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[104.188.17.28]) by smtp.gmail.com with ESMTPSA id i2sm42307138pgi.94.2020.01.21.10.35.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Jan 2020 10:35:22 -0800 (PST) Date: Tue, 21 Jan 2020 10:35:19 -0800 From: Bjorn Andersson To: Stephen Boyd Cc: Linus Walleij , linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-gpio@vger.kernel.org, Douglas Anderson , Brian Masney , Lina Iyer , Maulik Shah Subject: Re: [PATCH] pinctrl: qcom: Don't lock around irq_set_irq_wake() Message-ID: <20200121183519.GP1511@yoga> References: <20200121180950.36959-1-swboyd@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200121180950.36959-1-swboyd@chromium.org> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Tue 21 Jan 10:09 PST 2020, Stephen Boyd wrote: > We don't need to hold the local pinctrl lock here to set irq wake on the > summary irq line. Doing so only leads to lockdep warnings instead of > protecting us from anything. Remove the locking. > > WARNING: possible circular locking dependency detected > 5.4.11 #2 Tainted: G W > ------------------------------------------------------ > cat/3083 is trying to acquire lock: > ffffff81f4fa58c0 (&irq_desc_lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94 > > but task is already holding lock: > ffffff81f4880c18 (&pctrl->lock){-.-.}, at: msm_gpio_irq_set_wake+0x48/0x7c > > which lock already depends on the new lock. > > the existing dependency chain (in reverse order) is: > > -> #1 (&pctrl->lock){-.-.}: > _raw_spin_lock_irqsave+0x64/0x80 > msm_gpio_irq_ack+0x68/0xf4 > __irq_do_set_handler+0xe0/0x180 > __irq_set_handler+0x60/0x9c > irq_domain_set_info+0x90/0xb4 > gpiochip_hierarchy_irq_domain_alloc+0x110/0x200 > __irq_domain_alloc_irqs+0x130/0x29c > irq_create_fwspec_mapping+0x1f0/0x300 > irq_create_of_mapping+0x70/0x98 > of_irq_get+0xa4/0xd4 > spi_drv_probe+0x4c/0xb0 > really_probe+0x138/0x3f0 > driver_probe_device+0x70/0x140 > __device_attach_driver+0x9c/0x110 > bus_for_each_drv+0x88/0xd0 > __device_attach+0xb0/0x160 > device_initial_probe+0x20/0x2c > bus_probe_device+0x34/0x94 > device_add+0x35c/0x3f0 > spi_add_device+0xbc/0x194 > of_register_spi_devices+0x2c8/0x408 > spi_register_controller+0x57c/0x6fc > spi_geni_probe+0x260/0x328 > platform_drv_probe+0x90/0xb0 > really_probe+0x138/0x3f0 > driver_probe_device+0x70/0x140 > device_driver_attach+0x4c/0x6c > __driver_attach+0xcc/0x154 > bus_for_each_dev+0x84/0xcc > driver_attach+0x2c/0x38 > bus_add_driver+0x108/0x1fc > driver_register+0x64/0xf8 > __platform_driver_register+0x4c/0x58 > spi_geni_driver_init+0x1c/0x24 > do_one_initcall+0x1a4/0x3e8 > do_initcall_level+0xb4/0xcc > do_basic_setup+0x30/0x48 > kernel_init_freeable+0x124/0x1a8 > kernel_init+0x14/0x100 > ret_from_fork+0x10/0x18 > > -> #0 (&irq_desc_lock_class){-.-.}: > __lock_acquire+0xeb4/0x2388 > lock_acquire+0x1cc/0x210 > _raw_spin_lock_irqsave+0x64/0x80 > __irq_get_desc_lock+0x64/0x94 > irq_set_irq_wake+0x40/0x144 > msm_gpio_irq_set_wake+0x5c/0x7c > set_irq_wake_real+0x40/0x5c > irq_set_irq_wake+0x70/0x144 > cros_ec_rtc_suspend+0x38/0x4c > platform_pm_suspend+0x34/0x60 > dpm_run_callback+0x64/0xcc > __device_suspend+0x310/0x41c > dpm_suspend+0xf8/0x298 > dpm_suspend_start+0x84/0xb4 > suspend_devices_and_enter+0xbc/0x620 > pm_suspend+0x210/0x348 > state_store+0xb0/0x108 > kobj_attr_store+0x14/0x24 > sysfs_kf_write+0x4c/0x64 > kernfs_fop_write+0x15c/0x1fc > __vfs_write+0x54/0x18c > vfs_write+0xe4/0x1a4 > ksys_write+0x7c/0xe4 > __arm64_sys_write+0x20/0x2c > el0_svc_common+0xa8/0x160 > el0_svc_handler+0x7c/0x98 > el0_svc+0x8/0xc > > other info that might help us debug this: > > Possible unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > lock(&pctrl->lock); > lock(&irq_desc_lock_class); > lock(&pctrl->lock); > lock(&irq_desc_lock_class); > > *** DEADLOCK *** > > 7 locks held by cat/3083: > #0: ffffff81f06d1420 (sb_writers#7){.+.+}, at: vfs_write+0xd0/0x1a4 > #1: ffffff81c8935680 (&of->mutex){+.+.}, at: kernfs_fop_write+0x12c/0x1fc > #2: ffffff81f4c322f0 (kn->count#337){.+.+}, at: kernfs_fop_write+0x134/0x1fc > #3: ffffffe89a641d60 (system_transition_mutex){+.+.}, at: pm_suspend+0x108/0x348 > #4: ffffff81f190e970 (&dev->mutex){....}, at: __device_suspend+0x168/0x41c > #5: ffffff81f183d8c0 (lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94 > #6: ffffff81f4880c18 (&pctrl->lock){-.-.}, at: msm_gpio_irq_set_wake+0x48/0x7c > > stack backtrace: > CPU: 4 PID: 3083 Comm: cat Tainted: G W 5.4.11 #2 > Hardware name: Google Cheza (rev3+) (DT) > Call trace: > dump_backtrace+0x0/0x174 > show_stack+0x20/0x2c > dump_stack+0xc8/0x124 > print_circular_bug+0x2ac/0x2c4 > check_noncircular+0x1a0/0x1a8 > __lock_acquire+0xeb4/0x2388 > lock_acquire+0x1cc/0x210 > _raw_spin_lock_irqsave+0x64/0x80 > __irq_get_desc_lock+0x64/0x94 > irq_set_irq_wake+0x40/0x144 > msm_gpio_irq_set_wake+0x5c/0x7c > set_irq_wake_real+0x40/0x5c > irq_set_irq_wake+0x70/0x144 > cros_ec_rtc_suspend+0x38/0x4c > platform_pm_suspend+0x34/0x60 > dpm_run_callback+0x64/0xcc > __device_suspend+0x310/0x41c > dpm_suspend+0xf8/0x298 > dpm_suspend_start+0x84/0xb4 > suspend_devices_and_enter+0xbc/0x620 > pm_suspend+0x210/0x348 > state_store+0xb0/0x108 > kobj_attr_store+0x14/0x24 > sysfs_kf_write+0x4c/0x64 > kernfs_fop_write+0x15c/0x1fc > __vfs_write+0x54/0x18c > vfs_write+0xe4/0x1a4 > ksys_write+0x7c/0xe4 > __arm64_sys_write+0x20/0x2c > el0_svc_common+0xa8/0x160 > el0_svc_handler+0x7c/0x98 > el0_svc+0x8/0xc > > Fixes: f365be092572 ("pinctrl: Add Qualcomm TLMM driver") This lock used to protect the wake_irqs bitmap, and although your change indicates that the locking was wrong before this point I think the fixes should be: Fixes: 6aced33f4974 ("pinctrl: msm: drop wake_irqs bitmap") Either way, the patch looks good. Reviewed-by: Bjorn Andersson Thanks, Bjorn > Cc: Douglas Anderson > Cc: Brian Masney > Cc: Lina Iyer > Cc: Maulik Shah > Cc: Bjorn Andersson > Signed-off-by: Stephen Boyd > --- > drivers/pinctrl/qcom/pinctrl-msm.c | 5 ----- > 1 file changed, 5 deletions(-) > > diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c > index 5d6f9f61ce02..9a8daa256a32 100644 > --- a/drivers/pinctrl/qcom/pinctrl-msm.c > +++ b/drivers/pinctrl/qcom/pinctrl-msm.c > @@ -960,7 +960,6 @@ static int msm_gpio_irq_set_wake(struct irq_data *d, unsigned int on) > { > struct gpio_chip *gc = irq_data_get_irq_chip_data(d); > struct msm_pinctrl *pctrl = gpiochip_get_data(gc); > - unsigned long flags; > > /* > * While they may not wake up when the TLMM is powered off, > @@ -971,12 +970,8 @@ static int msm_gpio_irq_set_wake(struct irq_data *d, unsigned int on) > if (d->parent_data) > irq_chip_set_wake_parent(d, on); > > - raw_spin_lock_irqsave(&pctrl->lock, flags); > - > irq_set_irq_wake(pctrl->irq, on); > > - raw_spin_unlock_irqrestore(&pctrl->lock, flags); > - > return 0; > } > > -- > Sent by a computer, using git, on the internet >