Date:   Wed, 11 Aug 2021 13:52:02 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Valentin Schneider <valentin.schneider@....com>,
        Serge Semin <fancer.lancer@...il.com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-rt-users@...r.kernel.org, Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Marc Zyngier <maz@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Mel Gorman <mgorman@...hsingularity.net>
Subject: Re: [SPLAT 3/3] gpio: dwapb: Sleeping spinlocks down IRQ mapping

+Cc: Serge, maintainer of the driver

On Tue, Aug 10, 2021 at 7:34 PM Valentin Schneider
<valentin.schneider@....com> wrote:
>
> [   11.549741] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:35
> [   11.549745] in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 553, name: systemd-udevd
> [   11.549747] 4 locks held by systemd-udevd/553:
> [   11.549749] #0: ffff00080338b168 (&dev->mutex){....}-{0:0}, at: __device_driver_lock (drivers/base/dd.c:1029)
> [   11.549760] #1: ffff800011df0780 (irq_domain_mutex){+.+.}-{3:3}, at: irq_domain_associate (kernel/irq/irqdomain.c:576)
> [   11.549769] #2: ffff0008112a6900 (lock_class){....}-{2:2}, at: __irq_get_desc_lock (kernel/irq/irqdesc.c:857)
> [   11.549775] #3: ffff0008112a59c8 (&gc->bgpio_lock){+.+.}-{0:0}, at: dwapb_irq_ack (drivers/gpio/gpio-dwapb.c:151 drivers/gpio/gpio-dwapb.c:233) gpio_dwapb
> [   11.549783] irq event stamp: 157476
> [   11.549785] hardirqs last enabled at (157475): _raw_spin_unlock_irqrestore (./include/linux/spinlock_api_smp.h:160 kernel/locking/spinlock.c:194)
> [   11.549790] hardirqs last disabled at (157476): _raw_spin_lock_irqsave (./include/linux/spinlock_api_smp.h:108 kernel/locking/spinlock.c:162)
> [   11.549793] softirqs last enabled at (0): copy_process (./include/linux/lockdep.h:195 ./include/linux/lockdep.h:202 ./include/linux/lockdep.h:208 ./include/linux/seqlock.h:78 kernel/fork.c:2084)
> [   11.549797] softirqs last disabled at (0): 0x0
> [   11.549801] Preemption disabled at:
> [   11.549802] __irq_get_desc_lock (kernel/irq/irqdesc.c:857)
> [   11.549806] CPU: 22 PID: 553 Comm: systemd-udevd Tainted: G        W         5.14.0-rc4-rt6-torture+ #56
> [   11.549808] Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 1.0 06/28/2019
> [   11.549810] Call trace:
> [   11.549811] dump_backtrace (arch/arm64/kernel/stacktrace.c:151)
> [   11.549814] show_stack (arch/arm64/kernel/stacktrace.c:217)
> [   11.549815] dump_stack_lvl (lib/dump_stack.c:106)
> [   11.549819] dump_stack (lib/dump_stack.c:113)
> [   11.549821] ___might_sleep (kernel/sched/core.c:9306)
> [   11.549824] rt_spin_lock (kernel/locking/rtmutex.c:1641 (discriminator 4) kernel/locking/spinlock_rt.c:30 (discriminator 4) kernel/locking/spinlock_rt.c:36 (discriminator 4) kernel/locking/spinlock_rt.c:44 (discriminator 4))
> [   11.549827] dwapb_irq_ack (drivers/gpio/gpio-dwapb.c:151 drivers/gpio/gpio-dwapb.c:233) gpio_dwapb
> [   11.549831] __irq_do_set_handler (kernel/irq/chip.c:414 kernel/irq/chip.c:406 kernel/irq/chip.c:1009)
> [   11.549833] __irq_set_handler (kernel/irq/internals.h:178 kernel/irq/chip.c:1053)
> [   11.549836] irq_set_chip_and_handler_name (kernel/irq/chip.c:1080)
> [   11.549838] gpiochip_irq_map (drivers/gpio/gpiolib.c:1262)
> [   11.549842] irq_domain_associate (kernel/irq/irqdomain.c:579)
> [   11.549845] irq_create_mapping_affinity (kernel/irq/irqdomain.c:716)
> [   11.549848] gpiochip_to_irq (drivers/gpio/gpiolib.c:1365)
> [   11.549851] gpiod_to_irq (drivers/gpio/gpiolib.c:3082)
> [   11.549853] acpi_gpiochip_alloc_event (drivers/gpio/gpiolib-acpi.c:422)
> [   11.549856] acpi_walk_resource_buffer (drivers/acpi/acpica/rsxface.c:548)
> [   11.549859] acpi_walk_resources (drivers/acpi/acpica/rsxface.c:623 drivers/acpi/acpica/rsxface.c:594)
> [   11.549862] acpi_gpiochip_request_interrupts (drivers/gpio/gpiolib-acpi.c:505)
> [   11.549864] gpiochip_add_data_with_key (drivers/gpio/gpiolib.c:748)
> [   11.549867] devm_gpiochip_add_data_with_key (drivers/gpio/gpiolib-devres.c:510)
> [   11.549869] dwapb_gpio_probe (drivers/gpio/gpio-dwapb.c:517 drivers/gpio/gpio-dwapb.c:712) gpio_dwapb
> [   11.549873] platform_probe (drivers/base/platform.c:1428)
> [   11.549876] really_probe (drivers/base/dd.c:517 drivers/base/dd.c:595 drivers/base/dd.c:541)
> [   11.549877] __driver_probe_device (drivers/base/dd.c:747)
> [   11.549879] driver_probe_device (drivers/base/dd.c:777)
> [   11.549881] __driver_attach (drivers/base/dd.c:1137)
> [   11.549883] bus_for_each_dev (drivers/base/bus.c:301)
> [   11.549885] driver_attach (drivers/base/dd.c:1154)
> [   11.549887] bus_add_driver (drivers/base/bus.c:619)
> [   11.549888] driver_register (drivers/base/driver.c:171)
> [   11.549890] __platform_driver_register (drivers/base/platform.c:875)
> [   11.549893] dwapb_gpio_driver_init (drivers/gpio/gpio-dwapb.c:343) gpio_dwapb
> [   11.549897] do_one_initcall (init/main.c:1282)
> [   11.549900] do_init_module (kernel/module.c:3690)
> [   11.549904] load_module (kernel/module.c:4091)
> [   11.549906] __do_sys_finit_module (kernel/module.c:4182)
> [   11.549909] __arm64_sys_finit_module (kernel/module.c:4159)
> [   11.549911] invoke_syscall (./arch/arm64/include/asm/current.h:19 ./arch/arm64/include/asm/compat.h:183 arch/arm64/kernel/syscall.c:57)
> [   11.549914] el0_svc_common (./arch/arm64/include/asm/daifflags.h:28 arch/arm64/kernel/syscall.c:153)
> [   11.549917] do_el0_svc (arch/arm64/kernel/syscall.c:185)
> [   11.549919] el0_svc (arch/arm64/kernel/entry-common.c:512)
> [   11.549922] el0t_64_sync_handler (arch/arm64/kernel/entry-common.c:528)
> [   11.549924] el0t_64_sync (arch/arm64/kernel/entry.S:574)

As Thomas said already the usual fix for GPIO drivers is to switch to
the raw version of spin locks. See other drivers for the example of
such conversion (yet, the IRQ handler cases might be needing the
additional care).

-- 
With Best Regards,
Andy Shevchenko

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