<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/net/ipv6/route.c, branch linux-7.0.y</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=linux-7.0.y</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=linux-7.0.y'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2026-03-23T23:59:31+00:00</updated>
<entry>
<title>ipv6: Don't remove permanent routes with exceptions from tb6_gc_hlist.</title>
<updated>2026-03-23T23:59:31+00:00</updated>
<author>
<name>Kuniyuki Iwashima</name>
<email>kuniyu@google.com</email>
</author>
<published>2026-03-20T07:23:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=4be7b99c253f0c85a255cc1db7127ba3232dfa30'/>
<id>urn:sha1:4be7b99c253f0c85a255cc1db7127ba3232dfa30</id>
<content type='text'>
The cited commit mechanically put fib6_remove_gc_list()
just after every fib6_clean_expires() call.

When a temporary route is promoted to a permanent route,
there may already be exception routes tied to it.

If fib6_remove_gc_list() removes the route from tb6_gc_hlist,
such exception routes will no longer be aged.

Let's replace fib6_remove_gc_list() with a new helper
fib6_may_remove_gc_list() and use fib6_age_exceptions() there.

Note that net-&gt;ipv6 is only compiled when CONFIG_IPV6 is
enabled, so fib6_{add,remove,may_remove}_gc_list() are guarded.

Fixes: 5eb902b8e719 ("net/ipv6: Remove expired routes with a separated list of routes.")
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@google.com&gt;
Reviewed-by: David Ahern &lt;dsahern@kernel.org&gt;
Link: https://patch.msgid.link/20260320072317.2561779-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>net: ipv6: fix panic when IPv4 route references loopback IPv6 nexthop</title>
<updated>2026-03-05T15:53:17+00:00</updated>
<author>
<name>Jiayuan Chen</name>
<email>jiayuan.chen@shopee.com</email>
</author>
<published>2026-03-04T11:38:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=21ec92774d1536f71bdc90b0e3d052eff99cf093'/>
<id>urn:sha1:21ec92774d1536f71bdc90b0e3d052eff99cf093</id>
<content type='text'>
When a standalone IPv6 nexthop object is created with a loopback device
(e.g., "ip -6 nexthop add id 100 dev lo"), fib6_nh_init() misclassifies
it as a reject route. This is because nexthop objects have no destination
prefix (fc_dst=::), causing fib6_is_reject() to match any loopback
nexthop. The reject path skips fib_nh_common_init(), leaving
nhc_pcpu_rth_output unallocated. If an IPv4 route later references this
nexthop, __mkroute_output() dereferences NULL nhc_pcpu_rth_output and
panics.

Simplify the check in fib6_nh_init() to only match explicit reject
routes (RTF_REJECT) instead of using fib6_is_reject(). The loopback
promotion heuristic in fib6_is_reject() is handled separately by
ip6_route_info_create_nh(). After this change, the three cases behave
as follows:

1. Explicit reject route ("ip -6 route add unreachable 2001:db8::/64"):
   RTF_REJECT is set, enters reject path, skips fib_nh_common_init().
   No behavior change.

2. Implicit loopback reject route ("ip -6 route add 2001:db8::/32 dev lo"):
   RTF_REJECT is not set, takes normal path, fib_nh_common_init() is
   called. ip6_route_info_create_nh() still promotes it to reject
   afterward. nhc_pcpu_rth_output is allocated but unused, which is
   harmless.

3. Standalone nexthop object ("ip -6 nexthop add id 100 dev lo"):
   RTF_REJECT is not set, takes normal path, fib_nh_common_init() is
   called. nhc_pcpu_rth_output is properly allocated, fixing the crash
   when IPv4 routes reference this nexthop.

Suggested-by: Ido Schimmel &lt;idosch@nvidia.com&gt;
Fixes: 493ced1ac47c ("ipv4: Allow routes to use nexthop objects")
Reported-by: syzbot+334190e097a98a1b81bb@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/698f8482.a70a0220.2c38d7.00ca.GAE@google.com/T/
Signed-off-by: Jiayuan Chen &lt;jiayuan.chen@shopee.com&gt;
Reviewed-by: Ido Schimmel &lt;idosch@nvidia.com&gt;
Reviewed-by: David Ahern &lt;dsahern@kernel.org&gt;
Link: https://patch.msgid.link/20260304113817.294966-2-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>ipv6: fix NULL pointer deref in ip6_rt_get_dev_rcu()</title>
<updated>2026-03-04T01:14:48+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2026-03-01T19:45:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=2ffb4f5c2ccb2fa1c049dd11899aee7967deef5a'/>
<id>urn:sha1:2ffb4f5c2ccb2fa1c049dd11899aee7967deef5a</id>
<content type='text'>
l3mdev_master_dev_rcu() can return NULL when the slave device is being
un-slaved from a VRF. All other callers deal with this, but we lost
the fallback to loopback in ip6_rt_pcpu_alloc() -&gt; ip6_rt_get_dev_rcu()
with commit 4832c30d5458 ("net: ipv6: put host and anycast routes on
device with address").

  KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f]
  RIP: 0010:ip6_rt_pcpu_alloc (net/ipv6/route.c:1418)
  Call Trace:
   ip6_pol_route (net/ipv6/route.c:2318)
   fib6_rule_lookup (net/ipv6/fib6_rules.c:115)
   ip6_route_output_flags (net/ipv6/route.c:2607)
   vrf_process_v6_outbound (drivers/net/vrf.c:437)

I was tempted to rework the un-slaving code to clear the flag first
and insert synchronize_rcu() before we remove the upper. But looks like
the explicit fallback to loopback_dev is an established pattern.
And I guess avoiding the synchronize_rcu() is nice, too.

Fixes: 4832c30d5458 ("net: ipv6: put host and anycast routes on device with address")
Reviewed-by: David Ahern &lt;dsahern@kernel.org&gt;
Link: https://patch.msgid.link/20260301194548.927324-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>Convert 'alloc_obj' family to use the new default GFP_KERNEL argument</title>
<updated>2026-02-22T01:09:51+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-02-22T00:37:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43'/>
<id>urn:sha1:bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43</id>
<content type='text'>
This was done entirely with mindless brute force, using

    git grep -l '\&lt;k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>treewide: Replace kmalloc with kmalloc_obj for non-scalar types</title>
<updated>2026-02-21T09:02:28+00:00</updated>
<author>
<name>Kees Cook</name>
<email>kees@kernel.org</email>
</author>
<published>2026-02-21T07:49:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=69050f8d6d075dc01af7a5f2f550a8067510366f'/>
<id>urn:sha1:69050f8d6d075dc01af7a5f2f550a8067510366f</id>
<content type='text'>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook &lt;kees@kernel.org&gt;
</content>
</entry>
<entry>
<title>ipv6: use dst6_mtu() instead of dst_mtu()</title>
<updated>2026-02-03T01:49:29+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2026-01-30T21:03:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=b40f0130a23b6bab8b359e158a40af81f11f14be'/>
<id>urn:sha1:b40f0130a23b6bab8b359e158a40af81f11f14be</id>
<content type='text'>
When we expect an IPv6 dst, use dst6_mtu() instead of dst_mtu()
to save some code space.

Due to current dst6_mtu() implementation, only convert
users in IPv6 stack.

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reviewed-by: Kuniyuki Iwashima &lt;kuniyu@google.com&gt;
Link: https://patch.msgid.link/20260130210303.3888261-7-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>ipv6: annotate data-races in net/ipv6/route.c</title>
<updated>2026-01-19T17:56:43+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2026-01-15T09:41:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=f062e8e25102324364aada61b8283356235bc3c1'/>
<id>urn:sha1:f062e8e25102324364aada61b8283356235bc3c1</id>
<content type='text'>
sysctls are read while their values can change,
add READ_ONCE() annotations.

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Link: https://patch.msgid.link/20260115094141.3124990-9-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net</title>
<updated>2026-01-16T02:02:48+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2026-01-08T19:37:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=c27022497dd9b8a8922dbb878c255e4260a90e6c'/>
<id>urn:sha1:c27022497dd9b8a8922dbb878c255e4260a90e6c</id>
<content type='text'>
Cross-merge networking fixes after downstream PR (net-6.19-rc6).

No conflicts, or adjacent changes.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>dst: fix races in rt6_uncached_list_del() and rt_del_uncached_list()</title>
<updated>2026-01-14T03:08:18+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2026-01-12T10:38:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=9a6f0c4d5796ab89b5a28a890ce542344d58bd69'/>
<id>urn:sha1:9a6f0c4d5796ab89b5a28a890ce542344d58bd69</id>
<content type='text'>
syzbot was able to crash the kernel in rt6_uncached_list_flush_dev()
in an interesting way [1]

Crash happens in list_del_init()/INIT_LIST_HEAD() while writing
list-&gt;prev, while the prior write on list-&gt;next went well.

static inline void INIT_LIST_HEAD(struct list_head *list)
{
	WRITE_ONCE(list-&gt;next, list); // This went well
	WRITE_ONCE(list-&gt;prev, list); // Crash, @list has been freed.
}

Issue here is that rt6_uncached_list_del() did not attempt to lock
ul-&gt;lock, as list_empty(&amp;rt-&gt;dst.rt_uncached) returned
true because the WRITE_ONCE(list-&gt;next, list) happened on the other CPU.

We might use list_del_init_careful() and list_empty_careful(),
or make sure rt6_uncached_list_del() always grabs the spinlock
whenever rt-&gt;dst.rt_uncached_list has been set.

A similar fix is neeed for IPv4.

[1]

 BUG: KASAN: slab-use-after-free in INIT_LIST_HEAD include/linux/list.h:46 [inline]
 BUG: KASAN: slab-use-after-free in list_del_init include/linux/list.h:296 [inline]
 BUG: KASAN: slab-use-after-free in rt6_uncached_list_flush_dev net/ipv6/route.c:191 [inline]
 BUG: KASAN: slab-use-after-free in rt6_disable_ip+0x633/0x730 net/ipv6/route.c:5020
Write of size 8 at addr ffff8880294cfa78 by task kworker/u8:14/3450

CPU: 0 UID: 0 PID: 3450 Comm: kworker/u8:14 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: netns cleanup_net
Call Trace:
 &lt;TASK&gt;
  dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
  print_address_description mm/kasan/report.c:378 [inline]
  print_report+0xca/0x240 mm/kasan/report.c:482
  kasan_report+0x118/0x150 mm/kasan/report.c:595
  INIT_LIST_HEAD include/linux/list.h:46 [inline]
  list_del_init include/linux/list.h:296 [inline]
  rt6_uncached_list_flush_dev net/ipv6/route.c:191 [inline]
  rt6_disable_ip+0x633/0x730 net/ipv6/route.c:5020
  addrconf_ifdown+0x143/0x18a0 net/ipv6/addrconf.c:3853
 addrconf_notify+0x1bc/0x1050 net/ipv6/addrconf.c:-1
  notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
  call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
  call_netdevice_notifiers net/core/dev.c:2282 [inline]
  netif_close_many+0x29c/0x410 net/core/dev.c:1785
  unregister_netdevice_many_notify+0xb50/0x2330 net/core/dev.c:12353
  ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
  ops_undo_list+0x3dc/0x990 net/core/net_namespace.c:248
  cleanup_net+0x4de/0x7b0 net/core/net_namespace.c:696
  process_one_work kernel/workqueue.c:3257 [inline]
  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 &lt;/TASK&gt;

Allocated by task 803:
  kasan_save_stack mm/kasan/common.c:57 [inline]
  kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
  unpoison_slab_object mm/kasan/common.c:340 [inline]
  __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
  kasan_slab_alloc include/linux/kasan.h:253 [inline]
  slab_post_alloc_hook mm/slub.c:4953 [inline]
  slab_alloc_node mm/slub.c:5263 [inline]
  kmem_cache_alloc_noprof+0x18d/0x6c0 mm/slub.c:5270
  dst_alloc+0x105/0x170 net/core/dst.c:89
  ip6_dst_alloc net/ipv6/route.c:342 [inline]
  icmp6_dst_alloc+0x75/0x460 net/ipv6/route.c:3333
  mld_sendpack+0x683/0xe60 net/ipv6/mcast.c:1844
  mld_send_cr net/ipv6/mcast.c:2154 [inline]
  mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
  process_one_work kernel/workqueue.c:3257 [inline]
  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Freed by task 20:
  kasan_save_stack mm/kasan/common.c:57 [inline]
  kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
  kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
  poison_slab_object mm/kasan/common.c:253 [inline]
  __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
  kasan_slab_free include/linux/kasan.h:235 [inline]
  slab_free_hook mm/slub.c:2540 [inline]
  slab_free mm/slub.c:6670 [inline]
  kmem_cache_free+0x18f/0x8d0 mm/slub.c:6781
  dst_destroy+0x235/0x350 net/core/dst.c:121
  rcu_do_batch kernel/rcu/tree.c:2605 [inline]
  rcu_core kernel/rcu/tree.c:2857 [inline]
  rcu_cpu_kthread+0xba5/0x1af0 kernel/rcu/tree.c:2945
  smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

Last potentially related work creation:
  kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
  kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
  __call_rcu_common kernel/rcu/tree.c:3119 [inline]
  call_rcu+0xee/0x890 kernel/rcu/tree.c:3239
  refdst_drop include/net/dst.h:266 [inline]
  skb_dst_drop include/net/dst.h:278 [inline]
  skb_release_head_state+0x71/0x360 net/core/skbuff.c:1156
  skb_release_all net/core/skbuff.c:1180 [inline]
  __kfree_skb net/core/skbuff.c:1196 [inline]
  sk_skb_reason_drop+0xe9/0x170 net/core/skbuff.c:1234
  kfree_skb_reason include/linux/skbuff.h:1322 [inline]
  tcf_kfree_skb_list include/net/sch_generic.h:1127 [inline]
  __dev_xmit_skb net/core/dev.c:4260 [inline]
  __dev_queue_xmit+0x26aa/0x3210 net/core/dev.c:4785
  NF_HOOK_COND include/linux/netfilter.h:307 [inline]
  ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
  NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318
  mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855
  mld_send_cr net/ipv6/mcast.c:2154 [inline]
  mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
  process_one_work kernel/workqueue.c:3257 [inline]
  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

The buggy address belongs to the object at ffff8880294cfa00
 which belongs to the cache ip6_dst_cache of size 232
The buggy address is located 120 bytes inside of
 freed 232-byte region [ffff8880294cfa00, ffff8880294cfae8)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x294cf
memcg:ffff88803536b781
flags: 0x80000000000000(node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000000 ffff88802ff1c8c0 ffffea0000bf2bc0 dead000000000006
raw: 0000000000000000 00000000800c000c 00000000f5000000 ffff88803536b781
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 9, tgid 9 (kworker/0:0), ts 91119585830, free_ts 91088628818
  set_page_owner include/linux/page_owner.h:32 [inline]
  post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857
  prep_new_page mm/page_alloc.c:1865 [inline]
  get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3915
  __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
  alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486
  alloc_slab_page mm/slub.c:3075 [inline]
  allocate_slab+0x86/0x3b0 mm/slub.c:3248
  new_slab mm/slub.c:3302 [inline]
  ___slab_alloc+0xb10/0x13e0 mm/slub.c:4656
  __slab_alloc+0xc6/0x1f0 mm/slub.c:4779
  __slab_alloc_node mm/slub.c:4855 [inline]
  slab_alloc_node mm/slub.c:5251 [inline]
  kmem_cache_alloc_noprof+0x101/0x6c0 mm/slub.c:5270
  dst_alloc+0x105/0x170 net/core/dst.c:89
  ip6_dst_alloc net/ipv6/route.c:342 [inline]
  icmp6_dst_alloc+0x75/0x460 net/ipv6/route.c:3333
  mld_sendpack+0x683/0xe60 net/ipv6/mcast.c:1844
  mld_send_cr net/ipv6/mcast.c:2154 [inline]
  mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
  process_one_work kernel/workqueue.c:3257 [inline]
  process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
page last free pid 5859 tgid 5859 stack trace:
  reset_page_owner include/linux/page_owner.h:25 [inline]
  free_pages_prepare mm/page_alloc.c:1406 [inline]
  __free_frozen_pages+0xfe1/0x1170 mm/page_alloc.c:2943
  discard_slab mm/slub.c:3346 [inline]
  __put_partials+0x149/0x170 mm/slub.c:3886
  __slab_free+0x2af/0x330 mm/slub.c:5952
  qlink_free mm/kasan/quarantine.c:163 [inline]
  qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
  kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
  __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
  kasan_slab_alloc include/linux/kasan.h:253 [inline]
  slab_post_alloc_hook mm/slub.c:4953 [inline]
  slab_alloc_node mm/slub.c:5263 [inline]
  kmem_cache_alloc_noprof+0x18d/0x6c0 mm/slub.c:5270
  getname_flags+0xb8/0x540 fs/namei.c:146
  getname include/linux/fs.h:2498 [inline]
  do_sys_openat2+0xbc/0x200 fs/open.c:1426
  do_sys_open fs/open.c:1436 [inline]
  __do_sys_openat fs/open.c:1452 [inline]
  __se_sys_openat fs/open.c:1447 [inline]
  __x64_sys_openat+0x138/0x170 fs/open.c:1447
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94

Fixes: 8d0b94afdca8 ("ipv6: Keep track of DST_NOCACHE routes in case of iface down/unregister")
Fixes: 78df76a065ae ("ipv4: take rt_uncached_lock only if needed")
Reported-by: syzbot+179fc225724092b8b2b2@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6964cdf2.050a0220.eaf7.009d.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Martin KaFai Lau &lt;martin.lau@kernel.org&gt;
Reviewed-by: David Ahern &lt;dsahern@kernel.org&gt;
Link: https://patch.msgid.link/20260112103825.3810713-1-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>ipv6: Allow for nexthop device mismatch with "onlink"</title>
<updated>2026-01-14T02:57:34+00:00</updated>
<author>
<name>Ido Schimmel</name>
<email>idosch@nvidia.com</email>
</author>
<published>2026-01-11T12:08:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=b853b94e848216b82ecaa0d5d3c7f6c9066e32a4'/>
<id>urn:sha1:b853b94e848216b82ecaa0d5d3c7f6c9066e32a4</id>
<content type='text'>
IPv4 allows for a nexthop device mismatch when the "onlink" keyword is
specified:

 # ip link add name dummy1 up type dummy
 # ip address add 192.0.2.1/24 dev dummy1
 # ip link add name dummy2 up type dummy
 # ip route add 198.51.100.0/24 nexthop via 192.0.2.2 dev dummy2
 Error: Nexthop has invalid gateway.
 # ip route add 198.51.100.0/24 nexthop via 192.0.2.2 dev dummy2 onlink
 # echo $?
 0

This seems to be consistent with the description of "onlink" in the
ip-route man page: "Pretend that the nexthop is directly attached to
this link, even if it does not match any interface prefix".

On the other hand, IPv6 rejects a nexthop device mismatch, even when
"onlink" is specified:

 # ip link add name dummy1 up type dummy
 # ip address add 2001:db8:1::1/64 dev dummy1
 # ip link add name dummy2 up type dummy
 # ip route add 2001:db8:10::/64 nexthop via 2001:db8:1::2 dev dummy2
 RTNETLINK answers: No route to host
 # ip route add 2001:db8:10::/64 nexthop via 2001:db8:1::2 dev dummy2 onlink
 Error: Nexthop has invalid gateway or device mismatch.

This is intentional according to commit fc1e64e1092f ("net/ipv6: Add
support for onlink flag") which added IPv6 "onlink" support and states
that "any unicast gateway is allowed as long as the gateway is not a
local address and if it resolves it must match the given device".

The condition was later relaxed in commit 4ed591c8ab44 ("net/ipv6: Allow
onlink routes to have a device mismatch if it is the default route") to
allow for a nexthop device mismatch if the gateway address is resolved
via the default route:

 # ip link add name dummy1 up type dummy
 # ip route add ::/0 dev dummy1
 # ip link add name dummy2 up type dummy
 # ip route add 2001:db8:10::/64 nexthop via 2001:db8:1::2 dev dummy2
 RTNETLINK answers: No route to host
 # ip route add 2001:db8:10::/64 nexthop via 2001:db8:1::2 dev dummy2 onlink
 # echo $?
 0

While the decision to forbid a nexthop device mismatch in IPv6 seems to
be intentional, it is unclear why it was made. Especially when it
differs from IPv4 and seems to go against the intended behavior of
"onlink".

Therefore, relax the condition further and allow for a nexthop device
mismatch when "onlink" is specified:

 # ip link add name dummy1 up type dummy
 # ip address add 2001:db8:1::1/64 dev dummy1
 # ip link add name dummy2 up type dummy
 # ip route add 2001:db8:10::/64 nexthop via 2001:db8:1::2 dev dummy2 onlink
 # echo $?
 0

The motivating use case is the fact that FRR would like to be able to
configure overlay routes of the following form:

 # ip route add &lt;host-Z&gt; vrf &lt;VRF&gt; encap ip id &lt;ID&gt; src &lt;VTEP-A&gt; dst &lt;VTEP-Z&gt; via &lt;VTEP-Z&gt; dev vxlan0 onlink

Where vxlan0 is in the default VRF in which "VTEP-Z" is reachable via
one of the underlay routes (e.g., via swpX). Without this patch, the
above only works with IPv4, but not with IPv6.

Reviewed-by: Petr Machata &lt;petrm@nvidia.com&gt;
Signed-off-by: Ido Schimmel &lt;idosch@nvidia.com&gt;
Reviewed-by: David Ahern &lt;dsahern@kernel.org&gt;
Link: https://patch.msgid.link/20260111120813.159799-5-idosch@nvidia.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
</feed>
