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authorHimanshu Madhani <himanshu.madhani@oracle.com>2025-07-08 22:25:30 +0000
committerThomas Gleixner <tglx@linutronix.de>2025-07-10 23:41:08 +0200
commit68ea85df15d111d82fc474cbe104174791169355 (patch)
tree37debc5017299a084aed7409a9e26e0cfed47476
parentd7b8f8e20813f0179d8ef519541a3527e7661d3a (diff)
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 <jorge.jo.lopez@oracle.com> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Himanshu Madhani <himanshu.madhani@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Jorge Lopez <jorge.jo.lopez@oracle.com> Link: https://lore.kernel.org/all/20250708222530.1041477-1-himanshu.madhani@oracle.com
-rw-r--r--drivers/pci/msi/msi.c4
1 files changed, 3 insertions, 1 deletions
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