomic-at-close-time
+From: Paolo Abeni <pabeni@redhat.com>
+Subject: [PATCH] mptcp: fix sleep in atomic at close time
 
-Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
+Matt reported a splat at msk close time:
+
+    BUG: sleeping function called from invalid context at net/mptcp/protocol.c:2877
+    in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 155, name: packetdrill
+    preempt_count: 201, expected: 0
+    RCU nest depth: 0, expected: 0
+    4 locks held by packetdrill/155:
+    #0: ffff888001536990 (&sb->s_type->i_mutex_key#6){+.+.}-{3:3}, at: __sock_release (net/socket.c:650)
+    #1: ffff88800b498130 (sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_close (net/mptcp/protocol.c:2973)
+    #2: ffff88800b49a130 (sk_lock-AF_INET/1){+.+.}-{0:0}, at: __mptcp_close_ssk (net/mptcp/protocol.c:2363)
+    #3: ffff88800b49a0b0 (slock-AF_INET){+...}-{2:2}, at: __lock_sock_fast (include/net/sock.h:1820)
+    Preemption disabled at:
+    0x0
+    CPU: 1 PID: 155 Comm: packetdrill Not tainted 6.1.0-rc5 #365
+    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
+    Call Trace:
+    <TASK>
+    dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4))
+    __might_resched.cold (kernel/sched/core.c:9891)
+    __mptcp_destroy_sock (include/linux/kernel.h:110)
+    __mptcp_close (net/mptcp/protocol.c:2959)
+    mptcp_subflow_queue_clean (include/net/sock.h:1777)
+    __mptcp_close_ssk (net/mptcp/protocol.c:2363)
+    mptcp_destroy_common (net/mptcp/protocol.c:3170)
+    mptcp_destroy (include/net/sock.h:1495)
+    __mptcp_destroy_sock (net/mptcp/protocol.c:2886)
+    __mptcp_close (net/mptcp/protocol.c:2959)
+    mptcp_close (net/mptcp/protocol.c:2974)
+    inet_release (net/ipv4/af_inet.c:432)
+    __sock_release (net/socket.c:651)
+    sock_close (net/socket.c:1367)
+    __fput (fs/file_table.c:320)
+    task_work_run (kernel/task_work.c:181 (discriminator 1))
+    exit_to_user_mode_prepare (include/linux/resume_user_mode.h:49)
+    syscall_exit_to_user_mode (kernel/entry/common.c:130)
+    do_syscall_64 (arch/x86/entry/common.c:87)
+    entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
+
+We can't call mptcp_close under the 'fast' socket lock variant, replace
+it with a sock_lock_nested() as the relevant code is already under the
+listening msk socket lock protection.
+
+Reported-by: Matthieu Baerts <matthieu.baerts@tessares.net>
+Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/316
+Fixes: 30e51b923e43 ("mptcp: fix unreleased socket in accept queue")
+Signed-off-by: Paolo Abeni <pabeni@redhat.com>
+Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>