From c2e90800aef22e7ea14ea7560ba99993f11d3616 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 12 Dec 2017 13:45:50 +0000 Subject: [PATCH] virtio_mmio: fix devm cleanup Recent rework of the virtio_mmio probe/remove paths balanced a devm_ioremap() with an iounmap() rather than its devm variant. This ends up corrupting the devm datastructures, and results in the following boot-time splat on arm64 under QEMU 2.9.0: [ 3.450397] ------------[ cut here ]------------ [ 3.453822] Trying to vfree() nonexistent vm area (00000000c05b4844) [ 3.460534] WARNING: CPU: 1 PID: 1 at mm/vmalloc.c:1525 __vunmap+0x1b8/0x220 [ 3.475898] Kernel panic - not syncing: panic_on_warn set ... [ 3.475898] [ 3.493933] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.15.0-rc3 #1 [ 3.513109] Hardware name: linux,dummy-virt (DT) [ 3.525382] Call trace: [ 3.531683] dump_backtrace+0x0/0x368 [ 3.543921] show_stack+0x20/0x30 [ 3.547767] dump_stack+0x108/0x164 [ 3.559584] panic+0x25c/0x51c [ 3.569184] __warn+0x29c/0x31c [ 3.576023] report_bug+0x1d4/0x290 [ 3.586069] bug_handler.part.2+0x40/0x100 [ 3.597820] bug_handler+0x4c/0x88 [ 3.608400] brk_handler+0x11c/0x218 [ 3.613430] do_debug_exception+0xe8/0x318 [ 3.627370] el1_dbg+0x18/0x78 [ 3.634037] __vunmap+0x1b8/0x220 [ 3.648747] vunmap+0x6c/0xc0 [ 3.653864] __iounmap+0x44/0x58 [ 3.659771] devm_ioremap_release+0x34/0x68 [ 3.672983] release_nodes+0x404/0x880 [ 3.683543] devres_release_all+0x6c/0xe8 [ 3.695692] driver_probe_device+0x250/0x828 [ 3.706187] __driver_attach+0x190/0x210 [ 3.717645] bus_for_each_dev+0x14c/0x1f0 [ 3.728633] driver_attach+0x48/0x78 [ 3.740249] bus_add_driver+0x26c/0x5b8 [ 3.752248] driver_register+0x16c/0x398 [ 3.757211] __platform_driver_register+0xd8/0x128 [ 3.770860] virtio_mmio_init+0x1c/0x24 [ 3.782671] do_one_initcall+0xe0/0x398 [ 3.791890] kernel_init_freeable+0x594/0x660 [ 3.798514] kernel_init+0x18/0x190 [ 3.810220] ret_from_fork+0x10/0x18 To fix this, we can simply rip out the explicit cleanup that the devm infrastructure will do for us when our probe function returns an error code, or when our remove function returns. We only need to ensure that we call put_device() if a call to register_virtio_device() fails in the probe path. Signed-off-by: Mark Rutland Fixes: 7eb781b1bbb7136f ("virtio_mmio: add cleanup for virtio_mmio_probe") Fixes: 25f32223bce5c580 ("virtio_mmio: add cleanup for virtio_mmio_remove") Cc: Cornelia Huck Cc: Michael S. Tsirkin Cc: weiping zhang Cc: virtualization@lists.linux-foundation.org Signed-off-by: Michael S. Tsirkin Reviewed-by: Cornelia Huck --- drivers/virtio/virtio_mmio.c | 43 ++++++++---------------------------- 1 file changed, 9 insertions(+), 34 deletions(-) diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index a9192fe4f345..c92131edfaba 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -522,10 +522,8 @@ static int virtio_mmio_probe(struct platform_device *pdev) return -EBUSY; vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL); - if (!vm_dev) { - rc = -ENOMEM; - goto free_mem; - } + if (!vm_dev) + return -ENOMEM; vm_dev->vdev.dev.parent = &pdev->dev; vm_dev->vdev.dev.release = virtio_mmio_release_dev; @@ -535,17 +533,14 @@ static int virtio_mmio_probe(struct platform_device *pdev) spin_lock_init(&vm_dev->lock); vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem)); - if (vm_dev->base == NULL) { - rc = -EFAULT; - goto free_vmdev; - } + if (vm_dev->base == NULL) + return -EFAULT; /* Check magic value */ magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE); if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) { dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic); - rc = -ENODEV; - goto unmap; + return -ENODEV; } /* Check device version */ @@ -553,8 +548,7 @@ static int virtio_mmio_probe(struct platform_device *pdev) if (vm_dev->version < 1 || vm_dev->version > 2) { dev_err(&pdev->dev, "Version %ld not supported!\n", vm_dev->version); - rc = -ENXIO; - goto unmap; + return -ENXIO; } vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID); @@ -563,8 +557,7 @@ static int virtio_mmio_probe(struct platform_device *pdev) * virtio-mmio device with an ID 0 is a (dummy) placeholder * with no function. End probing now with no error reported. */ - rc = -ENODEV; - goto unmap; + return -ENODEV; } vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID); @@ -590,33 +583,15 @@ static int virtio_mmio_probe(struct platform_device *pdev) platform_set_drvdata(pdev, vm_dev); rc = register_virtio_device(&vm_dev->vdev); - if (rc) { - iounmap(vm_dev->base); - devm_release_mem_region(&pdev->dev, mem->start, - resource_size(mem)); + if (rc) put_device(&vm_dev->vdev.dev); - } - return rc; -unmap: - iounmap(vm_dev->base); -free_mem: - devm_release_mem_region(&pdev->dev, mem->start, - resource_size(mem)); -free_vmdev: - devm_kfree(&pdev->dev, vm_dev); + return rc; } static int virtio_mmio_remove(struct platform_device *pdev) { struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev); - struct resource *mem; - - iounmap(vm_dev->base); - mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); - if (mem) - devm_release_mem_region(&pdev->dev, mem->start, - resource_size(mem)); unregister_virtio_device(&vm_dev->vdev); return 0;