<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/net/core/dst.c, branch v6.6.132</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v6.6.132</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v6.6.132'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2026-03-25T10:05:58+00:00</updated>
<entry>
<title>dst: fix races in rt6_uncached_list_del() and rt_del_uncached_list()</title>
<updated>2026-03-25T10:05:58+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2026-02-24T05:49:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=815db2363e51f0ef416947492d4dac5b7a520f56'/>
<id>urn:sha1:815db2363e51f0ef416947492d4dac5b7a520f56</id>
<content type='text'>
[ Upstream commit 9a6f0c4d5796ab89b5a28a890ce542344d58bd69 ]

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;
Signed-off-by: Rahul Sharma &lt;black.hawk@163.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>net: dst: annotate data-races around dst-&gt;output</title>
<updated>2025-08-15T10:08:46+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2025-06-30T12:19:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=f73c0bc2d1d306092babcc2fe617fb9686cce74d'/>
<id>urn:sha1:f73c0bc2d1d306092babcc2fe617fb9686cce74d</id>
<content type='text'>
[ Upstream commit 2dce8c52a98995c4719def6f88629ab1581c0b82 ]

dst_dev_put() can overwrite dst-&gt;output while other
cpus might read this field (for instance from dst_output())

Add READ_ONCE()/WRITE_ONCE() annotations to suppress
potential issues.

We will likely need RCU protection in the future.

Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reviewed-by: Kuniyuki Iwashima &lt;kuniyu@google.com&gt;
Link: https://patch.msgid.link/20250630121934.3399505-6-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>net: dst: annotate data-races around dst-&gt;input</title>
<updated>2025-08-15T10:08:46+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2025-06-30T12:19:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=e0b8b6687b7d5c4428d9042b5963034e4bf9b995'/>
<id>urn:sha1:e0b8b6687b7d5c4428d9042b5963034e4bf9b995</id>
<content type='text'>
[ Upstream commit f1c5fd34891a1c242885f48c2e4dc52df180f311 ]

dst_dev_put() can overwrite dst-&gt;input while other
cpus might read this field (for instance from dst_input())

Add READ_ONCE()/WRITE_ONCE() annotations to suppress
potential issues.

We will likely need full RCU protection later.

Fixes: 4a6ce2b6f2ec ("net: introduce a new function dst_dev_put()")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reviewed-by: Kuniyuki Iwashima &lt;kuniyu@google.com&gt;
Link: https://patch.msgid.link/20250630121934.3399505-5-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>net: decrease cached dst counters in dst_release</title>
<updated>2025-04-10T12:37:40+00:00</updated>
<author>
<name>Antoine Tenart</name>
<email>atenart@kernel.org</email>
</author>
<published>2025-03-26T17:36:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=ccc331fd5bcae131d2627d5ef099d4a1f6540aea'/>
<id>urn:sha1:ccc331fd5bcae131d2627d5ef099d4a1f6540aea</id>
<content type='text'>
[ Upstream commit 3a0a3ff6593d670af2451ec363ccb7b18aec0c0a ]

Upstream fix ac888d58869b ("net: do not delay dst_entries_add() in
dst_release()") moved decrementing the dst count from dst_destroy to
dst_release to avoid accessing already freed data in case of netns
dismantle. However in case CONFIG_DST_CACHE is enabled and OvS+tunnels
are used, this fix is incomplete as the same issue will be seen for
cached dsts:

  Unable to handle kernel paging request at virtual address ffff5aabf6b5c000
  Call trace:
   percpu_counter_add_batch+0x3c/0x160 (P)
   dst_release+0xec/0x108
   dst_cache_destroy+0x68/0xd8
   dst_destroy+0x13c/0x168
   dst_destroy_rcu+0x1c/0xb0
   rcu_do_batch+0x18c/0x7d0
   rcu_core+0x174/0x378
   rcu_core_si+0x18/0x30

Fix this by invalidating the cache, and thus decrementing cached dst
counters, in dst_release too.

Fixes: d71785ffc7e7 ("net: add dst_cache to ovs vxlan lwtunnel")
Signed-off-by: Antoine Tenart &lt;atenart@kernel.org&gt;
Link: https://patch.msgid.link/20250326173634.31096-1-atenart@kernel.org
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>net: do not delay dst_entries_add() in dst_release()</title>
<updated>2024-10-17T13:24:28+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2024-10-08T14:31:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=eae7435b48ffc8e9be0ff9cfeae40af479a609dd'/>
<id>urn:sha1:eae7435b48ffc8e9be0ff9cfeae40af479a609dd</id>
<content type='text'>
[ Upstream commit ac888d58869bb99753e7652be19a151df9ecb35d ]

dst_entries_add() uses per-cpu data that might be freed at netns
dismantle from ip6_route_net_exit() calling dst_entries_destroy()

Before ip6_route_net_exit() can be called, we release all
the dsts associated with this netns, via calls to dst_release(),
which waits an rcu grace period before calling dst_destroy()

dst_entries_add() use in dst_destroy() is racy, because
dst_entries_destroy() could have been called already.

Decrementing the number of dsts must happen sooner.

Notes:

1) in CONFIG_XFRM case, dst_destroy() can call
   dst_release_immediate(child), this might also cause UAF
   if the child does not have DST_NOCOUNT set.
   IPSEC maintainers might take a look and see how to address this.

2) There is also discussion about removing this count of dst,
   which might happen in future kernels.

Fixes: f88649721268 ("ipv4: fix dst race in sk_dst_get()")
Closes: https://lore.kernel.org/lkml/CANn89iLCCGsP7SFn9HKpvnKu96Td4KD08xf7aGtiYgZnkjaL=w@mail.gmail.com/T/
Reported-by: Naresh Kamboju &lt;naresh.kamboju@linaro.org&gt;
Tested-by: Linux Kernel Functional Testing &lt;lkft@linaro.org&gt;
Tested-by: Naresh Kamboju &lt;naresh.kamboju@linaro.org&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Xin Long &lt;lucien.xin@gmail.com&gt;
Cc: Steffen Klassert &lt;steffen.klassert@secunet.com&gt;
Reviewed-by: Xin Long &lt;lucien.xin@gmail.com&gt;
Link: https://patch.msgid.link/20241008143110.1064899-1-edumazet@google.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>net: remove unnecessary input parameter 'how' in ifdown function</title>
<updated>2023-08-22T11:19:02+00:00</updated>
<author>
<name>Zhengchao Shao</name>
<email>shaozhengchao@huawei.com</email>
</author>
<published>2023-08-21T08:41:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=43c2817225fce05701f062a996255007481935e2'/>
<id>urn:sha1:43c2817225fce05701f062a996255007481935e2</id>
<content type='text'>
When the ifdown function in the dst_ops structure is referenced, the input
parameter 'how' is always true. In the current implementation of the
ifdown interface, ip6_dst_ifdown does not use the input parameter 'how',
xfrm6_dst_ifdown and xfrm4_dst_ifdown functions use the input parameter
'unregister'. But false judgment on 'unregister' in xfrm6_dst_ifdown and
xfrm4_dst_ifdown is false, so remove the input parameter 'how' in ifdown
function.

Signed-off-by: Zhengchao Shao &lt;shaozhengchao@huawei.com&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Link: https://lore.kernel.org/r/20230821084104.3812233-1-shaozhengchao@huawei.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
</content>
</entry>
<entry>
<title>net: dst: fix missing initialization of rt_uncached</title>
<updated>2023-04-22T03:26:56+00:00</updated>
<author>
<name>Maxime Bizon</name>
<email>mbizon@freebox.fr</email>
</author>
<published>2023-04-20T18:25:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=418a73074da9182f571e467eaded03ea501f3281'/>
<id>urn:sha1:418a73074da9182f571e467eaded03ea501f3281</id>
<content type='text'>
xfrm_alloc_dst() followed by xfrm4_dst_destroy(), without a
xfrm4_fill_dst() call in between, causes the following BUG:

 BUG: spinlock bad magic on CPU#0, fbxhostapd/732
  lock: 0x890b7668, .magic: 890b7668, .owner: &lt;none&gt;/-1, .owner_cpu: 0
 CPU: 0 PID: 732 Comm: fbxhostapd Not tainted 6.3.0-rc6-next-20230414-00613-ge8de66369925-dirty #9
 Hardware name: Marvell Kirkwood (Flattened Device Tree)
  unwind_backtrace from show_stack+0x10/0x14
  show_stack from dump_stack_lvl+0x28/0x30
  dump_stack_lvl from do_raw_spin_lock+0x20/0x80
  do_raw_spin_lock from rt_del_uncached_list+0x30/0x64
  rt_del_uncached_list from xfrm4_dst_destroy+0x3c/0xbc
  xfrm4_dst_destroy from dst_destroy+0x5c/0xb0
  dst_destroy from rcu_process_callbacks+0xc4/0xec
  rcu_process_callbacks from __do_softirq+0xb4/0x22c
  __do_softirq from call_with_stack+0x1c/0x24
  call_with_stack from do_softirq+0x60/0x6c
  do_softirq from __local_bh_enable_ip+0xa0/0xcc

Patch "net: dst: Prevent false sharing vs. dst_entry:: __refcnt" moved
rt_uncached and rt_uncached_list fields from rtable struct to dst
struct, so they are more zeroed by memset_after(xdst, 0, u.dst) in
xfrm_alloc_dst().

Note that rt_uncached (list_head) was never properly initialized at
alloc time, but xfrm[46]_dst_destroy() is written in such a way that
it was not an issue thanks to the memset:

	if (xdst-&gt;u.rt.dst.rt_uncached_list)
		rt_del_uncached_list(&amp;xdst-&gt;u.rt);

The route code does it the other way around: rt_uncached_list is
assumed to be valid IIF rt_uncached list_head is not empty:

void rt_del_uncached_list(struct rtable *rt)
{
        if (!list_empty(&amp;rt-&gt;dst.rt_uncached)) {
                struct uncached_list *ul = rt-&gt;dst.rt_uncached_list;

                spin_lock_bh(&amp;ul-&gt;lock);
                list_del_init(&amp;rt-&gt;dst.rt_uncached);
                spin_unlock_bh(&amp;ul-&gt;lock);
        }
}

This patch adds mandatory rt_uncached list_head initialization in
generic dst_init(), and adapt xfrm[46]_dst_destroy logic to match the
rest of the code.

Fixes: d288a162dd1c ("net: dst: Prevent false sharing vs. dst_entry:: __refcnt")
Reported-by: kernel test robot &lt;oliver.sang@intel.com&gt;
Link: https://lore.kernel.org/oe-lkp/202304162125.18b7bcdd-oliver.sang@intel.com
Reviewed-by: David Ahern &lt;dsahern@kernel.org&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
CC: Leon Romanovsky &lt;leon@kernel.org&gt;
Signed-off-by: Maxime Bizon &lt;mbizon@freebox.fr&gt;
Link: https://lore.kernel.org/r/20230420182508.2417582-1-mbizon@freebox.fr
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>net: dst: Switch to rcuref_t reference counting</title>
<updated>2023-03-29T01:52:28+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2023-03-23T20:55:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=bc9d3a9f2afca189a6ae40225b6985e3c775375e'/>
<id>urn:sha1:bc9d3a9f2afca189a6ae40225b6985e3c775375e</id>
<content type='text'>
Under high contention dst_entry::__refcnt becomes a significant bottleneck.

atomic_inc_not_zero() is implemented with a cmpxchg() loop, which goes into
high retry rates on contention.

Switch the reference count to rcuref_t which results in a significant
performance gain. Rename the reference count member to __rcuref to reflect
the change.

The gain depends on the micro-architecture and the number of concurrent
operations and has been measured in the range of +25% to +130% with a
localhost memtier/memcached benchmark which amplifies the problem
massively.

Running the memtier/memcached benchmark over a real (1Gb) network
connection the conversion on top of the false sharing fix for struct
dst_entry::__refcnt results in a total gain in the 2%-5% range over the
upstream baseline.

Reported-by: Wangyang Guo &lt;wangyang.guo@intel.com&gt;
Reported-by: Arjan Van De Ven &lt;arjan.van.de.ven@intel.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/r/20230307125538.989175656@linutronix.de
Link: https://lore.kernel.org/r/20230323102800.215027837@linutronix.de
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>ipv6: remove max_size check inline with ipv4</title>
<updated>2023-01-14T04:59:14+00:00</updated>
<author>
<name>Jon Maxwell</name>
<email>jmaxwell37@gmail.com</email>
</author>
<published>2023-01-12T01:25:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=af6d10345ca76670c1b7c37799f0d5576ccef277'/>
<id>urn:sha1:af6d10345ca76670c1b7c37799f0d5576ccef277</id>
<content type='text'>
In ip6_dst_gc() replace:

  if (entries &gt; gc_thresh)

With:

  if (entries &gt; ops-&gt;gc_thresh)

Sending Ipv6 packets in a loop via a raw socket triggers an issue where a
route is cloned by ip6_rt_cache_alloc() for each packet sent. This quickly
consumes the Ipv6 max_size threshold which defaults to 4096 resulting in
these warnings:

[1]   99.187805] dst_alloc: 7728 callbacks suppressed
[2] Route cache is full: consider increasing sysctl net.ipv6.route.max_size.
.
.
[300] Route cache is full: consider increasing sysctl net.ipv6.route.max_size.

When this happens the packet is dropped and sendto() gets a network is
unreachable error:

remaining pkt 200557 errno 101
remaining pkt 196462 errno 101
.
.
remaining pkt 126821 errno 101

Implement David Aherns suggestion to remove max_size check seeing that Ipv6
has a GC to manage memory usage. Ipv4 already does not check max_size.

Here are some memory comparisons for Ipv4 vs Ipv6 with the patch:

Test by running 5 instances of a program that sends UDP packets to a raw
socket 5000000 times. Compare Ipv4 and Ipv6 performance with a similar
program.

Ipv4:

Before test:

MemFree:        29427108 kB
Slab:             237612 kB

ip6_dst_cache       1912   2528    256   32    2 : tunables    0    0    0
xfrm_dst_cache         0      0    320   25    2 : tunables    0    0    0
ip_dst_cache        2881   3990    192   42    2 : tunables    0    0    0

During test:

MemFree:        29417608 kB
Slab:             247712 kB

ip6_dst_cache       1912   2528    256   32    2 : tunables    0    0    0
xfrm_dst_cache         0      0    320   25    2 : tunables    0    0    0
ip_dst_cache       44394  44394    192   42    2 : tunables    0    0    0

After test:

MemFree:        29422308 kB
Slab:             238104 kB

ip6_dst_cache       1912   2528    256   32    2 : tunables    0    0    0
xfrm_dst_cache         0      0    320   25    2 : tunables    0    0    0
ip_dst_cache        3048   4116    192   42    2 : tunables    0    0    0

Ipv6 with patch:

Errno 101 errors are not observed anymore with the patch.

Before test:

MemFree:        29422308 kB
Slab:             238104 kB

ip6_dst_cache       1912   2528    256   32    2 : tunables    0    0    0
xfrm_dst_cache         0      0    320   25    2 : tunables    0    0    0
ip_dst_cache        3048   4116    192   42    2 : tunables    0    0    0

During Test:

MemFree:        29431516 kB
Slab:             240940 kB

ip6_dst_cache      11980  12064    256   32    2 : tunables    0    0    0
xfrm_dst_cache         0      0    320   25    2 : tunables    0    0    0
ip_dst_cache        3048   4116    192   42    2 : tunables    0    0    0

After Test:

MemFree:        29441816 kB
Slab:             238132 kB

ip6_dst_cache       1902   2432    256   32    2 : tunables    0    0    0
xfrm_dst_cache         0      0    320   25    2 : tunables    0    0    0
ip_dst_cache        3048   4116    192   42    2 : tunables    0    0    0

Tested-by: Andrea Mayer &lt;andrea.mayer@uniroma2.it&gt;
Signed-off-by: Jon Maxwell &lt;jmaxwell37@gmail.com&gt;
Reviewed-by: David Ahern &lt;dsahern@kernel.org&gt;
Link: https://lore.kernel.org/r/20230112012532.311021-1-jmaxwell37@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>Merge tag 'net-next-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next</title>
<updated>2022-12-13T23:47:48+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-12-13T23:47:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=7e68dd7d07a28faa2e6574dd6b9dbd90cdeaae91'/>
<id>urn:sha1:7e68dd7d07a28faa2e6574dd6b9dbd90cdeaae91</id>
<content type='text'>
Pull networking updates from Paolo Abeni:
 "Core:

   - Allow live renaming when an interface is up

   - Add retpoline wrappers for tc, improving considerably the
     performances of complex queue discipline configurations

   - Add inet drop monitor support

   - A few GRO performance improvements

   - Add infrastructure for atomic dev stats, addressing long standing
     data races

   - De-duplicate common code between OVS and conntrack offloading
     infrastructure

   - A bunch of UBSAN_BOUNDS/FORTIFY_SOURCE improvements

   - Netfilter: introduce packet parser for tunneled packets

   - Replace IPVS timer-based estimators with kthreads to scale up the
     workload with the number of available CPUs

   - Add the helper support for connection-tracking OVS offload

  BPF:

   - Support for user defined BPF objects: the use case is to allocate
     own objects, build own object hierarchies and use the building
     blocks to build own data structures flexibly, for example, linked
     lists in BPF

   - Make cgroup local storage available to non-cgroup attached BPF
     programs

   - Avoid unnecessary deadlock detection and failures wrt BPF task
     storage helpers

   - A relevant bunch of BPF verifier fixes and improvements

   - Veristat tool improvements to support custom filtering, sorting,
     and replay of results

   - Add LLVM disassembler as default library for dumping JITed code

   - Lots of new BPF documentation for various BPF maps

   - Add bpf_rcu_read_{,un}lock() support for sleepable programs

   - Add RCU grace period chaining to BPF to wait for the completion of
     access from both sleepable and non-sleepable BPF programs

   - Add support storing struct task_struct objects as kptrs in maps

   - Improve helper UAPI by explicitly defining BPF_FUNC_xxx integer
     values

   - Add libbpf *_opts API-variants for bpf_*_get_fd_by_id() functions

  Protocols:

   - TCP: implement Protective Load Balancing across switch links

   - TCP: allow dynamically disabling TCP-MD5 static key, reverting back
     to fast[er]-path

   - UDP: Introduce optional per-netns hash lookup table

   - IPv6: simplify and cleanup sockets disposal

   - Netlink: support different type policies for each generic netlink
     operation

   - MPTCP: add MSG_FASTOPEN and FastOpen listener side support

   - MPTCP: add netlink notification support for listener sockets events

   - SCTP: add VRF support, allowing sctp sockets binding to VRF devices

   - Add bridging MAC Authentication Bypass (MAB) support

   - Extensions for Ethernet VPN bridging implementation to better
     support multicast scenarios

   - More work for Wi-Fi 7 support, comprising conversion of all the
     existing drivers to internal TX queue usage

   - IPSec: introduce a new offload type (packet offload) allowing
     complete header processing and crypto offloading

   - IPSec: extended ack support for more descriptive XFRM error
     reporting

   - RXRPC: increase SACK table size and move processing into a
     per-local endpoint kernel thread, reducing considerably the
     required locking

   - IEEE 802154: synchronous send frame and extended filtering support,
     initial support for scanning available 15.4 networks

   - Tun: bump the link speed from 10Mbps to 10Gbps

   - Tun/VirtioNet: implement UDP segmentation offload support

  Driver API:

   - PHY/SFP: improve power level switching between standard level 1 and
     the higher power levels

   - New API for netdev &lt;-&gt; devlink_port linkage

   - PTP: convert existing drivers to new frequency adjustment
     implementation

   - DSA: add support for rx offloading

   - Autoload DSA tagging driver when dynamically changing protocol

   - Add new PCP and APPTRUST attributes to Data Center Bridging

   - Add configuration support for 800Gbps link speed

   - Add devlink port function attribute to enable/disable RoCE and
     migratable

   - Extend devlink-rate to support strict prioriry and weighted fair
     queuing

   - Add devlink support to directly reading from region memory

   - New device tree helper to fetch MAC address from nvmem

   - New big TCP helper to simplify temporary header stripping

  New hardware / drivers:

   - Ethernet:
      - Marvel Octeon CNF95N and CN10KB Ethernet Switches
      - Marvel Prestera AC5X Ethernet Switch
      - WangXun 10 Gigabit NIC
      - Motorcomm yt8521 Gigabit Ethernet
      - Microchip ksz9563 Gigabit Ethernet Switch
      - Microsoft Azure Network Adapter
      - Linux Automation 10Base-T1L adapter

   - PHY:
      - Aquantia AQR112 and AQR412
      - Motorcomm YT8531S

   - PTP:
      - Orolia ART-CARD

   - WiFi:
      - MediaTek Wi-Fi 7 (802.11be) devices
      - RealTek rtw8821cu, rtw8822bu, rtw8822cu and rtw8723du USB
        devices

   - Bluetooth:
      - Broadcom BCM4377/4378/4387 Bluetooth chipsets
      - Realtek RTL8852BE and RTL8723DS
      - Cypress.CYW4373A0 WiFi + Bluetooth combo device

  Drivers:

   - CAN:
      - gs_usb: bus error reporting support
      - kvaser_usb: listen only and bus error reporting support

   - Ethernet NICs:
      - Intel (100G):
         - extend action skbedit to RX queue mapping
         - implement devlink-rate support
         - support direct read from memory
      - nVidia/Mellanox (mlx5):
         - SW steering improvements, increasing rules update rate
         - Support for enhanced events compression
         - extend H/W offload packet manipulation capabilities
         - implement IPSec packet offload mode
      - nVidia/Mellanox (mlx4):
         - better big TCP support
      - Netronome Ethernet NICs (nfp):
         - IPsec offload support
         - add support for multicast filter
      - Broadcom:
         - RSS and PTP support improvements
      - AMD/SolarFlare:
         - netlink extened ack improvements
         - add basic flower matches to offload, and related stats
      - Virtual NICs:
         - ibmvnic: introduce affinity hint support
      - small / embedded:
         - FreeScale fec: add initial XDP support
         - Marvel mv643xx_eth: support MII/GMII/RGMII modes for Kirkwood
         - TI am65-cpsw: add suspend/resume support
         - Mediatek MT7986: add RX wireless wthernet dispatch support
         - Realtek 8169: enable GRO software interrupt coalescing per
           default

   - Ethernet high-speed switches:
      - Microchip (sparx5):
         - add support for Sparx5 TC/flower H/W offload via VCAP
      - Mellanox mlxsw:
         - add 802.1X and MAC Authentication Bypass offload support
         - add ip6gre support

   - Embedded Ethernet switches:
      - Mediatek (mtk_eth_soc):
         - improve PCS implementation, add DSA untag support
         - enable flow offload support
      - Renesas:
         - add rswitch R-Car Gen4 gPTP support
      - Microchip (lan966x):
         - add full XDP support
         - add TC H/W offload via VCAP
         - enable PTP on bridge interfaces
      - Microchip (ksz8):
         - add MTU support for KSZ8 series

   - Qualcomm 802.11ax WiFi (ath11k):
      - support configuring channel dwell time during scan

   - MediaTek WiFi (mt76):
      - enable Wireless Ethernet Dispatch (WED) offload support
      - add ack signal support
      - enable coredump support
      - remain_on_channel support

   - Intel WiFi (iwlwifi):
      - enable Wi-Fi 7 Extremely High Throughput (EHT) PHY capabilities
      - 320 MHz channels support

   - RealTek WiFi (rtw89):
      - new dynamic header firmware format support
      - wake-over-WLAN support"

* tag 'net-next-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2002 commits)
  ipvs: fix type warning in do_div() on 32 bit
  net: lan966x: Remove a useless test in lan966x_ptp_add_trap()
  net: ipa: add IPA v4.7 support
  dt-bindings: net: qcom,ipa: Add SM6350 compatible
  bnxt: Use generic HBH removal helper in tx path
  IPv6/GRO: generic helper to remove temporary HBH/jumbo header in driver
  selftests: forwarding: Add bridge MDB test
  selftests: forwarding: Rename bridge_mdb test
  bridge: mcast: Support replacement of MDB port group entries
  bridge: mcast: Allow user space to specify MDB entry routing protocol
  bridge: mcast: Allow user space to add (*, G) with a source list and filter mode
  bridge: mcast: Add support for (*, G) with a source list and filter mode
  bridge: mcast: Avoid arming group timer when (S, G) corresponds to a source
  bridge: mcast: Add a flag for user installed source entries
  bridge: mcast: Expose __br_multicast_del_group_src()
  bridge: mcast: Expose br_multicast_new_group_src()
  bridge: mcast: Add a centralized error path
  bridge: mcast: Place netlink policy before validation functions
  bridge: mcast: Split (*, G) and (S, G) addition into different functions
  bridge: mcast: Do not derive entry type from its filter mode
  ...
</content>
</entry>
</feed>
