From 6ca595a70bc46e1a0eea3ee0681360f41555bfd9 Mon Sep 17 00:00:00 2001 From: Hoan Tran Date: Mon, 14 Nov 2016 11:19:02 -0800 Subject: [PATCH] mailbox: PCC: Fix lockdep warning when request PCC channel This patch fixes the lockdep warning below DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)) ------------[ cut here ]------------ WARNING: CPU: 1 PID: 1 at linux-next/kernel/locking/lockdep.c:2876 lockdep_trace_alloc+0xe0/0xf0 Modules linked in: CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.8.0-11756-g86c5152 #46 ... Call trace: Exception stack(0xffff8007da837890 to 0xffff8007da8379c0) 7880: ffff8007da834000 0001000000000000 78a0: ffff8007da837a70 ffff0000081111a0 00000000600000c5 000000000000003d 78c0: 9374bc6a7f3c7832 0000000000381878 ffff000009db7ab8 000000000000002f 78e0: ffff00000811aabc ffff000008be2548 ffff8007da837990 ffff00000811adf8 7900: ffff8007da834000 00000000024080c0 00000000000000c0 ffff000009021000 7920: 0000000000000000 0000000000000000 ffff000008c8f7c8 ffff8007da579810 7940: 000000000000002f ffff8007da858000 0000000000000000 0000000000000001 7960: 0000000000000001 0000000000000000 ffff00000811a468 0000000000000002 7980: 656c62617369645f 0000000000038187 00000000000000ee ffff8007da837850 79a0: ffff000009db50c0 ffff000009db569d 0000000000000006 ffff000089db568f [] lockdep_trace_alloc+0xe0/0xf0 [] __kmalloc_track_caller+0x50/0x250 [] devres_alloc_node+0x28/0x60 [] devm_request_threaded_irq+0x50/0xe0 [] pcc_mbox_request_channel+0x110/0x170 [] acpi_cppc_processor_probe+0x264/0x414 [] __acpi_processor_start+0x28/0xa0 [] acpi_processor_start+0x44/0x54 [] driver_probe_device+0x1fc/0x2b0 [] __driver_attach+0xb4/0xc0 [] bus_for_each_dev+0x5c/0xa0 [] driver_attach+0x20/0x30 [] bus_add_driver+0x110/0x230 [] driver_register+0x60/0x100 [] acpi_processor_driver_init+0x2c/0xb0 [] do_one_initcall+0x38/0x130 [] kernel_init_freeable+0x210/0x2b4 [] kernel_init+0x10/0x110 [] ret_from_fork+0x10/0x50 It's because the spinlock inside pcc_mbox_request_channel() is kept too long. This patch releases spinlock before request_irq() and free_irq() to fix this issue as spinlock is only needed to protect the channel data. Signed-off-by: Hoan Tran Reviewed-by: Prashanth Prakash Signed-off-by: Rafael J. Wysocki --- drivers/mailbox/pcc.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c index 08c87fadca8c..1f32688c312d 100644 --- a/drivers/mailbox/pcc.c +++ b/drivers/mailbox/pcc.c @@ -65,6 +65,7 @@ #include #include #include +#include #include "mailbox.h" @@ -267,6 +268,8 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl, if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone) chan->txdone_method |= TXDONE_BY_ACK; + spin_unlock_irqrestore(&chan->lock, flags); + if (pcc_doorbell_irq[subspace_id] > 0) { int rc; @@ -275,12 +278,11 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl, if (unlikely(rc)) { dev_err(dev, "failed to register PCC interrupt %d\n", pcc_doorbell_irq[subspace_id]); + pcc_mbox_free_channel(chan); chan = ERR_PTR(rc); } } - spin_unlock_irqrestore(&chan->lock, flags); - return chan; } EXPORT_SYMBOL_GPL(pcc_mbox_request_channel); @@ -304,20 +306,19 @@ void pcc_mbox_free_channel(struct mbox_chan *chan) return; } + if (pcc_doorbell_irq[id] > 0) + devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan); + spin_lock_irqsave(&chan->lock, flags); chan->cl = NULL; chan->active_req = NULL; if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK)) chan->txdone_method = TXDONE_BY_POLL; - if (pcc_doorbell_irq[id] > 0) - devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan); - spin_unlock_irqrestore(&chan->lock, flags); } EXPORT_SYMBOL_GPL(pcc_mbox_free_channel); - /** * pcc_send_data - Called from Mailbox Controller code. Used * here only to ring the channel doorbell. The PCC client -- 2.20.1