Date:	Fri, 22 Feb 2013 14:33:20 +0800
From:	xtu4 <xiaobing.tu@...el.com>
To:	gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
	chao.bi@...el.com, faouazx.tenoutit@...el.com,
	olivierx.stoltz-douchet@...el.com, yanmin.zhang@...el.com
Subject: [patch] hsi : Avoid race condition between HSI controller and HSI
 client when system restart and power down

Avoid race condition between HSI controller and HSI client when system 
restart and power down


hsi_isr_tasklet disabled in HSI_controller exit, but before HSI 
controller exit,
HSI client will cleanup, this cleanup will destroy the spinlock used by the
hsi_isr_tasklet,so if after HSI client cleanup, there still such tasklet 
running,
issue will happend. here is the issue stack as below.
hsi-ctrl: WAKEf514b000: f9a800e5 00000010 60000006 00000000 013f5bf9 
582bf9b8 3d565244
hsi-dlp: TTY device close request (mmgr, 133)
hsi-dlp: port shutdown request
mdm_ctrl: Unexpected RESET_OUT 0x0
BUG: spinlock bad magic on CPU#3, zygote/137
lock: f53a0fbc, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
Pid: 137, comm: zygote Tainted: G         C  3.0.34-141888-g9e0a6fb #1
Call Trace:
  [<c185c92c>] ? printk+0x1d/0x1f
  [<c1860826>] spin_bug+0xa4/0xac
  [<c14a5d6d>] do_raw_spin_lock+0x7d/0x170
  [<c1866c86>] ? _raw_spin_unlock_irqrestore+0x26/0x50
  [<c1866afc>] _raw_spin_lock_irqsave+0x2c/0x40
  [<c12325d0>] complete+0x20/0x60
  [<c1866c86>] ? _raw_spin_unlock_irqrestore+0x26/0x50
  [<c1576ff9>] dlp_ctrl_complete_tx+0x29/0x40
  [<c1570164>] hsi_isr_tasklet+0x394/0x11a0
  [<c12709f5>] ? sched_clock_cpu+0xe5/0x150
  [<c1251a39>] tasklet_hi_action+0x59/0x120
  [<c12500d8>] ? it_real_fn+0x18/0xb0
  [<c12522ab>] __do_softirq+0x9b/0x220
  [<c1252210>] ? remote_softirq_receive+0x110/0x110
Change-Id: I6a0ca0c14409bfc4cd7a2767a4f203c171ece007
Signed-off-by: xiaobing tu <xiaobing.tu@...el.com>
Signed-off-by: chao bi <chao.bi@...el.com>
---
  drivers/hsi/clients/dlp_ctrl.c  |    4 ++++
  drivers/hsi/clients/dlp_flash.c |    5 ++++-
  drivers/hsi/clients/dlp_net.c   |    4 ++++
  drivers/hsi/clients/dlp_trace.c |    1 -
  drivers/hsi/clients/dlp_tty.c   |    5 ++++-
  5 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/hsi/clients/dlp_ctrl.c b/drivers/hsi/clients/dlp_ctrl.c
index b09f9e6..e980f0c 100644
--- a/drivers/hsi/clients/dlp_ctrl.c
+++ b/drivers/hsi/clients/dlp_ctrl.c
@@ -394,6 +394,8 @@ static void dlp_ctrl_complete_tx(struct hsi_msg *msg)
      struct dlp_command *dlp_cmd = msg->context;
      struct dlp_channel *ch_ctx = dlp_cmd->channel;

+    if (dlp_drv.channels[DLP_CHANNEL_CTRL] == NULL)
+        return;
      dlp_cmd->status = (msg->status == HSI_STATUS_COMPLETED) ? 0 : -EIO;

      /* Command done, notify the sender */
@@ -433,6 +435,8 @@ static void dlp_ctrl_complete_rx(struct hsi_msg *msg)
      unsigned long flags;
      int hsi_channel, elp_channel, ret, response, msg_complete, state;

+    if (dlp_drv.channels[DLP_CHANNEL_CTRL] == NULL)
+        return;
      /* Copy the reponse */
      memcpy(&params,
             sg_virt(msg->sgt.sgl), sizeof(struct dlp_command_params));
diff --git a/drivers/hsi/clients/dlp_flash.c 
b/drivers/hsi/clients/dlp_flash.c
index 885b73a..b333d74 100644
--- a/drivers/hsi/clients/dlp_flash.c
+++ b/drivers/hsi/clients/dlp_flash.c
@@ -42,7 +42,6 @@
   */
  #define DLP_FLASH_NB_RX_MSG 10

-
  /*
   * struct flashing_driver - HSI Modem flashing driver protocol
   *
@@ -259,6 +258,8 @@ static struct hsi_msg *dlp_boot_rx_dequeue(struct 
dlp_channel *ch_ctx)
  */
  static void dlp_flash_complete_tx(struct hsi_msg *msg)
  {
+    if (dlp_drv.channels[DLP_CHANNEL_FLASH] == NULL)
+        return;
      /* Delete the received msg */
      dlp_pdu_free(msg, -1);
  }
@@ -274,6 +275,8 @@ static void dlp_flash_complete_rx(struct hsi_msg *msg)
      struct dlp_flash_ctx *flash_ctx = ch_ctx->ch_data;
      int ret;

+    if (dlp_drv.channels[DLP_CHANNEL_FLASH] == NULL)
+        return;
      if (msg->status != HSI_STATUS_COMPLETED) {
          pr_err(DRVNAME ": Invalid msg status: %d (ignored)\n",
                  msg->status);
diff --git a/drivers/hsi/clients/dlp_net.c b/drivers/hsi/clients/dlp_net.c
index f3ca817..0c3e672 100644
--- a/drivers/hsi/clients/dlp_net.c
+++ b/drivers/hsi/clients/dlp_net.c
@@ -158,6 +158,8 @@ static void dlp_net_complete_tx(struct hsi_msg *pdu)
      struct dlp_net_context *net_ctx = ch_ctx->ch_data;
      struct dlp_xfer_ctx *xfer_ctx = &ch_ctx->tx;

+    if (dlp_drv.channels[ch_ctx->hsi_channel] == NULL)
+            return;
      /* TX done, free the skb */
      dev_kfree_skb(msg_param->skb);

@@ -197,6 +199,8 @@ static void dlp_net_complete_rx(struct hsi_msg *pdu)
      unsigned int *ptr;
      unsigned long flags;

+    if (dlp_drv.channels[ch_ctx->hsi_channel] == NULL)
+        return;
      /* Pop the CTRL queue */
      write_lock_irqsave(&xfer_ctx->lock, flags);
      dlp_hsi_controller_pop(xfer_ctx);
diff --git a/drivers/hsi/clients/dlp_trace.c 
b/drivers/hsi/clients/dlp_trace.c
index fa91985..0067798 100644
--- a/drivers/hsi/clients/dlp_trace.c
+++ b/drivers/hsi/clients/dlp_trace.c
@@ -84,7 +84,6 @@ static unsigned int log_dropped_data;
  module_param_named(log_dropped_data, log_dropped_data, int, S_IRUGO | 
S_IWUSR);
  #endif

-
  /*
   *
   */
diff --git a/drivers/hsi/clients/dlp_tty.c b/drivers/hsi/clients/dlp_tty.c
index 7774484..47f6697 100644
--- a/drivers/hsi/clients/dlp_tty.c
+++ b/drivers/hsi/clients/dlp_tty.c
@@ -68,7 +68,6 @@ struct dlp_tty_context {
      struct work_struct    do_tty_forward;
  };

-
  /**
   * Push as many RX PDUs  as possible to the controller FIFO
   *
@@ -337,6 +336,8 @@ static void dlp_tty_complete_tx(struct hsi_msg *pdu)
      int wakeup, avail, pending;
      unsigned long flags;

+    if (dlp_drv.channels[DLP_CHANNEL_TTY] == NULL)
+        return;
      /* Recycle or Free the pdu */
      write_lock_irqsave(&xfer_ctx->lock, flags);
      dlp_pdu_delete(xfer_ctx, pdu);
@@ -375,6 +376,8 @@ static void dlp_tty_complete_rx(struct hsi_msg *pdu)
      unsigned long flags;
      int ret;

+    if (dlp_drv.channels[DLP_CHANNEL_TTY] == NULL)
+        return;
      /* Check the received PDU header & seq_num */
      ret = dlp_pdu_header_check(xfer_ctx, pdu);
      if (ret == -EINVAL) {
-- 
1.7.6

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