This is a note to let you know that I've just added the patch titled
s390/qeth: fix double-free on IP add/remove race
to the 4.14-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:
s390-qeth-fix-double-free-on-ip-add-remove-race.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Mar 6 19:02:12 PST 2018
From: Julian Wiedmann <jwi@xxxxxxxxxxxxxxxxxx>
Date: Tue, 27 Feb 2018 18:58:14 +0100
Subject: s390/qeth: fix double-free on IP add/remove race
From: Julian Wiedmann <jwi@xxxxxxxxxxxxxxxxxx>
[ Upstream commit 14d066c3531a87f727968cacd85bd95c75f59843 ]
Registering an IPv4 address with the HW takes quite a while, so we
temporarily drop the ip_htable lock. Any concurrent add/remove of the
same IP adjusts the IP's use count, and (on remove) is then blocked by
addr->in_progress.
After the register call has completed, we check the use count for
concurrently attempted add/remove calls - and possibly straight-away
deregister the IP again. This happens via l3_delete_ip(), which
1) looks up the queried IP in the htable (getting a reference to the
*same* queried object),
2) deregisters the IP from the HW, and
3) frees the IP object.
The caller in l3_add_ip() then does a second free on the same object.
For this case, skip all the extra checks and lookups in l3_delete_ip()
and just deregister & free the IP object ourselves.
Fixes: 5f78e29ceebf ("qeth: optimize IP handling in rx_mode callback")
Signed-off-by: Julian Wiedmann <jwi@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/s390/net/qeth_l3_main.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -319,7 +319,8 @@ int qeth_l3_add_ip(struct qeth_card *car
(rc == IPA_RC_LAN_OFFLINE)) {
addr->disp_flag = QETH_DISP_ADDR_DO_NOTHING;
if (addr->ref_counter < 1) {
- qeth_l3_delete_ip(card, addr);
+ qeth_l3_deregister_addr_entry(card, addr);
+ hash_del(&addr->hnode);
kfree(addr);
}
} else {
Patches currently in stable-queue which might be from jwi@xxxxxxxxxxxxxxxxxx are
queue-4.14/s390-qeth-fix-setip-command-handling.patch
queue-4.14/s390-qeth-fix-ip-address-lookup-for-l3-devices.patch
queue-4.14/s390-qeth-fix-ipa-command-submission-race.patch
queue-4.14/revert-s390-qeth-fix-using-of-ref-counter-for-rxip-addresses.patch
queue-4.14/s390-qeth-fix-overestimated-count-of-buffer-elements.patch
queue-4.14/s390-qeth-fix-double-free-on-ip-add-remove-race.patch
queue-4.14/s390-qeth-fix-ip-removal-on-offline-cards.patch
queue-4.14/s390-qeth-fix-underestimated-count-of-buffer-elements.patch