* [PATCH] iov_iter: Fix 9p virtio breakage
@ 2018-11-02 17:16 Marc Zyngier
2018-11-02 19:04 ` Al Viro
0 siblings, 1 reply; 3+ messages in thread
From: Marc Zyngier @ 2018-11-02 17:16 UTC (permalink / raw)
To: David Howells, Al Viro; +Cc: linux-kernel, Will Deacon
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.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
net/9p/trans_virtio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 91981970f542..b1d39cabf125 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -329,7 +329,7 @@ static int p9_get_mapped_pages(struct virtio_chan *chan,
if (!iov_iter_count(data))
return 0;
- if (iov_iter_is_kvec(data)) {
+ if (!iov_iter_is_kvec(data)) {
int n;
/*
* We allow only p9_max_pages pinned. We wait for the
--
2.19.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] iov_iter: Fix 9p virtio breakage
2018-11-02 17:16 [PATCH] iov_iter: Fix 9p virtio breakage Marc Zyngier
@ 2018-11-02 19:04 ` Al Viro
2018-11-03 10:19 ` Marc Zyngier
0 siblings, 1 reply; 3+ messages in thread
From: Al Viro @ 2018-11-02 19:04 UTC (permalink / raw)
To: Marc Zyngier; +Cc: David Howells, linux-kernel, Will Deacon
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.deacon@arm.com>
> Signed-off-by: Marc Zyngier <marc.zyngier@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 <viro@zeniv.linux.org.uk>
on it.
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] iov_iter: Fix 9p virtio breakage
2018-11-02 19:04 ` Al Viro
@ 2018-11-03 10:19 ` Marc Zyngier
0 siblings, 0 replies; 3+ messages in thread
From: Marc Zyngier @ 2018-11-03 10:19 UTC (permalink / raw)
To: Al Viro; +Cc: David Howells, linux-kernel, Will Deacon
On Fri, 02 Nov 2018 19:04:33 +0000,
Al Viro <viro@ZenIV.linux.org.uk> wrote:
>
> 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.deacon@arm.com>
> > Signed-off-by: Marc Zyngier <marc.zyngier@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 <viro@zeniv.linux.org.uk>
>
> on it.
Now sent to Linus with your Ack.
Cheers,
M.
--
Jazz is not dead, it just smell funny.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2018-11-03 10:19 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-11-02 17:16 [PATCH] iov_iter: Fix 9p virtio breakage Marc Zyngier
2018-11-02 19:04 ` Al Viro
2018-11-03 10:19 ` Marc Zyngier
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).