Re: [PATCH] spmi: pmic-arb: Set lockdep class for hierarchical irq domains

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Tue, Jan 21, 2020 at 7:37 PM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote:

> I see the following lockdep splat in the qcom pinctrl driver when
> attempting to suspend the device.
>
>  WARNING: possible recursive locking detected
>  5.4.11 #3 Tainted: G        W
>  --------------------------------------------
>  cat/3074 is trying to acquire lock:
>  ffffff81f49804c0 (&irq_desc_lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94
>
>  but task is already holding lock:
>  ffffff81f1cc10c0 (&irq_desc_lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94
>
>  other info that might help us debug this:
>   Possible unsafe locking scenario:
>
>         CPU0
>         ----
>    lock(&irq_desc_lock_class);
>    lock(&irq_desc_lock_class);
>
>   *** DEADLOCK ***
>
>   May be due to missing lock nesting notation
>
>  6 locks held by cat/3074:
>   #0: ffffff81f01d9420 (sb_writers#7){.+.+}, at: vfs_write+0xd0/0x1a4
>   #1: ffffff81bd7d2080 (&of->mutex){+.+.}, at: kernfs_fop_write+0x12c/0x1fc
>   #2: ffffff81f4c322f0 (kn->count#337){.+.+}, at: kernfs_fop_write+0x134/0x1fc
>   #3: ffffffe411a41d60 (system_transition_mutex){+.+.}, at: pm_suspend+0x108/0x348
>   #4: ffffff81f1c5e970 (&dev->mutex){....}, at: __device_suspend+0x168/0x41c
>   #5: ffffff81f1cc10c0 (&irq_desc_lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94
>
>  stack backtrace:
>  CPU: 5 PID: 3074 Comm: cat Tainted: G        W         5.4.11 #3
>  Hardware name: Google Cheza (rev3+) (DT)
>  Call trace:
>   dump_backtrace+0x0/0x174
>   show_stack+0x20/0x2c
>   dump_stack+0xc8/0x124
>   __lock_acquire+0x460/0x2388
>   lock_acquire+0x1cc/0x210
>   _raw_spin_lock_irqsave+0x64/0x80
>   __irq_get_desc_lock+0x64/0x94
>   irq_set_irq_wake+0x40/0x144
>   qpnpint_irq_set_wake+0x28/0x34
>   set_irq_wake_real+0x40/0x5c
>   irq_set_irq_wake+0x70/0x144
>   pm8941_pwrkey_suspend+0x34/0x44
>   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
>
> Set a lockdep class when we map the irq so that irq_set_wake() doesn't
> warn about a lockdep bug that doesn't exist.
>
> Fixes: 12a9eeaebba3 ("spmi: pmic-arb: convert to v2 irq interfaces to support hierarchical IRQ chips")
> Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
> Cc: Brian Masney <masneyb@xxxxxxxxxxxxx>
> Cc: Lina Iyer <ilina@xxxxxxxxxxxxxx>
> Cc: Maulik Shah <mkshah@xxxxxxxxxxxxxx>
> Cc: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>

LGTM
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>

Yours,
Linus Walleij