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| author | Tonghao Zhang <xiangxia.m.yue@gmail.com> | 2018-09-24 07:00:41 -0700 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2018-09-25 15:17:39 -0500 |
| commit | 4c1ef72e9b71a19fb405ebfcd37c0a5e16fa44ca (patch) | |
| tree | ba5ca29dc2d5797d8fb4d0450342c4ed7b770a8f /drivers/pci/msi.c | |
| parent | 7876320f88802b22d4e2daf7eb027dd14175a0f8 (diff) | |
| download | lwn-4c1ef72e9b71a19fb405ebfcd37c0a5e16fa44ca.tar.gz lwn-4c1ef72e9b71a19fb405ebfcd37c0a5e16fa44ca.zip | |
PCI/MSI: Warn and return error if driver enables MSI/MSI-X twice
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>
Diffstat (limited to 'drivers/pci/msi.c')
| -rw-r--r-- | drivers/pci/msi.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index f2ef896464b3..af24ed50a245 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) { pci_info(dev, "can't enable MSI (MSI-X already enabled)\n"); @@ -1039,6 +1036,9 @@ 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; @@ -1087,6 +1087,9 @@ 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); |