Re: Runtime failure running sh:qemu in -next due to 'sh: fix copy_from_user()'

From: Al Viro
Date: Fri Sep 16 2016 - 16:03:46 EST

On Fri, Sep 16, 2016 at 12:12:18PM -0700, Guenter Roeck wrote:
> Hi,
> I see the following runtime failure when running a 'sh' image with qemu in -next.
> [ ... ]
> sd 0:0:0:0: [sda] Attached SCSI disk
> EXT2-fs (sda): warning: mounting unchecked fs, running e2fsck is recommended
> VFS: Mounted root (ext2 filesystem) on device 8:0.
> Freeing unused kernel memory: 124K (8c48a000 - 8c4a9000)
> This architecture does not have kernel memory protection.
> random: fast init done
> Starting logging: OK
> usb 1-1: new full-speed USB device number 2 using sm501-usb
> Initializing random number generator... done.
> Starting network...
> ip: OVERRUN: Invalid argument
> ip: OVERRUN: Bad address
> ip: OVERRUN: Bad address
> ip: OVERRUN: Bad address
> ip: OVERRUN: Bad address
> [repeats until the test aborts]
> Bisect points to commit 6e050503a150 ("sh: fix copy_from_user()"). Bisect log is
> attached.

BTW, could you post your .config and information about your userland? E.g.
is that ip(8) a busybox one, etc. If it's busybox, this smells like EINVAL
and EFAULT resp. coming from recvmsg() on netlink sockets, with nothing
extraordinary in iovecs, AFAICS...