[ Upstream commit a9fd0953fa4a62887306be28641b4b0809f3b2fd ]
Leaving dev_init_lock mutex locked in probe causes BUG and a WARNING when kernel is compiled with CONFIG_PROVE_LOCKING. Convert mutex to completion which silences those warnings and improves code readability.
Fix below errors when connecting the USB WiFi dongle:
brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43143 for chip BCM43143/2 BUG: workqueue leaked lock or atomic: kworker/0:2/0x00000000/434 last function: hub_event 1 lock held by kworker/0:2/434: #0: 18d5dcdf (&devinfo->dev_init_lock){+.+.}, at: brcmf_usb_probe+0x78/0x550 [brcmfmac] CPU: 0 PID: 434 Comm: kworker/0:2 Not tainted 4.19.23-00084-g454a789-dirty #123 Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) Workqueue: usb_hub_wq hub_event [<8011237c>] (unwind_backtrace) from [<8010d74c>] (show_stack+0x10/0x14) [<8010d74c>] (show_stack) from [<809c4324>] (dump_stack+0xa8/0xd4) [<809c4324>] (dump_stack) from [<8014195c>] (process_one_work+0x710/0x808) [<8014195c>] (process_one_work) from [<80141a80>] (worker_thread+0x2c/0x564) [<80141a80>] (worker_thread) from [<80147bcc>] (kthread+0x13c/0x16c) [<80147bcc>] (kthread) from [<801010b4>] (ret_from_fork+0x14/0x20) Exception stack(0xed1d9fb0 to 0xed1d9ff8) 9fa0: 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000
====================================================== WARNING: possible circular locking dependency detected 4.19.23-00084-g454a789-dirty #123 Not tainted ------------------------------------------------------ kworker/0:2/434 is trying to acquire lock: e29cf799 ((wq_completion)"events"){+.+.}, at: process_one_work+0x174/0x808
but task is already holding lock: 18d5dcdf (&devinfo->dev_init_lock){+.+.}, at: brcmf_usb_probe+0x78/0x550 [brcmfmac]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&devinfo->dev_init_lock){+.+.}: mutex_lock_nested+0x1c/0x24 brcmf_usb_probe+0x78/0x550 [brcmfmac] usb_probe_interface+0xc0/0x1bc really_probe+0x228/0x2c0 __driver_attach+0xe4/0xe8 bus_for_each_dev+0x68/0xb4 bus_add_driver+0x19c/0x214 driver_register+0x78/0x110 usb_register_driver+0x84/0x148 process_one_work+0x228/0x808 worker_thread+0x2c/0x564 kthread+0x13c/0x16c ret_from_fork+0x14/0x20 (null)
-> #1 (brcmf_driver_work){+.+.}: worker_thread+0x2c/0x564 kthread+0x13c/0x16c ret_from_fork+0x14/0x20 (null)
-> #0 ((wq_completion)"events"){+.+.}: process_one_work+0x1b8/0x808 worker_thread+0x2c/0x564 kthread+0x13c/0x16c ret_from_fork+0x14/0x20 (null)
other info that might help us debug this:
Chain exists of: (wq_completion)"events" --> brcmf_driver_work --> &devinfo->dev_init_lock
Possible unsafe locking scenario:
CPU0 CPU1 ---- ---- lock(&devinfo->dev_init_lock); lock(brcmf_driver_work); lock(&devinfo->dev_init_lock); lock((wq_completion)"events");
*** DEADLOCK ***
1 lock held by kworker/0:2/434: #0: 18d5dcdf (&devinfo->dev_init_lock){+.+.}, at: brcmf_usb_probe+0x78/0x550 [brcmfmac]
stack backtrace: CPU: 0 PID: 434 Comm: kworker/0:2 Not tainted 4.19.23-00084-g454a789-dirty #123 Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) Workqueue: events request_firmware_work_func [<8011237c>] (unwind_backtrace) from [<8010d74c>] (show_stack+0x10/0x14) [<8010d74c>] (show_stack) from [<809c4324>] (dump_stack+0xa8/0xd4) [<809c4324>] (dump_stack) from [<80172838>] (print_circular_bug+0x210/0x330) [<80172838>] (print_circular_bug) from [<80175940>] (__lock_acquire+0x160c/0x1a30) [<80175940>] (__lock_acquire) from [<8017671c>] (lock_acquire+0xe0/0x268) [<8017671c>] (lock_acquire) from [<80141404>] (process_one_work+0x1b8/0x808) [<80141404>] (process_one_work) from [<80141a80>] (worker_thread+0x2c/0x564) [<80141a80>] (worker_thread) from [<80147bcc>] (kthread+0x13c/0x16c) [<80147bcc>] (kthread) from [<801010b4>] (ret_from_fork+0x14/0x20) Exception stack(0xed1d9fb0 to 0xed1d9ff8) 9fa0: 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000
Signed-off-by: Piotr Figiel p.figiel@camlintechnologies.com Signed-off-by: Kalle Valo kvalo@codeaurora.org Signed-off-by: Sasha Levin sashal@kernel.org --- .../wireless/broadcom/brcm80211/brcmfmac/usb.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-)
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c index e9cbfd077710a..a513990cd1d6a 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c @@ -160,7 +160,7 @@ struct brcmf_usbdev_info {
struct usb_device *usbdev; struct device *dev; - struct mutex dev_init_lock; + struct completion dev_init_done;
int ctl_in_pipe, ctl_out_pipe; struct urb *ctl_urb; /* URB for control endpoint */ @@ -1193,11 +1193,11 @@ static void brcmf_usb_probe_phase2(struct device *dev, int ret, if (ret) goto error;
- mutex_unlock(&devinfo->dev_init_lock); + complete(&devinfo->dev_init_done); return; error: brcmf_dbg(TRACE, "failed: dev=%s, err=%d\n", dev_name(dev), ret); - mutex_unlock(&devinfo->dev_init_lock); + complete(&devinfo->dev_init_done); device_release_driver(dev); }
@@ -1265,7 +1265,7 @@ static int brcmf_usb_probe_cb(struct brcmf_usbdev_info *devinfo) if (ret) goto fail; /* we are done */ - mutex_unlock(&devinfo->dev_init_lock); + complete(&devinfo->dev_init_done); return 0; } bus->chip = bus_pub->devid; @@ -1325,11 +1325,10 @@ brcmf_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
devinfo->usbdev = usb; devinfo->dev = &usb->dev; - /* Take an init lock, to protect for disconnect while still loading. + /* Init completion, to protect for disconnect while still loading. * Necessary because of the asynchronous firmware load construction */ - mutex_init(&devinfo->dev_init_lock); - mutex_lock(&devinfo->dev_init_lock); + init_completion(&devinfo->dev_init_done);
usb_set_intfdata(intf, devinfo);
@@ -1407,7 +1406,7 @@ brcmf_usb_probe(struct usb_interface *intf, const struct usb_device_id *id) return 0;
fail: - mutex_unlock(&devinfo->dev_init_lock); + complete(&devinfo->dev_init_done); kfree(devinfo); usb_set_intfdata(intf, NULL); return ret; @@ -1422,7 +1421,7 @@ brcmf_usb_disconnect(struct usb_interface *intf) devinfo = (struct brcmf_usbdev_info *)usb_get_intfdata(intf);
if (devinfo) { - mutex_lock(&devinfo->dev_init_lock); + wait_for_completion(&devinfo->dev_init_done); /* Make sure that devinfo still exists. Firmware probe routines * may have released the device and cleared the intfdata. */