diff options
| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2018-09-06 13:26:08 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-10-10 08:53:22 +0200 |
| commit | 9e72ba07a630c03e9a5878a45e504b11609596c3 (patch) | |
| tree | 90a20280468bfc96ce12fd630faa2afade89b227 | |
| parent | 3466db7bf72e80f1d5fe4aaf22fb1f9e59abb538 (diff) | |
xen/manage: don't complain about an empty value in control/sysrq node
[ Upstream commit 87dffe86d406bee8782cac2db035acb9a28620a7 ]
When guest receives a sysrq request from the host it acknowledges it by
writing '\0' to control/sysrq xenstore node. This, however, make xenstore
watch fire again but xenbus_scanf() fails to parse empty value with "%c"
format string:
sysrq: SysRq : Emergency Sync
Emergency Sync complete
xen:manage: Error -34 reading sysrq code in control/sysrq
Ignore -ERANGE the same way we already ignore -ENOENT, empty value in
control/sysrq is totally legal.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/xen/manage.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c index 7abaaa5f0f67..abd49bc7c460 100644 --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -282,9 +282,11 @@ static void sysrq_handler(struct xenbus_watch *watch, const char **vec, /* * The Xenstore watch fires directly after registering it and * after a suspend/resume cycle. So ENOENT is no error but - * might happen in those cases. + * might happen in those cases. ERANGE is observed when we get + * an empty value (''), this happens when we acknowledge the + * request by writing '\0' below. */ - if (err != -ENOENT) + if (err != -ENOENT && err != -ERANGE) pr_err("Error %d reading sysrq code in control/sysrq\n", err); xenbus_transaction_end(xbt, 1); |