* [PATCH 1/3 V2] b43: Fix lockdep splat
2014-01-12 21:11 [PATCH 0/3 V2] iFixes for b43 and b43legacy Larry Finger
@ 2014-01-12 21:11 ` Larry Finger
2014-01-12 21:11 ` [PATCH 2/3 V2] b43: Fix unload oops if firmware is not available Larry Finger
2014-01-12 21:11 ` [PATCH 3/3 V2] b43legacy: " Larry Finger
2 siblings, 0 replies; 4+ messages in thread
From: Larry Finger @ 2014-01-12 21:11 UTC (permalink / raw)
To: linville; +Cc: linux-wireless, Larry Finger, netdev, Stable
In https://bugzilla.kernel.org/show_bug.cgi?id=67561, a locking dependency is reported
when b43 is used with hostapd, and rfkill is used to kill the radio output.
The lockdep splat (in part) is as follows:
======================================================
[ INFO: possible circular locking dependency detected ]
3.12.0 #1 Not tainted
-------------------------------------------------------
rfkill/10040 is trying to acquire lock:
(rtnl_mutex){+.+.+.}, at: [<ffffffff8146f282>] rtnl_lock+0x12/0x20
but task is already holding lock:
(rfkill_global_mutex){+.+.+.}, at: [<ffffffffa04832ca>] rfkill_fop_write+0x6a/0x170 [rfkill]
--snip--
Chain exists of:
rtnl_mutex --> misc_mtx --> rfkill_global_mutex
The fix is to move the initialization of the hardware random number generator
outside the code range covered by the rtnl_mutex.
Reported-by: yury <urykhy@gmail.com>
Tested-by: yury <urykhy@gmail.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Stable <stable@vger.kernel.org>
---
V2 is identical to V1.
drivers/net/wireless/b43/main.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index ccd24f0a..86b2030 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -2424,6 +2424,7 @@ error:
static int b43_one_core_attach(struct b43_bus_dev *dev, struct b43_wl *wl);
static void b43_one_core_detach(struct b43_bus_dev *dev);
+static int b43_rng_init(struct b43_wl *wl);
static void b43_request_firmware(struct work_struct *work)
{
@@ -2475,6 +2476,10 @@ start_ieee80211:
goto err_one_core_detach;
wl->hw_registred = true;
b43_leds_register(wl->current_dev);
+
+ /* Register HW RNG driver */
+ b43_rng_init(wl);
+
goto out;
err_one_core_detach:
@@ -4636,9 +4641,6 @@ static void b43_wireless_core_exit(struct b43_wldev *dev)
if (!dev || b43_status(dev) != B43_STAT_INITIALIZED)
return;
- /* Unregister HW RNG driver */
- b43_rng_exit(dev->wl);
-
b43_set_status(dev, B43_STAT_UNINIT);
/* Stop the microcode PSM. */
@@ -4795,9 +4797,6 @@ static int b43_wireless_core_init(struct b43_wldev *dev)
b43_set_status(dev, B43_STAT_INITIALIZED);
- /* Register HW RNG driver */
- b43_rng_init(dev->wl);
-
out:
return err;
@@ -5464,6 +5463,9 @@ static void b43_bcma_remove(struct bcma_device *core)
b43_one_core_detach(wldev->dev);
+ /* Unregister HW RNG driver */
+ b43_rng_exit(wl);
+
b43_leds_unregister(wl);
ieee80211_free_hw(wl->hw);
@@ -5541,6 +5543,9 @@ static void b43_ssb_remove(struct ssb_device *sdev)
b43_one_core_detach(dev);
+ /* Unregister HW RNG driver */
+ b43_rng_exit(wl);
+
if (list_empty(&wl->devlist)) {
b43_leds_unregister(wl);
/* Last core on the chip unregistered.
--
1.8.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 2/3 V2] b43: Fix unload oops if firmware is not available
2014-01-12 21:11 [PATCH 0/3 V2] iFixes for b43 and b43legacy Larry Finger
2014-01-12 21:11 ` [PATCH 1/3 V2] b43: Fix lockdep splat Larry Finger
@ 2014-01-12 21:11 ` Larry Finger
2014-01-12 21:11 ` [PATCH 3/3 V2] b43legacy: " Larry Finger
2 siblings, 0 replies; 4+ messages in thread
From: Larry Finger @ 2014-01-12 21:11 UTC (permalink / raw)
To: linville; +Cc: linux-wireless, Larry Finger, netdev, Stable
The asyncronous firmware load uses a completion struct to hold firmware
processing until the user-space routines are up and running. There is.
however, a problem in that the waiter is nevered canceled during teardown.
As a result, unloading the driver when firmware is not available causes an oops.
To be able to access the completion structure at teardown, it had to be moved
into the b43_wldev structure.
This patch also fixes a typo in a comment.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Stable <stable@vger.kernel.org>
---
V2 - Addresses the comments of Ben Hutchings and removes the race condition.
drivers/net/wireless/b43/b43.h | 4 ++--
drivers/net/wireless/b43/main.c | 10 +++++-----
2 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/net/wireless/b43/b43.h b/drivers/net/wireless/b43/b43.h
index 7f3d461..54376fd 100644
--- a/drivers/net/wireless/b43/b43.h
+++ b/drivers/net/wireless/b43/b43.h
@@ -731,8 +731,6 @@ enum b43_firmware_file_type {
struct b43_request_fw_context {
/* The device we are requesting the fw for. */
struct b43_wldev *dev;
- /* a completion event structure needed if this call is asynchronous */
- struct completion fw_load_complete;
/* a pointer to the firmware object */
const struct firmware *blob;
/* The type of firmware to request. */
@@ -809,6 +807,8 @@ enum {
struct b43_wldev {
struct b43_bus_dev *dev;
struct b43_wl *wl;
+ /* a completion event structure needed if this call is asynchronous */
+ struct completion fw_load_complete;
/* The device initialization status.
* Use b43_status() to query. */
diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index 86b2030..c75237e 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -2070,6 +2070,7 @@ void b43_do_release_fw(struct b43_firmware_file *fw)
static void b43_release_firmware(struct b43_wldev *dev)
{
+ complete(&dev->fw_load_complete);
b43_do_release_fw(&dev->fw.ucode);
b43_do_release_fw(&dev->fw.pcm);
b43_do_release_fw(&dev->fw.initvals);
@@ -2095,7 +2096,7 @@ static void b43_fw_cb(const struct firmware *firmware, void *context)
struct b43_request_fw_context *ctx = context;
ctx->blob = firmware;
- complete(&ctx->fw_load_complete);
+ complete(&ctx->dev->fw_load_complete);
}
int b43_do_request_fw(struct b43_request_fw_context *ctx,
@@ -2142,7 +2143,7 @@ int b43_do_request_fw(struct b43_request_fw_context *ctx,
}
if (async) {
/* do this part asynchronously */
- init_completion(&ctx->fw_load_complete);
+ init_completion(&ctx->dev->fw_load_complete);
err = request_firmware_nowait(THIS_MODULE, 1, ctx->fwname,
ctx->dev->dev->dev, GFP_KERNEL,
ctx, b43_fw_cb);
@@ -2150,12 +2151,11 @@ int b43_do_request_fw(struct b43_request_fw_context *ctx,
pr_err("Unable to load firmware\n");
return err;
}
- /* stall here until fw ready */
- wait_for_completion(&ctx->fw_load_complete);
+ wait_for_completion(&ctx->dev->fw_load_complete);
if (ctx->blob)
goto fw_ready;
/* On some ARM systems, the async request will fail, but the next sync
- * request works. For this reason, we dall through here
+ * request works. For this reason, we fall through here
*/
}
err = request_firmware(&ctx->blob, ctx->fwname,
--
1.8.4
^ permalink raw reply related [flat|nested] 4+ messages in thread