This is a note to let you know that I've just added the patch titled xen-netback: respect gnttab_map_refs()'s return value to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xen-netback-respect-gnttab_map_refs-s-return-value.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 2991397d23ec597405b116d96de3813420bdcbc3 Mon Sep 17 00:00:00 2001 From: Jan Beulich <jbeulich@xxxxxxxx> Date: Thu, 25 Feb 2021 16:35:15 +0100 Subject: xen-netback: respect gnttab_map_refs()'s return value From: Jan Beulich <jbeulich@xxxxxxxx> commit 2991397d23ec597405b116d96de3813420bdcbc3 upstream. Commit 3194a1746e8a ("xen-netback: don't "handle" error by BUG()") dropped respective a BUG_ON() without noticing that with this the variable's value wouldn't be consumed anymore. With gnttab_set_map_op() setting all status fields to a non-zero value, in case of an error no slot should have a status of GNTST_okay (zero). This is part of XSA-367. Cc: <stable@xxxxxxxxxxxxxxx> Reported-by: kernel test robot <lkp@xxxxxxxxx> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Reviewed-by: Juergen Gross <jgross@xxxxxxxx> Link: https://lore.kernel.org/r/d933f495-619a-0086-5fb4-1ec3cf81a8fc@xxxxxxxx Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/xen-netback/netback.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -1326,11 +1326,21 @@ int xenvif_tx_action(struct xenvif_queue return 0; gnttab_batch_copy(queue->tx_copy_ops, nr_cops); - if (nr_mops != 0) + if (nr_mops != 0) { ret = gnttab_map_refs(queue->tx_map_ops, NULL, queue->pages_to_map, nr_mops); + if (ret) { + unsigned int i; + + netdev_err(queue->vif->dev, "Map fail: nr %u ret %d\n", + nr_mops, ret); + for (i = 0; i < nr_mops; ++i) + WARN_ON_ONCE(queue->tx_map_ops[i].status == + GNTST_okay); + } + } work_done = xenvif_tx_submit(queue); Patches currently in stable-queue which might be from jbeulich@xxxxxxxx are queue-4.19/xen-netback-respect-gnttab_map_refs-s-return-value.patch queue-4.19/xen-gnttab-handle-p2m-update-errors-on-a-per-slot-basis.patch