5.4-stable review patch. If anyone has any objections, please let me know.
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From: Andy Shevchenko andriy.shevchenko@linux.intel.com
[ Upstream commit 953e549471cabc9d4980f1da2e9fa79f4c23da06 ]
Lockdep gives a false positive splat as it can't distinguish the lock which is taken by different IRQ descriptors from different IRQ chips that are organized in a way of a hierarchy:
====================================================== WARNING: possible circular locking dependency detected 6.12.0-rc5-next-20241101-00148-g9fabf8160b53 #562 Tainted: G W ------------------------------------------------------ modprobe/141 is trying to acquire lock: ffff899446947868 (intel_soc_pmic_bxtwc:502:(&bxtwc_regmap_config)->lock){+.+.}-{4:4}, at: regmap_update_bits_base+0x33/0x90
but task is already holding lock: ffff899446947c68 (&d->lock){+.+.}-{4:4}, at: __setup_irq+0x682/0x790
which lock already depends on the new lock.
-> #3 (&d->lock){+.+.}-{4:4}: -> #2 (&desc->request_mutex){+.+.}-{4:4}: -> #1 (ipclock){+.+.}-{4:4}: -> #0 (intel_soc_pmic_bxtwc:502:(&bxtwc_regmap_config)->lock){+.+.}-{4:4}:
Chain exists of: intel_soc_pmic_bxtwc:502:(&bxtwc_regmap_config)->lock --> &desc->request_mutex --> &d->lock
Possible unsafe locking scenario:
CPU0 CPU1 ---- ---- lock(&d->lock); lock(&desc->request_mutex); lock(&d->lock); lock(intel_soc_pmic_bxtwc:502:(&bxtwc_regmap_config)->lock);
*** DEADLOCK ***
3 locks held by modprobe/141: #0: ffff8994419368f8 (&dev->mutex){....}-{4:4}, at: __driver_attach+0xf6/0x250 #1: ffff89944690b250 (&desc->request_mutex){+.+.}-{4:4}, at: __setup_irq+0x1a2/0x790 #2: ffff899446947c68 (&d->lock){+.+.}-{4:4}, at: __setup_irq+0x682/0x790
Set a lockdep class when we map the IRQ so that it doesn't warn about a lockdep bug that doesn't exist.
Fixes: 4af8be67fd99 ("regmap: Convert regmap_irq to use irq_domain") Signed-off-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Link: https://patch.msgid.link/20241101165553.4055617-1-andriy.shevchenko@linux.in... Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/base/regmap/regmap-irq.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c index 3c1e554df4eb2..54cb9a02254f9 100644 --- a/drivers/base/regmap/regmap-irq.c +++ b/drivers/base/regmap/regmap-irq.c @@ -522,12 +522,16 @@ static irqreturn_t regmap_irq_thread(int irq, void *d) return IRQ_NONE; }
+static struct lock_class_key regmap_irq_lock_class; +static struct lock_class_key regmap_irq_request_class; + static int regmap_irq_map(struct irq_domain *h, unsigned int virq, irq_hw_number_t hw) { struct regmap_irq_chip_data *data = h->host_data;
irq_set_chip_data(virq, data); + irq_set_lockdep_class(virq, ®map_irq_lock_class, ®map_irq_request_class); irq_set_chip(virq, &data->irq_chip); irq_set_nested_thread(virq, 1); irq_set_parent(virq, data->irq);