| From foo@baz Sat Nov 10 11:24:34 PST 2018 |
| From: Tonghao Zhang <xiangxia.m.yue@gmail.com> |
| Date: Mon, 24 Sep 2018 07:00:41 -0700 |
| Subject: PCI/MSI: Warn and return error if driver enables MSI/MSI-X twice |
| |
| From: Tonghao Zhang <xiangxia.m.yue@gmail.com> |
| |
| [ 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 <xiangxia.m.yue@gmail.com> |
| [bhelgaas: changelog, fix patch whitespace, remove !!] |
| Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/pci/msi.c | 9 ++++++--- |
| 1 file changed, 6 insertions(+), 3 deletions(-) |
| |
| --- a/drivers/pci/msi.c |
| +++ b/drivers/pci/msi.c |
| @@ -981,7 +981,6 @@ static int __pci_enable_msix(struct pci_ |
| } |
| } |
| } |
| - 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 |
| 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 |
| 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(struc |
| 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, |