thunderbolt: Fix NULL dereference in tb_remove_work()grafted

There is a slight race between tb_remove_work() and tb_domain_remove()
which leads to dereferencing a NULL tb->root_switch pointer inside
tb_free_unplugged_xdomains():

        Thread A                            Thread B

  tb_remove_work()
                                    tb_domain_remove()
                                      mutex_lock(&tb->lock)
                                      tb_stop()
                                        /* doesn't cancel a running callback */
                                        cancel_delayed_work(&tcm->remove_work)
                                        ...
                                        tb_switch_remove(tb->root_switch)
                                        tb->root_switch = NULL
                                      mutex_unlock(&tb->lock)
    mutex_lock(&tb->lock)
    ...
    /* without checking ->root_switch */
    tb_free_unplugged_xdomains(tb->root_switch)
    mutex_unlock(&tb->lock)

Commit a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without
holding tb->lock") doesn't seem right to move tb_free_unplugged_xdomains()
out of the &tb->lock section and the check for tb->root_switch, in
particular.  It states:

  For this reason separate removing the XDomain from the topology data
  structures (where we need the lock) from unregistering the device from
  the bus (where remove callbacks of the drivers are being called).

tb_free_unplugged_xdomains() belongs to the former group of functions
requiring the lock.  And it also calls tb_xdomain_remove() which should
only be called with &tb->lock held.

Found by Linux Verification Center (linuxtesting.org) with Svace static
analysis tool.

Fixes: a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without holding tb->lock")
Cc: stable@vger.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/include/sound/sof/dai-imx.h b/include/sound/sof/dai-imx.h
new file mode 100644
index 000000000..6bc987bd4
--- /dev/null
+++ b/include/sound/sof/dai-imx.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) */
+/*
+ * Copyright 2019 NXP
+ *
+ * Author: Daniel Baluta <daniel.baluta@nxp.com>
+ */
+
+#ifndef __INCLUDE_SOUND_SOF_DAI_IMX_H__
+#define __INCLUDE_SOUND_SOF_DAI_IMX_H__
+
+#include <sound/sof/header.h>
+
+/* ESAI Configuration Request - SOF_IPC_DAI_ESAI_CONFIG */
+struct sof_ipc_dai_esai_params {
+	struct sof_ipc_hdr hdr;
+
+	/* MCLK */
+	uint16_t reserved1;
+	uint16_t mclk_id;
+	uint32_t mclk_direction;
+
+	uint32_t mclk_rate;	/* MCLK frequency in Hz */
+	uint32_t fsync_rate;	/* FSYNC frequency in Hz */
+	uint32_t bclk_rate;	/* BCLK frequency in Hz */
+
+	/* TDM */
+	uint32_t tdm_slots;
+	uint32_t rx_slots;
+	uint32_t tx_slots;
+	uint16_t tdm_slot_width;
+	uint16_t reserved2;	/* alignment */
+} __packed;
+
+/* SAI Configuration Request - SOF_IPC_DAI_SAI_CONFIG */
+struct sof_ipc_dai_sai_params {
+	struct sof_ipc_hdr hdr;
+
+	/* MCLK */
+	uint16_t reserved1;
+	uint16_t mclk_id;
+	uint32_t mclk_direction;
+
+	uint32_t mclk_rate;	/* MCLK frequency in Hz */
+	uint32_t fsync_rate;	/* FSYNC frequency in Hz */
+	uint32_t bclk_rate;	/* BCLK frequency in Hz */
+
+	/* TDM */
+	uint32_t tdm_slots;
+	uint32_t rx_slots;
+	uint32_t tx_slots;
+	uint16_t tdm_slot_width;
+	uint16_t reserved2;	/* alignment */
+} __packed;
+
+/* MICFIL Configuration Request - SOF_IPC_DAI_MICFIL_CONFIG */
+struct sof_ipc_dai_micfil_params {
+	uint32_t pdm_rate;
+	uint32_t pdm_ch;
+} __packed;
+
+#endif