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Runyu XiaoandGreg Kroah-Hartman
4f03a15cc7
[ Upstream commit286533cb14] sch_irq_unmask() enables the GPIO IRQ and then updates the controller state through sch_irq_mask_unmask(), which takes sch->lock with spin_lock_irqsave(). The callback can be reached from irq_startup() while setting up a requested IRQ. That path is not sleepable, but on PREEMPT_RT a regular spinlock_t becomes a sleeping lock. This issue was found by our static analysis tool and then manually reviewed against the current tree. The grounded PoC kept the request_threaded_irq() -> __setup_irq() -> irq_startup() -> sch_irq_unmask() -> sch_irq_mask_unmask() carrier and used the original spin_lock_irqsave(&sch->lock) edge. Lockdep reported: BUG: sleeping function called from invalid context hardirqs last disabled at ... __setup_irq.constprop.0 ... [vuln_msv] sch_rt_spin_lock_irqsave+0x1c/0x30 [vuln_msv] sch_irq_mask_unmask.constprop.0+0x31/0x70 [vuln_msv] __setup_irq.constprop.0+0xd/0x30 [vuln_msv] Convert the SCH controller lock to raw_spinlock_t. The same lock is also used by the GPIO direction and value callbacks, but those critical sections only update MMIO-backed GPIO registers and do not contain sleepable operations. Keeping this register lock non-sleeping is therefore appropriate for the irqchip callbacks and does not change the GPIO-side locking contract. Fixes:7a81638485("gpio: sch: Add edge event support") Cc: stable@vger.kernel.org Signed-off-by: Runyu Xiao <runyu.xiao@seu.edu.cn> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com> Link: https://patch.msgid.link/20260617154035.1199948-2-runyu.xiao@seu.edu.cn Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com> [ adjusted context for 6.6's pre-MMIO `iobase` port I/O and void `sch_gpio_set()` (no set_rv `return 0;`) ] Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>