• Mark Rutland's avatar
    virtio_mmio: fix devm cleanup · c2e90800
    Mark Rutland authored
    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: default avatarMark Rutland <mark.rutland@arm.com>
    Fixes: 7eb781b1 ("virtio_mmio: add cleanup for virtio_mmio_probe")
    Fixes: 25f32223 ("virtio_mmio: add cleanup for virtio_mmio_remove")
    Cc: Cornelia Huck <cohuck@redhat.com>
    Cc: Michael S. Tsirkin <mst@redhat.com>
    Cc: weiping zhang <zhangweiping@didichuxing.com>
    Cc: virtualization@lists.linux-foundation.org
    Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
    Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
    c2e90800
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