From: Vineeth Vijayan vneethv@linux.ibm.com
commit a4751f157c194431fae9e9c493f456df8272b871 upstream.
Check the validity of subchanel before reading other fields in the schib.
Fixes: d3683c055212 ("s390/cio: add dev_busid sysfs entry for each subchannel") CC: stable@vger.kernel.org Reported-by: Cornelia Huck cohuck@redhat.com Signed-off-by: Vineeth Vijayan vneethv@linux.ibm.com Reviewed-by: Cornelia Huck cohuck@redhat.com Link: https://lore.kernel.org/r/20211105154451.847288-1-vneethv@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/s390/cio/css.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/s390/cio/css.c +++ b/drivers/s390/cio/css.c @@ -337,8 +337,8 @@ static ssize_t dev_busid_show(struct dev struct subchannel *sch = to_subchannel(dev); struct pmcw *pmcw = &sch->schib.pmcw;
- if ((pmcw->st == SUBCHANNEL_TYPE_IO || - pmcw->st == SUBCHANNEL_TYPE_MSG) && pmcw->dnv) + if ((pmcw->st == SUBCHANNEL_TYPE_IO && pmcw->dnv) || + (pmcw->st == SUBCHANNEL_TYPE_MSG && pmcw->w)) return sysfs_emit(buf, "0.%x.%04x\n", sch->schid.ssid, pmcw->dev); else