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 --- 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 496ed9130600..536e9a5cd2b1 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -958,7 +958,6 @@ 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) { @@ -1028,8 +1027,6 @@ 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, @@ -1040,6 +1037,9 @@ 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; @@ -1088,6 +1088,9 @@ 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 (affd) { nvec = irq_calc_affinity_vectors(minvec, nvec, affd);