On Tuesday, January 20, 2015 10:48:58 PM Sasha Levin wrote:
> On 01/19/2015 03:08 PM, Paul Moore wrote:
> > There are several areas in the kernel that create temporary filename
> >
> > objects using the following pattern:
> > int func(const char *name)
> > {
> >
> > struct filename *file = { .name = name };
> > ...
> > return 0;
> >
> > }
> >
> > ... which for the most part works okay, but it causes havoc within the
> > audit subsystem as the filename object does not persist beyond the
> > lifetime of the function. This patch converts all of these temporary
> > filename objects into proper filename objects using getname_kernel()
> > and putname() which ensure that the filename object persists until the
> > audit subsystem is finished with it.
>
> Hi Paul,
>
> With this patch (bisected) my vm fails to boot with a virtio-9p rootfs:
>
> [ 27.313687] fa00 2097152 vda driver: virtio_blk
> [ 27.314218] 103:00000 8192 sda driver: sd
> [ 27.314714] DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify explicit
> textual name for "root=" boot option. [ 27.315963] Kernel panic - not
> syncing: VFS: Unable to mount root fs on unknown-block(0,0) [ 27.316885]
> CPU: 29 PID: 1 Comm: swapper/0 Not tainted
> 3.19.0-rc5-next-20150120-sasha-00053-gb2e3c55-dirty #1772 [ 27.316885]
> ffffffffffffffff ffff88005cb8bd28 ffffffffb14522b5 000000000000004e [
> 27.316885] ffffffffb26d4950 ffff88005cb8bda8 ffffffffb144c298
> ffff88005cb8bd48 [ 27.316885] ffffffff00000010 ffff88005cb8bdb8
> ffff88005cb8bd58 fffffffffffffffe [ 27.316885] Call Trace:
> [ 27.316885] [<ffffffffb14522b5>] dump_stack+0x4f/0x7b
> [ 27.316885] [<ffffffffb144c298>] panic+0xd2/0x216
> [ 27.316885] [<ffffffffb431558b>] mount_block_root+0x18b/0x244
> [ 27.316885] [<ffffffffb43158ae>] mount_root+0x128/0x133
> [ 27.316885] [<ffffffffb4315a1b>] prepare_namespace+0x162/0x19b
> [ 27.316885] [<ffffffffb4315223>] kernel_init_freeable+0x285/0x29a
> [ 27.316885] [<ffffffffb14472b0>] ? rest_init+0xd0/0xd0
> [ 27.316885] [<ffffffffb14472be>] kernel_init+0xe/0xf0
> [ 27.316885] [<ffffffffb148007c>] ret_from_fork+0x7c/0xb0
> [ 27.316885] [<ffffffffb14472b0>] ? rest_init+0xd0/0xd0
> [ 27.316885] Dumping ftrace buffer:
> [ 27.316885] (ftrace buffer empty)
> [ 27.316885] Kernel Offset: 0x2d000000 from 0xffffffff81000000 (relocation
> range: 0xffffffff80000000-0xffffffffbfffffff) [ 27.316885] Rebooting in 1
> seconds..
>
> virtio-9p is not even listed as an option now.
Thanks for reporting the problem, we're currently working on a fix:
* https://lkml.org/lkml/2015/1/20/710
--
paul moore
security @ redhat
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