Dwc lockdep fixes rpi 3.16.y #671
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Os wrapper function for spinlock init causes lockdep to show this false positive splat during boot: [ 3.789851] ============================================= [ 3.796603] [ INFO: possible recursive locking detected ] [ 3.803320] 3.16.1+ raspberrypi#5 Not tainted [ 3.808015] --------------------------------------------- [ 3.814730] khubd/18 is trying to acquire lock: [ 3.820537] (&(sl)->rlock){-.-...}, at: [<c0357168>] DWC_SPINLOCK_IRQSAVE+0xc/0x14 [ 3.830932] [ 3.830932] but task is already holding lock: [ 3.839274] (&(sl)->rlock){-.-...}, at: [<c0357168>] DWC_SPINLOCK_IRQSAVE+0xc/0x14 [ 3.849704] [ 3.849704] other info that might help us debug this: [ 3.858826] Possible unsafe locking scenario: [ 3.858826] [ 3.867334] CPU0 [ 3.871052] ---- [ 3.874721] lock(&(sl)->rlock); [ 3.879302] lock(&(sl)->rlock); [ 3.883815] [ 3.883815] *** DEADLOCK *** [ 3.883815] [ 3.892869] May be due to missing lock nesting notation [ 3.892869] [ 3.901736] 4 locks held by khubd/18: [ 3.906438] #0: (&dev->mutex){......}, at: [<c0321da8>] hub_thread+0x98/0x1000 [ 3.916026] raspberrypi#1: (&port_dev->status_lock){+.+.+.}, at: [<c032234c>] hub_thread+0x63c/0x1000 [ 3.926847] raspberrypi#2: (&bus->usb_address0_mutex){+.+.+.}, at: [<c031f164>] hub_port_init+0x5c/0xb24 [ 3.938015] raspberrypi#3: (&(sl)->rlock){-.-...}, at: [<c0357168>] DWC_SPINLOCK_IRQSAVE+0xc/0x14 [ 3.948730] [ 3.948730] stack backtrace: [ 3.955457] CPU: 0 PID: 18 Comm: khubd Not tainted 3.16.1+ raspberrypi#5 [ 3.962541] [<c00137e4>] (unwind_backtrace) from [<c0011530>] (show_stack+0x10/0x14) [ 3.972998] [<c0011530>] (show_stack) from [<c005985c>] (__lock_acquire+0x1420/0x1ae0) [ 3.983910] [<c005985c>] (__lock_acquire) from [<c005a6c8>] (lock_acquire+0x6c/0x8c) [ 3.994908] [<c005a6c8>] (lock_acquire) from [<c04a872c>] (_raw_spin_lock_irqsave+0x50/0x64) [ 4.006756] [<c04a872c>] (_raw_spin_lock_irqsave) from [<c0357168>] (DWC_SPINLOCK_IRQSAVE+0xc/0x14) [ 4.019382] [<c0357168>] (DWC_SPINLOCK_IRQSAVE) from [<c034ba9c>] (dwc_otg_hcd_select_transactions+0x20c/0x368) [ 4.033064] [<c034ba9c>] (dwc_otg_hcd_select_transactions) from [<c034c0f8>] (dwc_otg_hcd_urb_enqueue+0x158/0x1ec) [ 4.047017] [<c034c0f8>] (dwc_otg_hcd_urb_enqueue) from [<c034d8a0>] (dwc_otg_urb_enqueue+0x1a8/0x2e0) [ 4.059889] [<c034d8a0>] (dwc_otg_urb_enqueue) from [<c03258e4>] (usb_hcd_submit_urb+0xb8/0x870) [ 4.072316] [<c03258e4>] (usb_hcd_submit_urb) from [<c03276a0>] (usb_start_wait_urb+0x44/0xbc) [ 4.084786] [<c03276a0>] (usb_start_wait_urb) from [<c03277cc>] (usb_control_msg+0xb4/0xec) [ 4.097045] [<c03277cc>] (usb_control_msg) from [<c031f528>] (hub_port_init+0x420/0xb24) [ 4.109018] [<c031f528>] (hub_port_init) from [<c0322360>] (hub_thread+0x650/0x1000) [ 4.120667] [<c0322360>] (hub_thread) from [<c003ec3c>] (kthread+0xc8/0xe4) [ 4.129668] [<c003ec3c>] (kthread) from [<c000e128>] (ret_from_fork+0x14/0x2c) This is false positive because the lockdep uses the lock variable name to keep track of locks. To fix this, the spin_lock_init function can't be in a wrapper function for spinlock name to recorder correctly. I noticed similar fix was already made for mutex debugging so used similar approach and added extra macro to be used to spinlock allocation when spinlock debugging is on. Signed-off-by: Kari Suvanto <[email protected]>
Lockdep gives this splat during boot: [ 4.136748] ================================= [ 4.145487] [ INFO: inconsistent lock state ] [ 4.154157] 3.16.1+ raspberrypi#12 Not tainted [ 4.161852] --------------------------------- [ 4.170459] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. [ 4.180776] khubd/18 [HC0[0]:SC0[0]:HE1:SE1] takes: [ 4.189971] (&((spinlock_t *)hcd->lock)->rlock){?.-...}, at: [<c0351490>] dwc_otg_hcd_qh_free+0x18/0xcc [ 4.204074] {IN-HARDIRQ-W} state was registered at: [ 4.213359] [<c04a8680>] _raw_spin_lock+0x40/0x50 [ 4.222743] [<c033f010>] dwc_otg_handle_common_intr+0x44/0xd90 [ 4.233133] [<c03333c8>] dwc_otg_common_irq+0xc/0x18 [ 4.242739] [<c00634d4>] handle_irq_event_percpu+0x34/0x150 [ 4.252955] [<c006362c>] handle_irq_event+0x3c/0x5c [ 4.262395] [<c0065984>] handle_level_irq+0x8c/0x130 [ 4.271972] [<c0062e40>] generic_handle_irq+0x28/0x40 [ 4.281489] [<c000e96c>] handle_IRQ+0x30/0x84 [ 4.290442] [<c04a9698>] __irq_svc+0x38/0xd0 [ 4.299164] [<c0357194>] DWC_MODIFY_REG32+0x64/0x84 [ 4.308613] [<c0333af4>] dwc_otg_driver_probe+0x720/0x7a8 [ 4.318523] [<c02daab0>] platform_drv_probe+0x18/0x48 [ 4.328141] [<c02d926c>] really_probe+0x68/0x200 [ 4.337334] [<c02d94f8>] __driver_attach+0xa0/0xa4 [ 4.346592] [<c02d7998>] bus_for_each_dev+0x60/0x94 [ 4.355998] [<c02d8b70>] bus_add_driver+0x140/0x1ec [ 4.365262] [<c02d9b18>] driver_register+0x78/0xf8 [ 4.374561] [<c065e0f4>] dwc_otg_driver_init+0x58/0x114 [ 4.384271] [<c00086a4>] do_one_initcall+0x80/0x1cc [ 4.393661] [<c0646c94>] kernel_init_freeable+0xf0/0x1b0 [ 4.403501] [<c049d83c>] kernel_init+0x8/0xec [ 4.412308] [<c000e128>] ret_from_fork+0x14/0x2c [ 4.421444] irq event stamp: 2351 [ 4.428928] hardirqs last enabled at (2351): [<c04a89b8>] _raw_spin_unlock_irqrestore+0x7c/0x94 [ 4.442100] hardirqs last disabled at (2350): [<c04a87a0>] _raw_spin_lock_irqsave+0x1c/0x64 [ 4.454802] softirqs last enabled at (2320): [<c0023b94>] __do_softirq+0x1ac/0x26c [ 4.466739] softirqs last disabled at (2297): [<c0023f80>] irq_exit+0xac/0x100 [ 4.478260] [ 4.478260] other info that might help us debug this: [ 4.493215] Possible unsafe locking scenario: [ 4.493215] [ 4.507451] CPU0 [ 4.513932] ---- [ 4.520505] lock(&((spinlock_t *)hcd->lock)->rlock); [ 4.529767] <Interrupt> [ 4.536515] lock(&((spinlock_t *)hcd->lock)->rlock); [ 4.545951] [ 4.545951] *** DEADLOCK *** [ 4.545951] [ 4.564132] 3 locks held by khubd/18: [ 4.571884] #0: (&dev->mutex){......}, at: [<c0321da8>] hub_thread+0x98/0x1000 [ 4.583536] raspberrypi#1: (&port_dev->status_lock){+.+.+.}, at: [<c032234c>] hub_thread+0x63c/0x1000 [ 4.596241] raspberrypi#2: (&bus->usb_address0_mutex){+.+.+.}, at: [<c031f164>] hub_port_init+0x5c/0xb24 [ 4.609307] [ 4.609307] stack backtrace: [ 4.621705] CPU: 0 PID: 18 Comm: khubd Not tainted 3.16.1+ raspberrypi#12 [ 4.631643] [<c00137e4>] (unwind_backtrace) from [<c0011530>] (show_stack+0x10/0x14) [ 4.643580] [<c0011530>] (show_stack) from [<c049f650>] (print_usage_bug+0x240/0x2b0) [ 4.655608] [<c049f650>] (print_usage_bug) from [<c0057a24>] (mark_lock+0x1d0/0x67c) [ 4.667527] [<c0057a24>] (mark_lock) from [<c0058a10>] (__lock_acquire+0x5d4/0x1ae0) [ 4.679551] [<c0058a10>] (__lock_acquire) from [<c005a6c8>] (lock_acquire+0x6c/0x8c) [ 4.691610] [<c005a6c8>] (lock_acquire) from [<c04a8680>] (_raw_spin_lock+0x40/0x50) [ 4.703584] [<c04a8680>] (_raw_spin_lock) from [<c0351490>] (dwc_otg_hcd_qh_free+0x18/0xcc) [ 4.716305] [<c0351490>] (dwc_otg_hcd_qh_free) from [<c034a60c>] (dwc_otg_hcd_endpoint_disable+0x9c/0xb0) [ 4.730246] [<c034a60c>] (dwc_otg_hcd_endpoint_disable) from [<c034d650>] (endpoint_disable+0x18/0x24) [ 4.743919] [<c034d650>] (endpoint_disable) from [<c031e0d0>] (usb_ep0_reinit+0x14/0x38) [ 4.756379] [<c031e0d0>] (usb_ep0_reinit) from [<c031f3ac>] (hub_port_init+0x2a4/0xb24) [ 4.768652] [<c031f3ac>] (hub_port_init) from [<c0322360>] (hub_thread+0x650/0x1000) [ 4.780824] [<c0322360>] (hub_thread) from [<c003ec3c>] (kthread+0xc8/0xe4) [ 4.792231] [<c003ec3c>] (kthread) from [<c000e128>] (ret_from_fork+0x14/0x2c) This splat shows that the hcd spinlock is used from hard irq context and also from process context with irqs on. To fix this, use spinlock_irqsave instead of spinlock in dwc_otg_hcd_qh_free. Signed-off-by: Kari Suvanto <[email protected]>
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@P33M. Up to you. |
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@karis79 thanks for ferreting this out. |
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2 separate lockdep fixes to dwc. First one fixing false positive due to os wrapper function and second one fixing inconsistent lock state in hcd lock.