[LG Optimus 4X HD] arararagi:
I've approximately figured out that it's a synchronisation race condition in the kernel.

That means it's not related to airplane mode or data on/off or WiFi on/off.

<6>[13:06:08 13:38:48.346] ARARARAGI Release baseband_xmm_power wakelock line 500
<4>[13:06:08 13:38:48.346] [<c001503c>] (unwind_backtrace+0x0/0xec) from [<c07107c4>] (dump_stack+0x20/0x24)
<4>[13:06:08 13:38:48.346] [<c07107c4>] (dump_stack+0x20/0x24) from [<c004efe0>] (baseband_xmm_set_power_status+0x15c/0x2cc)
<4>[13:06:08 13:38:48.346] [<c004efe0>] (baseband_xmm_set_power_status+0x15c/0x2cc) from [<c0050bf0>] (x3_usb_hsic_postsuspend+0x1c/0x24)
<4>[13:06:08 13:38:48.346] [<c0050bf0>] (x3_usb_hsic_postsuspend+0x1c/0x24) from [<c0033790>] (tegra_usb_phy_post_suspend+0x60/0x68)
<4>[13:06:08 13:38:48.346] [<c0033790>] (tegra_usb_phy_post_suspend+0x60/0x68) from [<c03eb00c>] (tegra_ehci_hub_control+0x240/0x2b4)
<4>[13:06:08 13:38:48.346] [<c03eb00c>] (tegra_ehci_hub_control+0x240/0x2b4) from [<c03d9b50>] (usb_hcd_submit_urb+0x44c/0x630)
<4>[13:06:08 13:38:48.346] [<c03d9b50>] (usb_hcd_submit_urb+0x44c/0x630) from [<c03da92c>] (usb_submit_urb+0x28c/0x2b0)
<4>[13:06:08 13:38:48.346] [<c03da92c>] (usb_submit_urb+0x28c/0x2b0) from [<c03db9e4>] (usb_start_wait_urb+0x50/0xbc)
<4>[13:06:08 13:38:48.346] [<c03db9e4>] (usb_start_wait_urb+0x50/0xbc) from [<c03dbc4c>] (usb_control_msg+0xd0/0xf4)
<4>[13:06:08 13:38:48.346] [<c03dbc4c>] (usb_control_msg+0xd0/0xf4) from [<c03d36a8>] (set_port_feature+0x54/0x5c)
<4>[13:06:08 13:38:48.346] [<c03d36a8>] (set_port_feature+0x54/0x5c) from [<c03d6660>] (usb_port_suspend+0xa4/0x12c)
<4>[13:06:08 13:38:48.346] [<c03d6660>] (usb_port_suspend+0xa4/0x12c) from [<c03e4d60>] (generic_suspend+0x38/0x44)
<4>[13:06:08 13:38:48.346] [<c03e4d60>] (generic_suspend+0x38/0x44) from [<c03ddf6c>] (usb_suspend_both+0x134/0x1c8)
<4>[13:06:08 13:38:48.346] [<c03ddf6c>] (usb_suspend_both+0x134/0x1c8) from [<c03dea88>] (usb_runtime_suspend+0x38/0x64)
<4>[13:06:08 13:38:48.346] [<c03dea88>] (usb_runtime_suspend+0x38/0x64) from [<c033ad60>] (rpm_callback+0x5c/0x7c)
<6>[13:06:08 13:38:48.346] ARARARAGI Already held baseband_xmm_power wakelock line 754
<4>[13:06:08 13:38:48.356] [<c001503c>] (unwind_backtrace+0x0/0xec) from [<c07107c4>] (dump_stack+0x20/0x24)
<4>[13:06:08 13:38:48.356] [<c07107c4>] (dump_stack+0x20/0x24) from [<c004e750>] (baseband_xmm_power_L2_resume+0x60/0x118)
<4>[13:06:08 13:38:48.356] [<c004e750>] (baseband_xmm_power_L2_resume+0x60/0x118) from [<c004f11c>] (baseband_xmm_set_power_status+0x298/0x2cc)
<4>[13:06:08 13:38:48.356] [<c004f11c>] (baseband_xmm_set_power_status+0x298/0x2cc) from [<c004f244>] (baseband_xmm_power_ipc_ap_wake_irq+0xf4/0x1e0)
<4>[13:06:08 13:38:48.356] [<c004f244>] (baseband_xmm_power_ipc_ap_wake_irq+0xf4/0x1e0) from [<c00b084c>] (irq_thread+0xe0/0x218)
<4>[13:06:08 13:38:48.356] [<c00b084c>] (irq_thread+0xe0/0x218) from [<c0087e74>] (kthread+0xb0/0xb8)
<4>[13:06:08 13:38:48.356] [<c0087e74>] (kthread+0xb0/0xb8) from [<c000ec44>] (kernel_thread_exit+0x0/0x8)
<4>[13:06:08 13:38:48.356] [<c033ad60>] (rpm_callback+0x5c/0x7c) from [<c033b6e4>] (rpm_suspend+0x224/0x3f4)
<4>[13:06:08 13:38:48.356] [<c033b6e4>] (rpm_suspend+0x224/0x3f4) from [<c033c1d0>] (pm_runtime_work+0x8c/0xa4)
<4>[13:06:08 13:38:48.356] [<c033c1d0>] (pm_runtime_work+0x8c/0xa4) from [<c0083428>] (process_one_work+0x2f0/0x4d4)
<4>[13:06:08 13:38:48.356] [<c0083428>] (process_one_work+0x2f0/0x4d4) from [<c00838ec>] (worker_thread+0x2e0/0x43c)
<4>[13:06:08 13:38:48.356] [<c00838ec>] (worker_thread+0x2e0/0x43c) from [<c0087e74>] (kthread+0xb0/0xb8)
<4>[13:06:08 13:38:48.356] [<c0087e74>] (kthread+0xb0/0xb8) from [<c000ec44>] (kernel_thread_exit+0x0/0x8)
<6>[13:06:08 13:38:48.376] ARARARAGI Acquire baseband_xmm_power wakelock line 472
<4>[13:06:08 13:38:48.376] [<c001503c>] (unwind_backtrace+0x0/0xec) from [<c07107c4>] (dump_stack+0x20/0x24)
<4>[13:06:08 13:38:48.376] [<c07107c4>] (dump_stack+0x20/0x24) from [<c004ef30>] (baseband_xmm_set_power_status+0xac/0x2cc)
<4>[13:06:08 13:38:48.376] [<c004ef30>] (baseband_xmm_set_power_status+0xac/0x2cc) from [<c004f2e0>] (baseband_xmm_power_ipc_ap_wake_irq+0x190/0x1e0)
<4>[13:06:08 13:38:48.376] [<c004f2e0>] (baseband_xmm_power_ipc_ap_wake_irq+0x190/0x1e0) from [<c00b084c>] (irq_thread+0xe0/0x218)
<4>[13:06:08 13:38:48.376] [<c00b084c>] (irq_thread+0xe0/0x218) from [<c0087e74>] (kthread+0xb0/0xb8)
<4>[13:06:08 13:38:48.376] [<c0087e74>] (kthread+0xb0/0xb8) from [<c000ec44>] (kernel_thread_exit+0x0/0x8)
...
...
...
...
<6>[13:06:08 14:07:45.691] ARARARAGI Release baseband_xmm_power wakelock line 500
<4>[13:06:08 14:07:45.691] [<c001503c>] (unwind_backtrace+0x0/0xec) from [<c07107c4>] (dump_stack+0x20/0x24)
<4>[13:06:08 14:07:45.691] [<c07107c4>] (dump_stack+0x20/0x24) from [<c004efe0>] (baseband_xmm_set_power_status+0x15c/0x2cc)
<4>[13:06:08 14:07:45.691] [<c004efe0>] (baseband_xmm_set_power_status+0x15c/0x2cc) from [<c0050bf0>] (x3_usb_hsic_postsuspend+0x1c/0x24)
<4>[13:06:08 14:07:45.691] [<c0050bf0>] (x3_usb_hsic_postsuspend+0x1c/0x24) from [<c0033790>] (tegra_usb_phy_post_suspend+0x60/0x68)
<4>[13:06:08 14:07:45.691] [<c0033790>] (tegra_usb_phy_post_suspend+0x60/0x68) from [<c03eb00c>] (tegra_ehci_hub_control+0x240/0x2b4)
<4>[13:06:08 14:07:45.691] [<c03eb00c>] (tegra_ehci_hub_control+0x240/0x2b4) from [<c03d9b50>] (usb_hcd_submit_urb+0x44c/0x630)
<4>[13:06:08 14:07:45.691] [<c03d9b50>] (usb_hcd_submit_urb+0x44c/0x630) from [<c03da92c>] (usb_submit_urb+0x28c/0x2b0)
<4>[13:06:08 14:07:45.691] [<c03da92c>] (usb_submit_urb+0x28c/0x2b0) from [<c03db9e4>] (usb_start_wait_urb+0x50/0xbc)
<4>[13:06:08 14:07:45.691] [<c03db9e4>] (usb_start_wait_urb+0x50/0xbc) from [<c03dbc4c>] (usb_control_msg+0xd0/0xf4)
<4>[13:06:08 14:07:45.691] [<c03dbc4c>] (usb_control_msg+0xd0/0xf4) from [<c03d36a8>] (set_port_feature+0x54/0x5c)
<4>[13:06:08 14:07:45.691] [<c03d36a8>] (set_port_feature+0x54/0x5c) from [<c03d6660>] (usb_port_suspend+0xa4/0x12c)
<4>[13:06:08 14:07:45.691] [<c03d6660>] (usb_port_suspend+0xa4/0x12c) from [<c03e4d60>] (generic_suspend+0x38/0x44)
<4>[13:06:08 14:07:45.691] [<c03e4d60>] (generic_suspend+0x38/0x44) from [<c03ddf6c>] (usb_suspend_both+0x134/0x1c8)
<4>[13:06:08 14:07:45.691] [<c03ddf6c>] (usb_suspend_both+0x134/0x1c8) from [<c03dea88>] (usb_runtime_suspend+0x38/0x64)
<4>[13:06:08 14:07:45.691] [<c03dea88>] (usb_runtime_suspend+0x38/0x64) from [<c033ad60>] (rpm_callback+0x5c/0x7c)
<4>[13:06:08 14:07:45.691] [<c033ad60>] (rpm_callback+0x5c/0x7c) from [<c033b6e4>] (rpm_suspend+0x224/0x3f4)
<4>[13:06:08 14:07:45.701] [<c033b6e4>] (rpm_suspend+0x224/0x3f4) from [<c033c1d0>] (pm_runtime_work+0x8c/0xa4)
<4>[13:06:08 14:07:45.701] [<c033c1d0>] (pm_runtime_work+0x8c/0xa4) from [<c0083428>] (process_one_work+0x2f0/0x4d4)
<4>[13:06:08 14:07:45.701] [<c0083428>] (process_one_work+0x2f0/0x4d4) from [<c00838ec>] (worker_thread+0x2e0/0x43c)
<4>[13:06:08 14:07:45.701] [<c00838ec>] (worker_thread+0x2e0/0x43c) from [<c0087e74>] (kthread+0xb0/0xb8)
<4>[13:06:08 14:07:45.701] [<c0087e74>] (kthread+0xb0/0xb8) from [<c000ec44>] (kernel_thread_exit+0x0/0x8)