On Fri, Nov 02, 2018 at 05:16:51PM +0000, Marc Zyngier wrote:
> When switching to the new iovec accessors, a negation got subtly
> dropped, leading to 9p being remarkably broken (here with kvmtool):
>
> [ 7.430941] VFS: Mounted root (9p filesystem) on device 0:15.
> [ 7.432080] devtmpfs: mounted
> [ 7.432717] Freeing unused kernel memory: 1344K
> [ 7.433658] Run /virt/init as init process
> Warning: unable to translate guest address 0x7e00902ff000 to host
> Warning: unable to translate guest address 0x7e00902fefc0 to host
> Warning: unable to translate guest address 0x7e00902ff000 to host
> Warning: unable to translate guest address 0x7e008febef80 to host
> Warning: unable to translate guest address 0x7e008febf000 to host
> Warning: unable to translate guest address 0x7e008febef00 to host
> Warning: unable to translate guest address 0x7e008febf000 to host
> [ 7.436376] Kernel panic - not syncing: Requested init /virt/init failed
> (error -8).
> [ 7.437554] CPU: 29 PID: 1 Comm: swapper/0 Not tainted
> 4.19.0-rc8-02267-g00e23707442a #291
> [ 7.439006] Hardware name: linux,dummy-virt (DT)
> [ 7.439902] Call trace:
> [ 7.440387] dump_backtrace+0x0/0x148
> [ 7.441104] show_stack+0x14/0x20
> [ 7.441768] dump_stack+0x90/0xb4
> [ 7.442425] panic+0x120/0x27c
> [ 7.443036] kernel_init+0xa4/0x100
> [ 7.443725] ret_from_fork+0x10/0x18
> [ 7.444444] SMP: stopping secondary CPUs
> [ 7.445391] Kernel Offset: disabled
> [ 7.446169] CPU features: 0x0,23000438
> [ 7.446974] Memory Limit: none
> [ 7.447645] ---[ end Kernel panic - not syncing: Requested init /virt/init
> failed (error -8). ]---
>
> Restoring the missing "!" brings the guest back to life.
>
> Fixes: 00e23707442a ("iov_iter: Use accessor function")
> Reported-by: Will Deacon <will.dea...@arm.com>
> Signed-off-by: Marc Zyngier <marc.zyng...@arm.com>
ACK. Do you want me to take it via vfs.git? Or might as well
send directly to Linus, with
Acked-by Al Viro <v...@zeniv.linux.org.uk>
on it.
