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| author |   Vitaly Kuznetsov <vkuznets@redhat.com> | 2018-09-06 13:26:08 +0200 |
|---|---|---|
| committer |   Boris Ostrovsky <boris.ostrovsky@oracle.com> | 2018-09-14 08:51:10 -0400 |
| commit | 87dffe86d406bee8782cac2db035acb9a28620a7 (patch) | |
| tree | ee0ab909b1280f621dad908ac4a65f2765ca9371 /drivers/xen/manage.c | |
| parent | Linux 4.19-rc3 (diff) | |
| download | linux-dev-87dffe86d406bee8782cac2db035acb9a28620a7.tar.xz linux-dev-87dffe86d406bee8782cac2db035acb9a28620a7.zip | |
xen/manage: don't complain about an empty value in control/sysrq node
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>
Diffstat (limited to 'drivers/xen/manage.c')
| -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 c93d8ef8df34..5bb01a62f214 100644 --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -280,9 +280,11 @@ static void sysrq_handler(struct xenbus_watch *watch, const char *path, /* * 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); |