From a8433138c41b421900a5a4bb4caa5c589cea3878 Mon Sep 17 00:00:00 2001 From: Tonghao Zhang Date: Mon, 24 Sep 2018 07:00:41 -0700 Subject: [PATCH] PCI/MSI: Warn and return error if driver enables MSI/MSI-X twice [ Upstream commit 4c1ef72e9b71a19fb405ebfcd37c0a5e16fa44ca ] It is a serious driver defect to enable MSI or MSI-X more than once. Doing so may panic the kernel as in the stack trace below: Call Trace: sysfs_add_one+0xa5/0xd0 create_dir+0x7c/0xe0 sysfs_create_subdir+0x1c/0x20 internal_create_group+0x6d/0x290 sysfs_create_groups+0x4a/0xa0 populate_msi_sysfs+0x1cd/0x210 pci_enable_msix+0x31c/0x3e0 igbuio_pci_open+0x72/0x300 [igb_uio] uio_open+0xcc/0x120 [uio] chrdev_open+0xa1/0x1e0 [...] do_sys_open+0xf3/0x1f0 SyS_open+0x1e/0x20 system_call_fastpath+0x16/0x1b ---[ end trace 11042e2848880209 ]--- Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffffa056b4fa We want to keep the WARN_ON() and stack trace so the driver can be fixed, but we can avoid the kernel panic by returning an error. We may still get warnings like this: Call Trace: pci_enable_msix+0x3c9/0x3e0 igbuio_pci_open+0x72/0x300 [igb_uio] uio_open+0xcc/0x120 [uio] chrdev_open+0xa1/0x1e0 [...] do_sys_open+0xf3/0x1f0 SyS_open+0x1e/0x20 system_call_fastpath+0x16/0x1b ------------[ cut here ]------------ WARNING: at fs/sysfs/dir.c:526 sysfs_add_one+0xa5/0xd0() sysfs: cannot create duplicate filename '/devices/pci0000:00/0000:00:03.0/0000:01:00.1/msi_irqs' Signed-off-by: Tonghao Zhang [bhelgaas: changelog, fix patch whitespace, remove !!] Signed-off-by: Bjorn Helgaas Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/pci/msi.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index 0e9a9db..37f393f 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -981,7 +981,6 @@ static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries, } } } - WARN_ON(!!dev->msix_enabled); /* Check whether driver already requested for MSI irq */ if (dev->msi_enabled) { @@ -1068,8 +1067,6 @@ static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec, if (!pci_msi_supported(dev, minvec)) return -EINVAL; - WARN_ON(!!dev->msi_enabled); - /* Check whether driver already requested MSI-X irqs */ if (dev->msix_enabled) { dev_info(&dev->dev, @@ -1080,6 +1077,9 @@ static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec, if (maxvec < minvec) return -ERANGE; + if (WARN_ON_ONCE(dev->msi_enabled)) + return -EINVAL; + nvec = pci_msi_vec_count(dev); if (nvec < 0) return nvec; @@ -1138,6 +1138,9 @@ static int __pci_enable_msix_range(struct pci_dev *dev, if (maxvec < minvec) return -ERANGE; + if (WARN_ON_ONCE(dev->msix_enabled)) + return -EINVAL; + for (;;) { if (affinity) { nvec = irq_calc_affinity_vectors(dev->irq_affinity, -- 2.7.4