From 68ea85df15d111d82fc474cbe104174791169355 Mon Sep 17 00:00:00 2001 From: Himanshu Madhani Date: Tue, 8 Jul 2025 22:25:30 +0000 Subject: [PATCH 1/2] PCI/MSI: Prevent recursive locking in pci_msix_write_tph_tag() pci_msix_write_tph_tag() takes the per device MSI descriptor mutex and then invokes msi_domain_get_virq(), which takes the same mutex again. That obviously results in a system hang which is exposed by a softlockup or lockdep warning. Move the lock guard after the invocation of msi_domain_get_virq() to fix this. [ tglx: Massage changelog by adding a proper explanation and removing the not really useful stacktrace ] Fixes: d5124a9957b2 ("PCI/MSI: Provide a sane mechanism for TPH") Reported-by: Jorge Lopez Suggested-by: Thomas Gleixner Signed-off-by: Himanshu Madhani Signed-off-by: Thomas Gleixner Tested-by: Jorge Lopez Link: https://lore.kernel.org/all/20250708222530.1041477-1-himanshu.madhani@oracle.com --- drivers/pci/msi/msi.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c index 6ede55a7c5e6..d686488f4111 100644 --- a/drivers/pci/msi/msi.c +++ b/drivers/pci/msi/msi.c @@ -934,10 +934,12 @@ int pci_msix_write_tph_tag(struct pci_dev *pdev, unsigned int index, u16 tag) if (!pdev->msix_enabled) return -ENXIO; - guard(msi_descs_lock)(&pdev->dev); virq = msi_get_virq(&pdev->dev, index); if (!virq) return -ENXIO; + + guard(msi_descs_lock)(&pdev->dev); + /* * This is a horrible hack, but short of implementing a PCI * specific interrupt chip callback and a huge pile of From a8b289f0f2dcbadd8c207ad8f33cf7ba2b4eb088 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 10 Jul 2025 10:00:12 +0200 Subject: [PATCH 2/2] irqchip/irq-msi-lib: Fix build with PCI disabled The armada-370-xp irqchip fails in some randconfig builds because of a missing declaration: In file included from drivers/irqchip/irq-armada-370-xp.c:23: include/linux/irqchip/irq-msi-lib.h:25:39: error: 'struct msi_domain_info' declared inside parameter list will not be visible outside of this definition or declaration [-Werror] Add a forward declaration for the msi_domain_info structure. [ tglx: Fixed up the subsystem prefix. Is it really that hard to get right? ] Fixes: e51b27438a10 ("irqchip: Make irq-msi-lib.h globally available") Signed-off-by: Arnd Bergmann Signed-off-by: Thomas Gleixner Acked-by: Marc Zyngier Link: https://lore.kernel.org/all/20250710080021.2303640-1-arnd@kernel.org --- include/linux/irqchip/irq-msi-lib.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/linux/irqchip/irq-msi-lib.h b/include/linux/irqchip/irq-msi-lib.h index dd8d1d138544..224ac28e88d7 100644 --- a/include/linux/irqchip/irq-msi-lib.h +++ b/include/linux/irqchip/irq-msi-lib.h @@ -17,6 +17,7 @@ #define MATCH_PLATFORM_MSI BIT(DOMAIN_BUS_PLATFORM_MSI) +struct msi_domain_info; int msi_lib_irq_domain_select(struct irq_domain *d, struct irq_fwspec *fwspec, enum irq_domain_bus_token bus_token);