[PATCH net v2 1/3] net: cap tx_queue_len at S16_MAX to prevent oversized ring allocations

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* [PATCH net v2 1/3] net: cap tx_queue_len at S16_MAX to prevent oversized ring allocations
@ 2026-09-02 21:29 Jamal Hadi Salim
  2026-09-02 21:29 ` [PATCH net v2 0/3] " Jamal Hadi Salim
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Jamal Hadi Salim @ 2026-09-02 21:29 UTC (permalink / raw)
  To: netdev
  Cc: Jamal Hadi Salim, stable, Jiri Pirko, David S . Miller,
	Eric Dumazet, Jakub Kicinski, Paolo Abeni, Simon Horman,
	Donald Hunter, Vega, Victor Nogueira

Several subsystems allocate ring buffers sized by dev->tx_queue_len
with no upper bound. An unprivileged user (via unshare -Urn) can set a
huge tx_queue_len and exhaust global memory with ring allocations:

- pfifo_fast: pfifo_fast_init() and pfifo_fast_change_tx_queue_len()
  allocate 3 skb_array rings of tx_queue_len entries each.
- tun: tun_queue_resize() and the queue-attach path resize ptr_rings
  to tx_queue_len on the NETDEV_CHANGE_TX_QUEUE_LEN notifier.
- tap (macvtap/ipvtap): tap_queue_resize() and tap_init() resize/init
  ptr_rings to tx_queue_len on the same notifier.

netif_change_tx_queue_len() is the single entry point for IFLA_TXQLEN,
sysfs, and the SIOCSIFTXQLEN ioctl. Cap new_len at S16_MAX (32767)
there so the oversized value is rejected at set time. This takes
effect whether the device is up or down, before dev->tx_queue_len is
written, before any notifier fires, and before any ring is allocated.
The "> S16_MAX" check also subsumes the previous unsigned-long
truncation test, and a negative ifr_qlen from the ioctl lands far
above the cap after conversion, so both old failure modes are covered
by the one comparison.

tx_queue_len is ambigious: both a per-ring sizing multiplier and a
default queue-length/limit knob for consumers that allocate
nothing at set time (pfifo/bfifo/gred/plug/sfb limits, htb
direct_qlen, qfq max_classes, teql). 32767 is chosen as the largest
value NLA_POLICY_FULL_RANGE can express for the u32 IFLA_TXQLEN
policy in patch 2/3 while staying a legitimate queue length on
high-BDP paths; the ring-memory trade-off of a shared knob is
disclosed below.

Conditions to recreate the bug:
- CONFIG_NET_SCHED=y, CONFIG_VETH=y, CONFIG_USER_NS=y, CONFIG_NET_NS=y.
- Unprivileged user in a fresh user+net namespace (unshare -Urn).
- pfifo_fast: create veth pairs, set tx_queue_len to 500000, attach
  mq+pfifo_fast. ~28 iterations OOMs a 2GB guest.
- tun: create 50 tun devices with IFF_MULTI_QUEUE, set tx_queue_len to
  500000, open 8 queues each. ~1.6GB of ptr_ring allocations OOMs a
  512MB guest.
- tap: same as tun with IFF_TAP. ~960MB OOMs a 512MB guest.
- On the fixed kernel the oversized tx_queue_len is rejected with
  -ERANGE at set time (all four paths: RTM_SETLINK, RTM_NEWLINK
  create, sysfs, ioctl - the latter two via this check, the former
  two via this check and the 2/3 parse policy respectively).

Fixes: 6a643ddb5624 ("net: introduce helper dev_change_tx_queue_len()")
Reported-by: Vega <vega@nebusec.ai>
Closes: https://lore.kernel.org/netdev/20260828121902.66837-1-jhs@mojatatu.com/
Tested-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
---
 net/core/dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 38336858c168..1d3fc0a268a5 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -9982,7 +9982,7 @@ int netif_change_tx_queue_len(struct net_device *dev, unsigned long new_len)
 	unsigned int orig_len = dev->tx_queue_len;
 	int res;

-	if (new_len != (unsigned int)new_len)
+	if (new_len > S16_MAX)
 		return -ERANGE;

 	if (new_len != orig_len) {
-- 
2.43.0

^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [PATCH net v2 0/3] net: cap tx_queue_len at S16_MAX to prevent oversized ring allocations
  2026-09-02 21:29 [PATCH net v2 1/3] net: cap tx_queue_len at S16_MAX to prevent oversized ring allocations Jamal Hadi Salim
@ 2026-09-02 21:29 ` Jamal Hadi Salim
  2026-09-02 21:29 ` [PATCH net v2 2/3] net: reject oversized tx_queue_len at netlink parse time Jamal Hadi Salim
  2026-09-02 21:29 ` [PATCH net v2 3/3] selftests: tc-testing: add tx_queue_len cap regression tests Jamal Hadi Salim
  2 siblings, 0 replies; 4+ messages in thread
From: Jamal Hadi Salim @ 2026-09-02 21:29 UTC (permalink / raw)
  To: netdev
  Cc: Jamal Hadi Salim, stable, Jiri Pirko, David S . Miller,
	Eric Dumazet, Jakub Kicinski, Paolo Abeni, Simon Horman,
	Donald Hunter, Vega, Victor Nogueira

An unprivileged user (via unshare -Urn) can set a huge tx_queue_len
and exhaust global memory through ring allocations sized from it
(pfifo_fast skb_arrays, tun/tap ptr_rings).
The reproducer from vega@nebusec.ai set the following params for
illustration: txqlen of 500000 -> ~32 GiB/ring attempts, 1.6 GB tun,
~960 MB tap. Gets worse when you consider qdiscs like mq.

What we fix: every path an unprivileged user can use to install
an oversized tx_queue_len is rejected with -ERANGE before any ring is
allocated; per-ring memory is bounded at 256 KiB.

This is for you sashikos: What we deliberately _do not fix_
bound the NUMBER of rings. With the cap in place the worst case moves
from "one knob" to the aggregate of ring x queues x devices, example:

  ip link add v0 numtxqueues 4096 txqueuelen 32767 type veth
  tc qdisc add dev v0 root mq
    -> 4096 * 3 * 32767 * 8 = ~3.0 GiB (one command)
  50 tun devices x 256 queues x 32767 x 8 = ~3.1 GiB

Unfortunately tx_queue_len is a bit ambigious in meaning:
In some cases it means a ring size (which is pre-allocated, ex:
tun, tap, and pfifo_fast); a cap of 4096 seems reasonable here.
but in other cases it is used to indicate a queue limit ex:
the qdisc consumers that allocate nothing (pfifo/bfifo/gred/plug/sfb,
htb direct_qlen, qfq, teql). 32767 is a legitimate high-BDP queue
length, so we are going to keep that value.

Getting back to you sashikos, after this is merged and shows up
in net-next we will send followup patches as follows:
this series is not misread as "closes the OOM class"):

a) Per-site ring limits at six identified locations
    - pfifo_fast init/resize,
    - tun attach/resize,
    - tap minor/resize)

   if you can spot more in your review we will take care of those as well.

b) memcg accounting (GFP_KERNEL_ACCOUNT) for those ring
   allocations: contains a memcg-limited container's ring memory.
   Not GFP_KERNEL_ACCOUNT has no effect on the unshare attacker
   but will protect against containers  (memory.max in its cgroup)

Patches:
--------

  1/3 net: cap tx_queue_len at S16_MAX in netif_change_tx_queue_len()
      (netlink set, sysfs, SIOCSIFTXQLEN choke point)
  2/3 net: reject oversized tx_queue_len at netlink parse time
      (IFLA_TXQLEN policy: closes the create path + veth peer nest)
  3/3 selftests: tdc regression tests (netlink, sysfs, create paths)

Changes:
--------
v1 -> v2:
- new patch 2/3: close the device-creation path (Jakub Kicinski
  flagged that rtnl_create_link() bypasses the cap)
- rationale reworded: the 32767 ceiling citing NLA u32 range
  policy can express (s16 bounds), replacing the invalid virtio
  ring-depth claim
- rebuilt tdc coverage (sysfs path now tested; nondeterministic
  resize-rollback case dropped)

Sashiko v1 review links:
https://sashiko.dev/#/patchset/20260828121902.66837-1-jhs@mojatatu.com
https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260828121902.66837-1-jhs@mojatatu.com

v1: https://lore.kernel.org/netdev/20260828121902.66837-1-jhs@mojatatu.com/

Jamal Hadi Salim (3):
  net: cap tx_queue_len at S16_MAX to prevent oversized ring
    allocations
  net: reject oversized tx_queue_len at netlink parse time
  selftests: tc-testing: add tx_queue_len cap regression tests

 .../tc-testing/tc-tests/qdiscs/pfifo_fast.json | 209 +++++++++++++++++-
 net/core/dev.c                                 |   2 +-
 net/core/rtnetlink.c                           |   9 +-
 3 files changed, 211 insertions(+), 2 deletions(-)

-- 
2.43.0

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH net v2 2/3] net: reject oversized tx_queue_len at netlink parse time
  2026-09-02 21:29 [PATCH net v2 1/3] net: cap tx_queue_len at S16_MAX to prevent oversized ring allocations Jamal Hadi Salim
  2026-09-02 21:29 ` [PATCH net v2 0/3] " Jamal Hadi Salim
@ 2026-09-02 21:29 ` Jamal Hadi Salim
  2026-09-02 21:29 ` [PATCH net v2 3/3] selftests: tc-testing: add tx_queue_len cap regression tests Jamal Hadi Salim
  2 siblings, 0 replies; 4+ messages in thread
From: Jamal Hadi Salim @ 2026-09-02 21:29 UTC (permalink / raw)
  To: netdev
  Cc: Jamal Hadi Salim, stable, Jiri Pirko, David S . Miller,
	Eric Dumazet, Jakub Kicinski, Paolo Abeni, Simon Horman,
	Donald Hunter, Cong Wang, Shuah Khan, Vega, Victor Nogueira

rtnl_create_link() assigns IFLA_TXQLEN directly to dev->tx_queue_len
without going through netif_change_tx_queue_len(), so a device created
with "ip link add ... txqueuelen 500000" bypasses the S16_MAX cap and
still triggers the oversized ring allocations in pfifo_fast, tun and
tap. The veth peer nest (rtnl_nla_parse_ifinfomsg()) and the
RTM_NEWLINK-on-existing-device path reach the same sinks.

Enforce the cap in ifla_policy instead: IFLA_TXQLEN becomes
NLA_POLICY_FULL_RANGE(NLA_U32, &txqlen_range) with
txqlen_range = { .min = 0, .max = S16_MAX }. All netlink consumers
parse against this policy - rtnl_setlink(), rtnl_newlink() (create
and change), and the veth peer nest - so every netlink path is capped
at parse time and rejects the attribute with -ERANGE plus a proper
"integer out of range" extack message before any device state is
modified (the RTM_SETLINK half-application wart is gone with it).

Document the bound in the rt-link.yaml netlink spec.

Conditions to recreate the bug:
- CONFIG_NET_SCHED=y, CONFIG_VETH=y, CONFIG_USER_NS=y, CONFIG_NET_NS=y.
- Unprivileged user in a fresh user+net namespace (unshare -Urn):
  ip link add v0 txqueuelen 500000 type veth peer name v1
  -> on the fixed kernel this is rejected with -ERANGE ("integer out
  of range" extack) instead of installing an oversized tx_queue_len
  that later inflates pfifo_fast/tun/tap ring allocations.
- ip link set v0 txqueuelen 500000 is likewise rejected at parse time.

Fixes: 38f7b870d4a6 ("[RTNETLINK]: Link creation API")
Reported-by: Vega <vega@nebusec.ai>
Tested-by: Victor Nogueira <victor@mojatatu.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
---
 Documentation/netlink/specs/rt-link.yaml | 2 ++
 net/core/rtnetlink.c                     | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/Documentation/netlink/specs/rt-link.yaml b/Documentation/netlink/specs/rt-link.yaml
index b80c2ac3ac31..99f6fba456cc 100644
--- a/Documentation/netlink/specs/rt-link.yaml
+++ b/Documentation/netlink/specs/rt-link.yaml
@@ -898,6 +898,8 @@ attribute-sets:
       -
         name: txqlen
         type: u32
+        checks:
+          max: 32767
       -
         name: map
         type: binary
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 81c5a6104dea..9ea4ff9c1e29 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2285,7 +2285,12 @@ int rtnl_unicast(struct sk_buff *skb, struct net *net, u32 pid)
 	rcu_read_unlock();
 nla_put_failure:
 	nlmsg_cancel(skb, nlh);
 	return -EMSGSIZE;
 }
 
+static const struct netlink_range_validation txqlen_range = {
+	.min = 0,
+	.max = S16_MAX,
+};
+
 static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
@@ -2297,7 +2302,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
 	[IFLA_LINK]		= { .type = NLA_U32 },
 	[IFLA_MASTER]		= { .type = NLA_U32 },
 	[IFLA_CARRIER]		= { .type = NLA_U8 },
-	[IFLA_TXQLEN]		= { .type = NLA_U32 },
+	[IFLA_TXQLEN]		= NLA_POLICY_FULL_RANGE(NLA_U32, &txqlen_range),
 	[IFLA_WEIGHT]		= { .type = NLA_U32 },
 	[IFLA_OPERSTATE]	= { .type = NLA_U8 },
 	[IFLA_LINKMODE]		= { .type = NLA_U8 },
-- 
2.43.0

^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [PATCH net v2 3/3] selftests: tc-testing: add tx_queue_len cap regression tests
  2026-09-02 21:29 [PATCH net v2 1/3] net: cap tx_queue_len at S16_MAX to prevent oversized ring allocations Jamal Hadi Salim
  2026-09-02 21:29 ` [PATCH net v2 0/3] " Jamal Hadi Salim
  2026-09-02 21:29 ` [PATCH net v2 2/3] net: reject oversized tx_queue_len at netlink parse time Jamal Hadi Salim
@ 2026-09-02 21:29 ` Jamal Hadi Salim
  2 siblings, 0 replies; 4+ messages in thread
From: Jamal Hadi Salim @ 2026-09-02 21:29 UTC (permalink / raw)
  To: netdev
  Cc: Jamal Hadi Salim, stable, Jiri Pirko, David S . Miller,
	Eric Dumazet, Jakub Kicinski, Paolo Abeni, Simon Horman,
	Donald Hunter, Shuah Khan, Vega, Victor Nogueira

Add nine test cases for the S16_MAX tx_queue_len cap to the
pfifo_fast suite. Netlink cases exercise the ifla_policy bound
(2/3); the two new sysfs cases exercise the netif_change_tx_queue_len()
choke point that 1/3 owns (SIOCSIFTXQLEN shares it; the ioctl is not
portably reachable from tdc):

- dbe3: set txqueuelen 32767 (S16_MAX) - accepted, pins the exact
  boundary value.
- b50e: set txqueuelen 32768 - rejected with -ERANGE.
- 40f8: write 32768 to /sys/class/net/*/tx_queue_len - rejected
  (covers patch 1/3 directly; netlink cannot reach this path).
- 4b6e: write 32767 via sysfs - accepted, boundary positive control
  for the patch-1 path.
- b90d: create a dummy with txqueuelen 32767 - accepted.
- 57ab: create a dummy with txqueuelen 32768 - rejected at netlink
  parse time.
- e777: create a dummy with txqueuelen 500000 - rejected (the v1
  bypass path flagged by review).
- 31ac: create a veth with an oversized txqueuelen on the peer nest -
  rejected (the peer nest is parsed against ifla_policy too).
- b567: create a veth with txqueuelen on both ends within the cap -
  accepted (positive control for the peer nest).

The three negative-creation verifies assert device absence
("ip -o link show" must not contain the device), not merely absence
of a qlen pattern - the device does not exist when creation fails, so
the exit code carries the signal and the verify adds content.

The v1 04b5 "resize rollback" case is dropped: with the cap checked
first, netif_change_tx_queue_len() returns -ERANGE before the write,
the notifier or any qdisc resize, so the case exercised no resize and
no rollback. It was also nondeterministic: pre-patch, the resize
issues three ~11 MB kvmallocs for qlen 500000 which normally succeed,
so the case passed on an unfixed kernel only under memory pressure -
its outcome depended on the test host's free memory.

Test commands run inside the netns, but nsPlugin creates the veth
peer in the root namespace, so the teardown deletes the in-ns end
only; deleting the peer via the pair is implicit.

Note: iproute2 treats "txqueuelen" appearing after "type X" as a
link-type attribute and silently drops it, so the creation cases
place it before "type" to actually reach the kernel.

Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
---
Changes since v1:
- new patch: rebuilt tdc coverage for the v2 series (drop
  nondeterministic 04b5; boundary pair + create-path + peer-nest)

Internal review (i1) changes, 2026-09-02:
- add sysfs coverage (40f8/4b6e): the seven v2 cases all drive
  netlink and exercise only 2/3; patch 1/3 owns sysfs+ioctl
- strengthen the three negative-creation verifies (57ab/e777/31ac):
  assert device absence instead of pattern absence on a nonexistent
  device (vacuous before)
- fix the Cc: header (recipients were folded into To:)
- drop the no-op "$IP link del dev $DEV0" teardown (peer lives in
  the root namespace; deleting $DEV1 removes the pair)
- subject prefix: selftests/tc-testing (conventional for the dir)
---
 .../selftests/tc-testing/tc-tests/qdiscs/pfifo_fast.json | 204 ++++++++++++
 1 file changed, 204 insertions(+)

diff --git a/tools/testing/selftests/tc-testing/tc-tests/qdiscs/pfifo_fast.json b/tools/testing/selftests/tc-testing/tc-tests/qdiscs/pfifo_fast.json
index 30da27fe8806..a6e25e76ecb1 100644
--- a/tools/testing/selftests/tc-testing/tc-tests/qdiscs/pfifo_fast.json
+++ b/tools/testing/selftests/tc-testing/tc-tests/qdiscs/pfifo_fast.json
@@ -105,5 +105,209 @@
         "teardown": [
             "$TC qdisc del dev $DUMMY handle 1: root"
         ]
+    },
+    {
+        "id": "dbe3",
+        "name": "Set tx_queue_len to S16_MAX boundary (32767 accepted)",
+        "category": [
+            "qdisc",
+            "pfifo_fast"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [],
+        "cmdUnderTest": "$IP link set dev $DUMMY txqueuelen 32767",
+        "expExitCode": "0",
+        "verifyCmd": "$IP link show dev $DUMMY",
+        "matchPattern": "qlen 32767$",
+        "matchCount": "1",
+        "teardown": []
+    },
+    {
+        "id": "b50e",
+        "name": "Reject tx_queue_len above S16_MAX at set time (32768)",
+        "category": [
+            "qdisc",
+            "pfifo_fast"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [],
+        "cmdUnderTest": "$IP link set dev $DUMMY txqueuelen 32768",
+        "expExitCode": "2",
+        "verifyCmd": "$IP link show dev $DUMMY",
+        "matchPattern": "qlen 1000$",
+        "matchCount": "1",
+        "teardown": []
+    },
+    {
+        "id": "40f8",
+        "name": "Reject tx_queue_len above S16_MAX via sysfs (32768)",
+        "category": [
+            "qdisc",
+            "pfifo_fast"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [],
+        "cmdUnderTest": "sh -c 'echo 32768 > /sys/class/net/$DUMMY/tx_queue_len'",
+        "expExitCode": "1",
+        "verifyCmd": "$IP link show dev $DUMMY",
+        "matchPattern": "qlen 1000$",
+        "matchCount": "1",
+        "teardown": []
+    },
+    {
+        "id": "4b6e",
+        "name": "Set tx_queue_len to S16_MAX via sysfs (32767 accepted)",
+        "category": [
+            "qdisc",
+            "pfifo_fast"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [],
+        "cmdUnderTest": "sh -c 'echo 32767 > /sys/class/net/$DUMMY/tx_queue_len'",
+        "expExitCode": "0",
+        "verifyCmd": "$IP link show dev $DUMMY",
+        "matchPattern": "qlen 32767$",
+        "matchCount": "1",
+        "teardown": []
+    },
+    {
+        "id": "b90d",
+        "name": "Create device with tx_queue_len at S16_MAX boundary (32767 accepted)",
+        "category": [
+            "qdisc",
+            "pfifo_fast"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            [
+                "$IP link del dev $DUMMY",
+                0,
+                1
+            ]
+        ],
+        "cmdUnderTest": "$IP link add dev $DUMMY txqueuelen 32767 type dummy",
+        "expExitCode": "0",
+        "verifyCmd": "$IP link show dev $DUMMY",
+        "matchPattern": "qlen 32767$",
+        "matchCount": "1",
+        "teardown": [
+            [
+                "$IP link del dev $DUMMY",
+                0,
+                1
+            ]
+        ]
+    },
+    {
+        "id": "57ab",
+        "name": "Reject creating device with tx_queue_len above S16_MAX (32768)",
+        "category": [
+            "qdisc",
+            "pfifo_fast"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            [
+                "$IP link del dev $DUMMY",
+                0,
+                1
+            ]
+        ],
+        "cmdUnderTest": "$IP link add dev $DUMMY txqueuelen 32768 type dummy",
+        "expExitCode": "2",
+        "verifyCmd": "$IP -o link show",
+        "matchPattern": "^[0-9]+: $DUMMY",
+        "matchCount": "0",
+        "teardown": []
+    },
+    {
+        "id": "e777",
+        "name": "Reject creating device with oversized tx_queue_len (500000)",
+        "category": [
+            "qdisc",
+            "pfifo_fast"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            [
+                "$IP link del dev $DUMMY",
+                0,
+                1
+            ]
+        ],
+        "cmdUnderTest": "$IP link add dev $DUMMY txqueuelen 500000 type dummy",
+        "expExitCode": "2",
+        "verifyCmd": "$IP -o link show",
+        "matchPattern": "^[0-9]+: $DUMMY",
+        "matchCount": "0",
+        "teardown": []
+    },
+    {
+        "id": "31ac",
+        "name": "Reject veth peer nest tx_queue_len above S16_MAX at create",
+        "category": [
+            "qdisc",
+            "pfifo_fast"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            [
+                "$IP link del dev $DEV1",
+                0,
+                1
+            ]
+        ],
+        "cmdUnderTest": "$IP link add dev $DEV1 type veth peer name $DEV0 txqueuelen 500000",
+        "expExitCode": "2",
+        "verifyCmd": "$IP -o link show",
+        "matchPattern": "^[0-9]+: $DEV1",
+        "matchCount": "0",
+        "teardown": []
+    },
+    {
+        "id": "b567",
+        "name": "Accept veth peer nest tx_queue_len within S16_MAX",
+        "category": [
+            "qdisc",
+            "pfifo_fast"
+        ],
+        "plugins": {
+            "requires": "nsPlugin"
+        },
+        "setup": [
+            [
+                "$IP link del dev $DEV1",
+                0,
+                1
+            ]
+        ],
+        "cmdUnderTest": "$IP link add dev $DEV1 txqueuelen 100 type veth peer name $DEV0 txqueuelen 200",
+        "expExitCode": "0",
+        "verifyCmd": "$IP link show",
+        "matchPattern": "qlen (100|200)$",
+        "matchCount": "2",
+        "teardown": [
+            [
+                "$IP link del dev $DEV0",
+                0,
+                1
+            ]
+        ]
     }
 ]

^ permalink raw reply related	[flat|nested] 4+ messages in thread

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2026-09-02 21:29 [PATCH net v2 1/3] net: cap tx_queue_len at S16_MAX to prevent oversized ring allocations Jamal Hadi Salim
2026-09-02 21:29 ` [PATCH net v2 0/3] " Jamal Hadi Salim
2026-09-02 21:29 ` [PATCH net v2 2/3] net: reject oversized tx_queue_len at netlink parse time Jamal Hadi Salim
2026-09-02 21:29 ` [PATCH net v2 3/3] selftests: tc-testing: add tx_queue_len cap regression tests Jamal Hadi Salim

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