On Mon, Oct 11, 2021 at 9:24 PM Wang Hai <wanghai38@xxxxxxxxxx> wrote:
>
> I got a page fault report when doing fault injection test:
>
> BUG: unable to handle page fault for address: fffffffffffffff4
> ...
> RIP: 0010:sysfs_remove_groups+0x25/0x60
> ...
> Call Trace:
> msi_destroy_sysfs+0x30/0xa0
> free_msi_irqs+0x11d/0x1b0
> __pci_enable_msix_range+0x67f/0x760
> pci_alloc_irq_vectors_affinity+0xe7/0x170
> vp_find_vqs_msix+0x129/0x560
> vp_find_vqs+0x52/0x230
> vp_modern_find_vqs+0x47/0xb0
> p9_virtio_probe+0xa1/0x460 [9pnet_virtio]
> virtio_dev_probe+0x1ed/0x2e0
> really_probe+0x1c7/0x400
> __driver_probe_device+0xa4/0x120
> driver_probe_device+0x32/0xe0
> __driver_attach+0xbf/0x130
> bus_for_each_dev+0xbb/0x110
> driver_attach+0x27/0x30
> bus_add_driver+0x1d9/0x270
> driver_register+0xa9/0x180
> register_virtio_driver+0x31/0x50
> p9_virtio_init+0x3c/0x1000 [9pnet_virtio]
> do_one_initcall+0x7b/0x380
> do_init_module+0x5f/0x21e
> load_module+0x265c/0x2c60
> __do_sys_finit_module+0xb0/0xf0
> __x64_sys_finit_module+0x1a/0x20
> do_syscall_64+0x34/0xb0
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> When populating msi_irqs sysfs failed in msi_capability_init() or
> msix_capability_init(), dev->msi_irq_groups will point to ERR_PTR(...).
> This will cause a page fault when destroying the wrong
> dev->msi_irq_groups in free_msi_irqs().
>
> Fix this by setting dev->msi_irq_groups to NULL when msi_populate_sysfs()
> failed.
>
> Fixes: 2f170814bdd2 ("genirq/msi: Move MSI sysfs handling from PCI to MSI core")
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Signed-off-by: Wang Hai <wanghai38@xxxxxxxxxx>
Acked-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
> ---
> drivers/pci/msi.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index 0099a00af361..6f75db9f3be7 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -561,6 +561,7 @@ static int msi_capability_init(struct pci_dev *dev, int nvec,
> dev->msi_irq_groups = msi_populate_sysfs(&dev->dev);
> if (IS_ERR(dev->msi_irq_groups)) {
> ret = PTR_ERR(dev->msi_irq_groups);
> + dev->msi_irq_groups = NULL;
> goto err;
> }
>
> @@ -733,6 +734,7 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries,
> dev->msi_irq_groups = msi_populate_sysfs(&dev->dev);
> if (IS_ERR(dev->msi_irq_groups)) {
> ret = PTR_ERR(dev->msi_irq_groups);
> + dev->msi_irq_groups = NULL;
Can you define a temp variable and assign it to dev->msi_irq_groups if
the temp variable
is not PTR_ERR?
> goto out_free;
> }
>
> --
> 2.17.1
>
Thanks
Barry
