On Tue, Dec 12, 2017 at 02:09:52PM +0100, Cornelia Huck wrote: > On Tue, 12 Dec 2017 12:53:02 +0000 > Mark Rutland <mark.rutland@xxxxxxx> wrote: > > > Recent rework of the virtio_mmio probe path 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 failure 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 > > Oops. > > > 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. We only need to ensure that we call put_device() if a call to > > register_virtio_device() fails. > > OK, that was the subtility I obviously missed. Reading through the > code, this seems correct (although I find the infrastructure a bit > unintuitive). No worries. > Shouldn't the cleanup in _remove() then be removed as well? Ah, I'd missed that. I believe that can be removed, yes. Should I spin a v2 with that folded in? Thanks, Mark. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
