The quilt patch titled Subject: kexec: prevent redundant IRQ masking by checking state before shutdown has been removed from the -mm tree. Its filename was kexec-prevent-redundant-irq-masking-by-checking-state-before-shutdown.patch This patch was dropped because it is obsolete ------------------------------------------------------ From: Eliav Farber <farbere@xxxxxxxxxx> Subject: kexec: prevent redundant IRQ masking by checking state before shutdown Date: Wed, 4 Dec 2024 14:20:03 +0000 During machine kexec, the function machine_kexec_mask_interrupts() is responsible for disabling or masking all interrupts. While the irq_disable hook ensures that an already-disabled IRQ is not disabled again, the current implementation unconditionally invokes the irq_mask() function for every interrupt descriptor, even when the interrupt is already masked. A specific issue was observed in the crash kernel flow after unbinding a device (prior to kexec) that used a GPIO as an IRQ source. The warning was triggered by the gpiochip_disable_irq() function, which attempted to clear the FLAG_IRQ_IS_ENABLED flag when FLAG_USED_AS_IRQ was not set: ``` void gpiochip_disable_irq(struct gpio_chip *gc, unsigned int offset) { struct gpio_desc *desc = gpiochip_get_desc(gc, offset); if (!IS_ERR(desc) && !WARN_ON(!test_bit(FLAG_USED_AS_IRQ, &desc->flags))) clear_bit(FLAG_IRQ_IS_ENABLED, &desc->flags); } ``` This issue surfaced after commit a8173820f441 ("gpio: gpiolib: Allow GPIO IRQs to lazy disable") introduced lazy disablement for GPIO IRQs. It replaced disable/enable hooks with mask/unmask hooks. Unlike the disable hook, the mask hook doesn't handle already-masked IRQs. When a GPIO-IRQ driver is unbound, the IRQ is released, triggering __irq_disable() and irq_state_set_masked(). A subsequent call to machine_kexec_mask_interrupts() re-invokes chip->irq_mask(). This results in a call chain, including gpiochip_irq_mask() and gpiochip_disable_irq(). Since FLAG_USED_AS_IRQ was cleared earlier, a warning occurs. Replace calls to irq_mask() and irq_disable() hooks with a simplified call to irq_shutdown(), and check if the interrupt is started (irqd_is_started) before calling the shutdown. Link: https://lkml.kernel.org/r/20241204142003.32859-3-farbere@xxxxxxxxxx Signed-off-by: Eliav Farber <farbere@xxxxxxxxxx> Cc: Aditya Gupta <adityag@xxxxxxxxxxxxx> Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx> Cc: Baoquan He <bhe@xxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx> Cc: Hari Bathini <hbathini@xxxxxxxxxxxxx> Cc: Jonathan Chocron <jonnyc@xxxxxxxxxx> Cc: Madhavan Srinivasan <maddy@xxxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Naveen N Rao <naveen@xxxxxxxxxx> Cc: Nicholas Piggin <npiggin@xxxxxxxxx> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx> Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxx> Cc: Ryo Takakura <takakura@xxxxxxxxxxxxx> Cc: Song Shuai <songshuaishuai@xxxxxxxxxxx> Cc: Sourabh Jain <sourabhjain@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/irq/kexec.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) --- a/kernel/irq/kexec.c~kexec-prevent-redundant-irq-masking-by-checking-state-before-shutdown +++ a/kernel/irq/kexec.c @@ -17,7 +17,7 @@ void machine_kexec_mask_interrupts(void) int check_eoi = 1; chip = irq_desc_get_chip(desc); - if (!chip) + if (!chip || !irqd_is_started(&desc->irq_data)) continue; if (IS_ENABLED(CONFIG_GENERIC_IRQ_KEXEC_CLEAR_VM_FORWARD)) { @@ -31,10 +31,6 @@ void machine_kexec_mask_interrupts(void) if (check_eoi && chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data)) chip->irq_eoi(&desc->irq_data); - if (chip->irq_mask) - chip->irq_mask(&desc->irq_data); - - if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data)) - chip->irq_disable(&desc->irq_data); + irq_shutdown(desc); } } _ Patches currently in -mm which might be from farbere@xxxxxxxxxx are