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Mon, 11 Oct 2021 01:52:13 -0700 (PDT) MIME-Version: 1.0 References: <20211011084049.53643-1-wanghai38@huawei.com> In-Reply-To: <20211011084049.53643-1-wanghai38@huawei.com> From: Barry Song <21cnbao@gmail.com> Date: Mon, 11 Oct 2021 21:52:02 +1300 Message-ID: Subject: Re: [PATCH] PCI/MSI: fix page fault when msi_populate_sysfs() failed To: Wang Hai Cc: Bjorn Helgaas , Marc Zyngier , Thomas Gleixner , Barry Song , Greg Kroah-Hartman , linux-pci@vger.kernel.org, LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 11, 2021 at 9:24 PM Wang Hai 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 > Signed-off-by: Wang Hai Acked-by: Barry Song > --- > 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