55 Commits
Author SHA1 Message Date
Eric DumazetandJakub Kicinski 47e8dbb6e7 net/sched: do not reset queues in graft operations
Following typical script is extremely disruptive,
because each graft operation calls dev_deactivate()
which resets all the queues of the device.

QPARAM="limit 100000 flow_limit 1000 buckets 4096"
TXQS=64
for ETH in eth1
do
 tc qd del dev $ETH root 2>/dev/null
 tc qd add dev $ETH root handle 1: mq
 for i in `seq 1 $TXQS`
 do
   slot=$( printf %x $(( i )) )
   tc qd add dev $ETH parent 1:$slot fq $QPARAM
 done
done

One can add "ip link set dev $ETH down/up" to reduce the disruption time:

QPARAM="limit 100000 flow_limit 1000 buckets 4096"
TXQS=64
for ETH in eth1
do
 ip link set dev $ETH down
 tc qd del dev $ETH root 2>/dev/null
 tc qd add dev $ETH root handle 1: mq
 for i in `seq 1 $TXQS`
 do
   slot=$( printf %x $(( i )) )
   tc qd add dev $ETH parent 1:$slot fq $QPARAM
 done
 ip link set dev $ETH up
done

Or we can add a @reset_needed flag to dev_deactivate() and
dev_deactivate_many().

This flag is set to true at device dismantle or linkwatch_do_dev(),
and to false for graft operations.

In the future, we might only stop one queue instead of the whole
device, ie call dev_deactivate_queue() instead of dev_deactivate().

I think the problem (quadratic behavior) was added in commit
2fb541c862 ("net: sch_generic: aviod concurrent reset and enqueue op
for lockless qdisc") but this does not look serious enough to deserve
risky backports.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yunsheng Lin <linyunsheng@huawei.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Reviewed-by: Victor Nogueira <victor@mojatatu.com>
Link: https://patch.msgid.link/20260307163430.470644-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-03-09 18:55:55 -07:00
Jiayuan ChenandJakub Kicinski 83b67cc9be linkwatch: use __dev_put() in callers to prevent UAF
After linkwatch_do_dev() calls __dev_put() to release the linkwatch
reference, the device refcount may drop to 1. At this point,
netdev_run_todo() can proceed (since linkwatch_sync_dev() sees an
empty list and returns without blocking), wait for the refcount to
become 1 via netdev_wait_allrefs_any(), and then free the device
via kobject_put().

This creates a use-after-free when __linkwatch_run_queue() tries to
call netdev_unlock_ops() on the already-freed device.

Note that adding netdev_lock_ops()/netdev_unlock_ops() pair in
netdev_run_todo() before kobject_put() would not work, because
netdev_lock_ops() is conditional - it only locks when
netdev_need_ops_lock() returns true. If the device doesn't require
ops_lock, linkwatch won't hold any lock, and netdev_run_todo()
acquiring the lock won't provide synchronization.

Fix this by moving __dev_put() from linkwatch_do_dev() to its
callers. The device reference logically pairs with de-listing the
device, so it's reasonable for the caller that did the de-listing
to release it. This allows placing __dev_put() after all device
accesses are complete, preventing UAF.

The bug can be reproduced by adding mdelay(2000) after
linkwatch_do_dev() in __linkwatch_run_queue(), then running:

  ip tuntap add mode tun name tun_test
  ip link set tun_test up
  ip link set tun_test carrier off
  ip link set tun_test carrier on
  sleep 0.5
  ip tuntap del mode tun name tun_test

KASAN report:

 ==================================================================
 BUG: KASAN: use-after-free in netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]
 BUG: KASAN: use-after-free in netdev_unlock_ops include/net/netdev_lock.h:47 [inline]
 BUG: KASAN: use-after-free in __linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245
 Read of size 8 at addr ffff88804de5c008 by task kworker/u32:10/8123

 CPU: 0 UID: 0 PID: 8123 Comm: kworker/u32:10 Not tainted syzkaller #0 PREEMPT(full)
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
 Workqueue: events_unbound linkwatch_event
 Call Trace:
  <TASK>
  __dump_stack lib/dump_stack.c:94 [inline]
  dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
  print_address_description mm/kasan/report.c:378 [inline]
  print_report+0x156/0x4c9 mm/kasan/report.c:482
  kasan_report+0xdf/0x1a0 mm/kasan/report.c:595
  netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]
  netdev_unlock_ops include/net/netdev_lock.h:47 [inline]
  __linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245
  linkwatch_event+0x8f/0xc0 net/core/link_watch.c:304
  process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257
  process_scheduled_works kernel/workqueue.c:3340 [inline]
  worker_thread+0x5da/0xe40 kernel/workqueue.c:3421
  kthread+0x3b3/0x730 kernel/kthread.c:463
  ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
  </TASK>
 ==================================================================

Fixes: 04efcee6ef ("net: hold instance lock during NETDEV_CHANGE")
Reported-by: syzbot+1ec2f6a450f0b54af8c8@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/6824d064.a70a0220.3e9d8.001a.GAE@google.com/T/
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260201135915.393451-1-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-02 16:59:18 -08:00
Marco CrivellariandJakub Kicinski 9870d350e4 net: replace use of system_unbound_wq with system_dfl_wq
Currently if a user enqueue a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.

This lack of consistentcy cannot be addressed without refactoring the API.

system_unbound_wq should be the default workqueue so as not to enforce
locality constraints for random work whenever it's not required.

Adding system_dfl_wq to encourage its use when unbound work should be used.

The old system_unbound_wq will be kept for a few release cycles.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Link: https://patch.msgid.link/20250918142427.309519-2-marco.crivellari@suse.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-09-22 17:40:30 -07:00
Stanislav FomichevandJakub Kicinski 04efcee6ef net: hold instance lock during NETDEV_CHANGE
Cosmin reports an issue with ipv6_add_dev being called from
NETDEV_CHANGE notifier:

[ 3455.008776]  ? ipv6_add_dev+0x370/0x620
[ 3455.010097]  ipv6_find_idev+0x96/0xe0
[ 3455.010725]  addrconf_add_dev+0x1e/0xa0
[ 3455.011382]  addrconf_init_auto_addrs+0xb0/0x720
[ 3455.013537]  addrconf_notify+0x35f/0x8d0
[ 3455.014214]  notifier_call_chain+0x38/0xf0
[ 3455.014903]  netdev_state_change+0x65/0x90
[ 3455.015586]  linkwatch_do_dev+0x5a/0x70
[ 3455.016238]  rtnl_getlink+0x241/0x3e0
[ 3455.019046]  rtnetlink_rcv_msg+0x177/0x5e0

Similarly, linkwatch might get to ipv6_add_dev without ops lock:
[ 3456.656261]  ? ipv6_add_dev+0x370/0x620
[ 3456.660039]  ipv6_find_idev+0x96/0xe0
[ 3456.660445]  addrconf_add_dev+0x1e/0xa0
[ 3456.660861]  addrconf_init_auto_addrs+0xb0/0x720
[ 3456.661803]  addrconf_notify+0x35f/0x8d0
[ 3456.662236]  notifier_call_chain+0x38/0xf0
[ 3456.662676]  netdev_state_change+0x65/0x90
[ 3456.663112]  linkwatch_do_dev+0x5a/0x70
[ 3456.663529]  __linkwatch_run_queue+0xeb/0x200
[ 3456.663990]  linkwatch_event+0x21/0x30
[ 3456.664399]  process_one_work+0x211/0x610
[ 3456.664828]  worker_thread+0x1cc/0x380
[ 3456.665691]  kthread+0xf4/0x210

Reclassify NETDEV_CHANGE as a notifier that consistently runs under the
instance lock.

Link: https://lore.kernel.org/netdev/aac073de8beec3e531c86c101b274d434741c28e.camel@nvidia.com/
Reported-by: Cosmin Ratiu <cratiu@nvidia.com>
Tested-by: Cosmin Ratiu <cratiu@nvidia.com>
Fixes: ad7c7b2172 ("net: hold netdev instance lock during sysfs operations")
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250404161122.3907628-1-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-07 11:13:39 -07:00
Kuniyuki IwashimaandJakub Kicinski cb358ff941 ipvlan: Fix use-after-free in ipvlan_get_iflink().
syzbot presented an use-after-free report [0] regarding ipvlan and
linkwatch.

ipvlan does not hold a refcnt of the lower device unlike vlan and
macvlan.

If the linkwatch work is triggered for the ipvlan dev, the lower dev
might have already been freed, resulting in UAF of ipvlan->phy_dev in
ipvlan_get_iflink().

We can delay the lower dev unregistration like vlan and macvlan by
holding the lower dev's refcnt in dev->netdev_ops->ndo_init() and
releasing it in dev->priv_destructor().

Jakub pointed out calling .ndo_XXX after unregister_netdevice() has
returned is error prone and suggested [1] addressing this UAF in the
core by taking commit 750e516033 ("net: avoid potential UAF in
default_operstate()") further.

Let's assume unregistering devices DOWN and use RCU protection in
default_operstate() not to race with the device unregistration.

[0]:
BUG: KASAN: slab-use-after-free in ipvlan_get_iflink+0x84/0x88 drivers/net/ipvlan/ipvlan_main.c:353
Read of size 4 at addr ffff0000d768c0e0 by task kworker/u8:35/6944

CPU: 0 UID: 0 PID: 6944 Comm: kworker/u8:35 Not tainted 6.13.0-rc2-g9bc5c9515b48 #12 4c3cb9e8b4565456f6a355f312ff91f4f29b3c47
Hardware name: linux,dummy-virt (DT)
Workqueue: events_unbound linkwatch_event
Call trace:
 show_stack+0x38/0x50 arch/arm64/kernel/stacktrace.c:484 (C)
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xbc/0x108 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x16c/0x6f0 mm/kasan/report.c:489
 kasan_report+0xc0/0x120 mm/kasan/report.c:602
 __asan_report_load4_noabort+0x20/0x30 mm/kasan/report_generic.c:380
 ipvlan_get_iflink+0x84/0x88 drivers/net/ipvlan/ipvlan_main.c:353
 dev_get_iflink+0x7c/0xd8 net/core/dev.c:674
 default_operstate net/core/link_watch.c:45 [inline]
 rfc2863_policy+0x144/0x360 net/core/link_watch.c:72
 linkwatch_do_dev+0x60/0x228 net/core/link_watch.c:175
 __linkwatch_run_queue+0x2f4/0x5b8 net/core/link_watch.c:239
 linkwatch_event+0x64/0xa8 net/core/link_watch.c:282
 process_one_work+0x700/0x1398 kernel/workqueue.c:3229
 process_scheduled_works kernel/workqueue.c:3310 [inline]
 worker_thread+0x8c4/0xe10 kernel/workqueue.c:3391
 kthread+0x2b0/0x360 kernel/kthread.c:389
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862

Allocated by task 9303:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x30/0x68 mm/kasan/common.c:68
 kasan_save_alloc_info+0x44/0x58 mm/kasan/generic.c:568
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x84/0xa0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4283 [inline]
 __kmalloc_node_noprof+0x2a0/0x560 mm/slub.c:4289
 __kvmalloc_node_noprof+0x9c/0x230 mm/util.c:650
 alloc_netdev_mqs+0xb4/0x1118 net/core/dev.c:11209
 rtnl_create_link+0x2b8/0xb60 net/core/rtnetlink.c:3595
 rtnl_newlink_create+0x19c/0x868 net/core/rtnetlink.c:3771
 __rtnl_newlink net/core/rtnetlink.c:3896 [inline]
 rtnl_newlink+0x122c/0x15c0 net/core/rtnetlink.c:4011
 rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6901
 netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2542
 rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6928
 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
 netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1347
 netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg net/socket.c:726 [inline]
 __sys_sendto+0x2ec/0x438 net/socket.c:2197
 __do_sys_sendto net/socket.c:2204 [inline]
 __se_sys_sendto net/socket.c:2200 [inline]
 __arm64_sys_sendto+0xe4/0x110 net/socket.c:2200
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x90/0x278 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x13c/0x250 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x54/0x70 arch/arm64/kernel/syscall.c:151
 el0_svc+0x4c/0xa8 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x1a0 arch/arm64/kernel/entry.S:600

Freed by task 10200:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x30/0x68 mm/kasan/common.c:68
 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:582
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x48/0x68 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2338 [inline]
 slab_free mm/slub.c:4598 [inline]
 kfree+0x140/0x420 mm/slub.c:4746
 kvfree+0x4c/0x68 mm/util.c:693
 netdev_release+0x94/0xc8 net/core/net-sysfs.c:2034
 device_release+0x98/0x1c0
 kobject_cleanup lib/kobject.c:689 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x2b0/0x438 lib/kobject.c:737
 netdev_run_todo+0xdd8/0xf48 net/core/dev.c:10924
 rtnl_unlock net/core/rtnetlink.c:152 [inline]
 rtnl_net_unlock net/core/rtnetlink.c:209 [inline]
 rtnl_dellink+0x484/0x680 net/core/rtnetlink.c:3526
 rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6901
 netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2542
 rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6928
 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
 netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1347
 netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg net/socket.c:726 [inline]
 ____sys_sendmsg+0x410/0x708 net/socket.c:2583
 ___sys_sendmsg+0x178/0x1d8 net/socket.c:2637
 __sys_sendmsg net/socket.c:2669 [inline]
 __do_sys_sendmsg net/socket.c:2674 [inline]
 __se_sys_sendmsg net/socket.c:2672 [inline]
 __arm64_sys_sendmsg+0x12c/0x1c8 net/socket.c:2672
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x90/0x278 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x13c/0x250 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x54/0x70 arch/arm64/kernel/syscall.c:151
 el0_svc+0x4c/0xa8 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x1a0 arch/arm64/kernel/entry.S:600

The buggy address belongs to the object at ffff0000d768c000
 which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 224 bytes inside of
 freed 4096-byte region [ffff0000d768c000, ffff0000d768d000)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x117688
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff0000c77ef981
flags: 0xbfffe0000000040(head|node=0|zone=2|lastcpupid=0x1ffff)
page_type: f5(slab)
raw: 0bfffe0000000040 ffff0000c000f500 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000040004 00000001f5000000 ffff0000c77ef981
head: 0bfffe0000000040 ffff0000c000f500 dead000000000100 dead000000000122
head: 0000000000000000 0000000000040004 00000001f5000000 ffff0000c77ef981
head: 0bfffe0000000003 fffffdffc35da201 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d768bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff0000d768c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000d768c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff0000d768c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000d768c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Fixes: 8c55facecd ("net: linkwatch: only report IF_OPER_LOWERLAYERDOWN if iflink is actually down")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/netdev/20250102174400.085fd8ac@kernel.org/ [1]
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250106071911.64355-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-01-07 17:50:49 -08:00
Eric DumazetandPaolo Abeni 750e516033 net: avoid potential UAF in default_operstate()
syzbot reported an UAF in default_operstate() [1]

Issue is a race between device and netns dismantles.

After calling __rtnl_unlock() from netdev_run_todo(),
we can not assume the netns of each device is still alive.

Make sure the device is not in NETREG_UNREGISTERED state,
and add an ASSERT_RTNL() before the call to
__dev_get_by_index().

We might move this ASSERT_RTNL() in __dev_get_by_index()
in the future.

[1]

BUG: KASAN: slab-use-after-free in __dev_get_by_index+0x5d/0x110 net/core/dev.c:852
Read of size 8 at addr ffff888043eba1b0 by task syz.0.0/5339

CPU: 0 UID: 0 PID: 5339 Comm: syz.0.0 Not tainted 6.12.0-syzkaller-10296-gaaf20f870da0 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
  __dump_stack lib/dump_stack.c:94 [inline]
  dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
  print_address_description mm/kasan/report.c:378 [inline]
  print_report+0x169/0x550 mm/kasan/report.c:489
  kasan_report+0x143/0x180 mm/kasan/report.c:602
  __dev_get_by_index+0x5d/0x110 net/core/dev.c:852
  default_operstate net/core/link_watch.c:51 [inline]
  rfc2863_policy+0x224/0x300 net/core/link_watch.c:67
  linkwatch_do_dev+0x3e/0x170 net/core/link_watch.c:170
  netdev_run_todo+0x461/0x1000 net/core/dev.c:10894
  rtnl_unlock net/core/rtnetlink.c:152 [inline]
  rtnl_net_unlock include/linux/rtnetlink.h:133 [inline]
  rtnl_dellink+0x760/0x8d0 net/core/rtnetlink.c:3520
  rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6911
  netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2541
  netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
  netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1347
  netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1891
  sock_sendmsg_nosec net/socket.c:711 [inline]
  __sock_sendmsg+0x221/0x270 net/socket.c:726
  ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2583
  ___sys_sendmsg net/socket.c:2637 [inline]
  __sys_sendmsg+0x269/0x350 net/socket.c:2669
  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2a3cb80809
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2a3d9cd058 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f2a3cd45fa0 RCX: 00007f2a3cb80809
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000008
RBP: 00007f2a3cbf393e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2a3cd45fa0 R15: 00007ffd03bc65c8
 </TASK>

Allocated by task 5339:
  kasan_save_stack mm/kasan/common.c:47 [inline]
  kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
  poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
  __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
  kasan_kmalloc include/linux/kasan.h:260 [inline]
  __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4314
  kmalloc_noprof include/linux/slab.h:901 [inline]
  kmalloc_array_noprof include/linux/slab.h:945 [inline]
  netdev_create_hash net/core/dev.c:11870 [inline]
  netdev_init+0x10c/0x250 net/core/dev.c:11890
  ops_init+0x31e/0x590 net/core/net_namespace.c:138
  setup_net+0x287/0x9e0 net/core/net_namespace.c:362
  copy_net_ns+0x33f/0x570 net/core/net_namespace.c:500
  create_new_namespaces+0x425/0x7b0 kernel/nsproxy.c:110
  unshare_nsproxy_namespaces+0x124/0x180 kernel/nsproxy.c:228
  ksys_unshare+0x57d/0xa70 kernel/fork.c:3314
  __do_sys_unshare kernel/fork.c:3385 [inline]
  __se_sys_unshare kernel/fork.c:3383 [inline]
  __x64_sys_unshare+0x38/0x40 kernel/fork.c:3383
  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 12:
  kasan_save_stack mm/kasan/common.c:47 [inline]
  kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
  kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582
  poison_slab_object mm/kasan/common.c:247 [inline]
  __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
  kasan_slab_free include/linux/kasan.h:233 [inline]
  slab_free_hook mm/slub.c:2338 [inline]
  slab_free mm/slub.c:4598 [inline]
  kfree+0x196/0x420 mm/slub.c:4746
  netdev_exit+0x65/0xd0 net/core/dev.c:11992
  ops_exit_list net/core/net_namespace.c:172 [inline]
  cleanup_net+0x802/0xcc0 net/core/net_namespace.c:632
  process_one_work kernel/workqueue.c:3229 [inline]
  process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310
  worker_thread+0x870/0xd30 kernel/workqueue.c:3391
  kthread+0x2f0/0x390 kernel/kthread.c:389
  ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The buggy address belongs to the object at ffff888043eba000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 432 bytes inside of
 freed 2048-byte region [ffff888043eba000, ffff888043eba800)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x43eb8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000040 ffff88801ac42000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000080008 00000001f5000000 0000000000000000
head: 04fff00000000040 ffff88801ac42000 dead000000000122 0000000000000000
head: 0000000000000000 0000000000080008 00000001f5000000 0000000000000000
head: 04fff00000000003 ffffea00010fae01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5339, tgid 5338 (syz.0.0), ts 69674195892, free_ts 69663220888
  set_page_owner include/linux/page_owner.h:32 [inline]
  post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556
  prep_new_page mm/page_alloc.c:1564 [inline]
  get_page_from_freelist+0x3649/0x3790 mm/page_alloc.c:3474
  __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4751
  alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
  alloc_slab_page+0x6a/0x140 mm/slub.c:2408
  allocate_slab+0x5a/0x2f0 mm/slub.c:2574
  new_slab mm/slub.c:2627 [inline]
  ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3815
  __slab_alloc+0x58/0xa0 mm/slub.c:3905
  __slab_alloc_node mm/slub.c:3980 [inline]
  slab_alloc_node mm/slub.c:4141 [inline]
  __do_kmalloc_node mm/slub.c:4282 [inline]
  __kmalloc_noprof+0x2e6/0x4c0 mm/slub.c:4295
  kmalloc_noprof include/linux/slab.h:905 [inline]
  sk_prot_alloc+0xe0/0x210 net/core/sock.c:2165
  sk_alloc+0x38/0x370 net/core/sock.c:2218
  __netlink_create+0x65/0x260 net/netlink/af_netlink.c:629
  __netlink_kernel_create+0x174/0x6f0 net/netlink/af_netlink.c:2015
  netlink_kernel_create include/linux/netlink.h:62 [inline]
  uevent_net_init+0xed/0x2d0 lib/kobject_uevent.c:783
  ops_init+0x31e/0x590 net/core/net_namespace.c:138
  setup_net+0x287/0x9e0 net/core/net_namespace.c:362
page last free pid 1032 tgid 1032 stack trace:
  reset_page_owner include/linux/page_owner.h:25 [inline]
  free_pages_prepare mm/page_alloc.c:1127 [inline]
  free_unref_page+0xdf9/0x1140 mm/page_alloc.c:2657
  __slab_free+0x31b/0x3d0 mm/slub.c:4509
  qlink_free mm/kasan/quarantine.c:163 [inline]
  qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
  kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
  __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
  kasan_slab_alloc include/linux/kasan.h:250 [inline]
  slab_post_alloc_hook mm/slub.c:4104 [inline]
  slab_alloc_node mm/slub.c:4153 [inline]
  kmem_cache_alloc_node_noprof+0x1d9/0x380 mm/slub.c:4205
  __alloc_skb+0x1c3/0x440 net/core/skbuff.c:668
  alloc_skb include/linux/skbuff.h:1323 [inline]
  alloc_skb_with_frags+0xc3/0x820 net/core/skbuff.c:6612
  sock_alloc_send_pskb+0x91a/0xa60 net/core/sock.c:2881
  sock_alloc_send_skb include/net/sock.h:1797 [inline]
  mld_newpack+0x1c3/0xaf0 net/ipv6/mcast.c:1747
  add_grhead net/ipv6/mcast.c:1850 [inline]
  add_grec+0x1492/0x19a0 net/ipv6/mcast.c:1988
  mld_send_initial_cr+0x228/0x4b0 net/ipv6/mcast.c:2234
  ipv6_mc_dad_complete+0x88/0x490 net/ipv6/mcast.c:2245
  addrconf_dad_completed+0x712/0xcd0 net/ipv6/addrconf.c:4342
 addrconf_dad_work+0xdc2/0x16f0
  process_one_work kernel/workqueue.c:3229 [inline]
  process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310

Memory state around the buggy address:
 ffff888043eba080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888043eba100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888043eba180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888043eba200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888043eba280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Fixes: 8c55facecd ("net: linkwatch: only report IF_OPER_LOWERLAYERDOWN if iflink is actually down")
Reported-by: syzbot+1939f24bdb783e9e43d9@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/674f3a18.050a0220.48a03.0041.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://patch.msgid.link/20241203170933.2449307-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2024-12-05 11:57:26 +01:00
Eric DumazetandJakub Kicinski 3e7917c0cd net: linkwatch: use system_unbound_wq
linkwatch_event() grabs possibly very contended RTNL mutex.

system_wq is not suitable for such work.

Inspired by many noisy syzbot reports.

3 locks held by kworker/0:7/5266:
 #0: ffff888015480948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline]
 #0: ffff888015480948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312
 #1: ffffc90003f6fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline]
 , at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312
 #2: ffffffff8fa6f208 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:276

Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20240805085821.1616528-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-06 12:12:53 -07:00
Eric DumazetandDavid S. Miller 6a2968ee1e net: add netdev_set_operstate() helper
dev_base_lock is going away, add netdev_set_operstate() helper
so that hsr does not have to know core internals.

Remove dev_base_lock acquisition from rfc2863_policy()

v3: use an "unsigned int" for dev->operstate,
    so that try_cmpxchg() can work on all arches.
        ( https://lore.kernel.org/oe-kbuild-all/202402081918.OLyGaea3-lkp@intel.com/ )

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2024-02-14 11:20:13 +00:00
Eric DumazetandDavid S. Miller 004d138364 net-sysfs: convert dev->operstate reads to lockless ones
operstate_show() can omit dev_base_lock acquisition only
to read dev->operstate.

Annotate accesses to dev->operstate.

Writers still acquire dev_base_lock for mutual exclusion.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2024-02-14 11:20:13 +00:00
Johannes BergandDavid S. Miller 9a64d4c93e Revert "net: rtnetlink: remove local list in __linkwatch_run_queue()"
This reverts commit b8dbbbc535 ("net: rtnetlink: remove local list
in __linkwatch_run_queue()"). It's evidently broken when there's a
non-urgent work that gets added back, and then the loop can never
finish.

While reverting, add a note about that.

Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: b8dbbbc535 ("net: rtnetlink: remove local list in __linkwatch_run_queue()")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-12-11 10:57:16 +00:00
Johannes BergandJakub Kicinski b8dbbbc535 net: rtnetlink: remove local list in __linkwatch_run_queue()
Due to linkwatch_forget_dev() (and perhaps others?) checking for
list_empty(&dev->link_watch_list), we must have all manipulations
of even the local on-stack list 'wrk' here under spinlock, since
even that list can be reached otherwise via dev->link_watch_list.

This is already the case, but makes this a bit counter-intuitive,
often local lists are used to _not_ have to use locking for their
local use.

Remove the local list as it doesn't seem to serve any purpose.
While at it, move a variable declaration into the loop using it.

Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20231205170011.56576dcc1727.I698b72219d9f6ce789bd209b8f6dffd0ca32a8f2@changeid
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-12-06 19:25:43 -08:00
Johannes BergandJakub Kicinski facd15dfd6 net: core: synchronize link-watch when carrier is queried
There are multiple ways to query for the carrier state: through
rtnetlink, sysfs, and (possibly) ethtool. Synchronize linkwatch
work before these operations so that we don't have a situation
where userspace queries the carrier state between the driver's
carrier off->on transition and linkwatch running and expects it
to work, when really (at least) TX cannot work until linkwatch
has run.

I previously posted a longer explanation of how this applies to
wireless [1] but with this wireless can simply query the state
before sending data, to ensure the kernel is ready for it.

[1] https://lore.kernel.org/all/346b21d87c69f817ea3c37caceb34f1f56255884.camel@sipsolutions.net/

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20231204214706.303c62768415.I1caedccae72ee5a45c9085c5eb49c145ce1c0dd5@changeid
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-12-05 20:16:45 -08:00
Vladimir OlteanandDavid S. Miller 8c55facecd net: linkwatch: only report IF_OPER_LOWERLAYERDOWN if iflink is actually down
RFC 2863 says:

   The lowerLayerDown state is also a refinement on the down state.
   This new state indicates that this interface runs "on top of" one or
   more other interfaces (see ifStackTable) and that this interface is
   down specifically because one or more of these lower-layer interfaces
   are down.

DSA interfaces are virtual network devices, stacked on top of the DSA
master, but they have a physical MAC, with a PHY that reports a real
link status.

But since DSA (perhaps improperly) uses an iflink to describe the
relationship to its master since commit c084080151 ("dsa: set ->iflink
on slave interfaces to the ifindex of the parent"), default_operstate()
will misinterpret this to mean that every time the carrier of a DSA
interface is not ok, it is because of the master being not ok.

In fact, since commit c0a8a9c274 ("net: dsa: automatically bring user
ports down when master goes down"), DSA cannot even in theory be in the
lowerLayerDown state, because it just calls dev_close_many(), thereby
going down, when the master goes down.

We could revert the commit that creates an iflink between a DSA user
port and its master, especially since now we have an alternative
IFLA_DSA_MASTER which has less side effects. But there may be tooling in
use which relies on the iflink, which has existed since 2009.

We could also probably do something local within DSA to overwrite what
rfc2863_policy() did, in a way similar to hsr_set_operstate(), but this
seems like a hack.

What seems appropriate is to follow the iflink, and check the carrier
status of that interface as well. If that's down too, yes, keep
reporting lowerLayerDown, otherwise just down.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-11-16 09:45:00 +00:00
Jakub Kicinski d62607c3fe net: rename reference+tracking helpers
Netdev reference helpers have a dev_ prefix for historic
reasons. Renaming the old helpers would be too much churn
but we can rename the tracking ones which are relatively
recent and should be the default for new code.

Rename:
 dev_hold_track()    -> netdev_hold()
 dev_put_track()     -> netdev_put()
 dev_replace_track() -> netdev_ref_replace()

Link: https://lore.kernel.org/r/20220608043955.919359-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-09 21:52:55 -07:00
Jakub Kicinski 6264f58ca0 net: extract a few internals from netdevice.h
There's a number of functions and static variables used
under net/core/ but not from the outside. We currently
dump most of them into netdevice.h. That bad for many
reasons:
 - netdevice.h is very cluttered, hard to figure out
   what the APIs are;
 - netdevice.h is very long;
 - we have to touch netdevice.h more which causes expensive
   incremental builds.

Create a header under net/core/ and move some declarations.

The new header is also a bit of a catch-all but that's
fine, if we create more specific headers people will
likely over-think where their declaration fit best.
And end up putting them in netdevice.h, again.

More work should be done on splitting netdevice.h into more
targeted headers, but that'd be more time consuming so small
steps.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-07 20:32:09 -07:00
Eric DumazetandDavid S. Miller 4c6c11ea0f net: refine dev_put()/dev_hold() debugging
We are still chasing some syzbot reports where we think a rogue dev_put()
is called with no corresponding prior dev_hold().
Unfortunately it eats a reference on dev->dev_refcnt taken by innocent
dev_hold_track(), meaning that the refcount saturation splat comes
too late to be useful.

Make sure that 'not tracked' dev_put() and dev_hold() better use
CONFIG_NET_DEV_REFCNT_TRACKER=y debug infrastructure:

Prior patch in the series allowed ref_tracker_alloc() and ref_tracker_free()
to be called with a NULL @trackerp parameter, and to use a separate refcount
only to detect too many put() even in the following case:

dev_hold_track(dev, tracker_1, GFP_ATOMIC);
 dev_hold(dev);
 dev_put(dev);
 dev_put(dev); // Should complain loudly here.
dev_put_track(dev, tracker_1); // instead of here

Add clarification about netdev_tracker_alloc() role.

v2: I replaced the dev_put() in linkwatch_do_dev()
    with __dev_put() because callers called netdev_tracker_free().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-05 15:22:45 +00:00
Eric DumazetandJakub Kicinski 123e495ecc net: linkwatch: be more careful about dev->linkwatch_dev_tracker
Apparently a concurrent linkwatch_add_event() could
run while we are in __linkwatch_run_queue().

We need to free dev->linkwatch_dev_tracker tracker
under lweventlist_lock protection to avoid this race.

syzbot report:
[   77.935949][ T3661] reference already released.
[   77.941015][ T3661] allocated in:
[   77.944482][ T3661]  linkwatch_fire_event+0x202/0x260
[   77.950318][ T3661]  netif_carrier_on+0x9c/0x100
[   77.955120][ T3661]  __ieee80211_sta_join_ibss+0xc52/0x1590
[   77.960888][ T3661]  ieee80211_sta_create_ibss.cold+0xd2/0x11f
[   77.966908][ T3661]  ieee80211_ibss_work.cold+0x30e/0x60f
[   77.972483][ T3661]  ieee80211_iface_work+0xb70/0xd00
[   77.977715][ T3661]  process_one_work+0x9ac/0x1680
[   77.982671][ T3661]  worker_thread+0x652/0x11c0
[   77.987371][ T3661]  kthread+0x405/0x4f0
[   77.991465][ T3661]  ret_from_fork+0x1f/0x30
[   77.995895][ T3661] freed in:
[   77.999006][ T3661]  linkwatch_do_dev+0x96/0x160
[   78.004014][ T3661]  __linkwatch_run_queue+0x233/0x6a0
[   78.009496][ T3661]  linkwatch_event+0x4a/0x60
[   78.014099][ T3661]  process_one_work+0x9ac/0x1680
[   78.019034][ T3661]  worker_thread+0x652/0x11c0
[   78.023719][ T3661]  kthread+0x405/0x4f0
[   78.027810][ T3661]  ret_from_fork+0x1f/0x30
[   78.042541][ T3661] ------------[ cut here ]------------
[   78.048253][ T3661] WARNING: CPU: 0 PID: 3661 at lib/ref_tracker.c:120 ref_tracker_free.cold+0x110/0x14e
[   78.062364][ T3661] Modules linked in:
[   78.066424][ T3661] CPU: 0 PID: 3661 Comm: kworker/0:5 Not tainted 5.16.0-rc4-next-20211210-syzkaller #0
[   78.076075][ T3661] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   78.090648][ T3661] Workqueue: events linkwatch_event
[   78.095890][ T3661] RIP: 0010:ref_tracker_free.cold+0x110/0x14e
[   78.102191][ T3661] Code: ea 03 48 c1 e0 2a 0f b6 04 02 84 c0 74 04 3c 03 7e 4c 8b 7b 18 e8 6b 54 e9 fa e8 26 4d 57 f8 4c 89 ee 48 89 ef e8 fb 33 36 00 <0f> 0b 41 bd ea ff ff ff e9 bd 60 e9 fa 4c 89 f7 e8 16 45 a2 f8 e9
[   78.127211][ T3661] RSP: 0018:ffffc90002b5fb18 EFLAGS: 00010246
[   78.133684][ T3661] RAX: 0000000000000000 RBX: ffff88807467f700 RCX: 0000000000000000
[   78.141928][ T3661] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000001
[   78.150087][ T3661] RBP: ffff888057e105b8 R08: 0000000000000001 R09: ffffffff8ffa1967
[   78.158211][ T3661] R10: 0000000000000001 R11: 0000000000000000 R12: 1ffff9200056bf65
[   78.166204][ T3661] R13: 0000000000000292 R14: ffff88807467f718 R15: 00000000c0e0008c
[   78.174321][ T3661] FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
[   78.183310][ T3661] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   78.190156][ T3661] CR2: 000000c000208800 CR3: 000000007f7b5000 CR4: 00000000003506f0
[   78.198235][ T3661] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   78.206214][ T3661] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   78.214328][ T3661] Call Trace:
[   78.217679][ T3661]  <TASK>
[   78.220621][ T3661]  ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70
[   78.226981][ T3661]  ? nlmsg_notify+0xbe/0x280
[   78.231607][ T3661]  ? ref_tracker_dir_exit+0x330/0x330
[   78.237654][ T3661]  ? linkwatch_do_dev+0x96/0x160
[   78.242628][ T3661]  ? __linkwatch_run_queue+0x233/0x6a0
[   78.248170][ T3661]  ? linkwatch_event+0x4a/0x60
[   78.252946][ T3661]  ? process_one_work+0x9ac/0x1680
[   78.258136][ T3661]  ? worker_thread+0x853/0x11c0
[   78.263020][ T3661]  ? kthread+0x405/0x4f0
[   78.267905][ T3661]  ? ret_from_fork+0x1f/0x30
[   78.272670][ T3661]  ? netdev_state_change+0xa1/0x130
[   78.278019][ T3661]  ? netdev_exit+0xd0/0xd0
[   78.282466][ T3661]  ? dev_activate+0x420/0xa60
[   78.287261][ T3661]  linkwatch_do_dev+0x96/0x160
[   78.292043][ T3661]  __linkwatch_run_queue+0x233/0x6a0
[   78.297505][ T3661]  ? linkwatch_do_dev+0x160/0x160
[   78.302561][ T3661]  linkwatch_event+0x4a/0x60
[   78.307225][ T3661]  process_one_work+0x9ac/0x1680
[   78.312292][ T3661]  ? pwq_dec_nr_in_flight+0x2a0/0x2a0
[   78.317757][ T3661]  ? rwlock_bug.part.0+0x90/0x90
[   78.322726][ T3661]  ? _raw_spin_lock_irq+0x41/0x50
[   78.327844][ T3661]  worker_thread+0x853/0x11c0
[   78.332543][ T3661]  ? process_one_work+0x1680/0x1680
[   78.338500][ T3661]  kthread+0x405/0x4f0
[   78.342610][ T3661]  ? set_kthread_struct+0x130/0x130

Fixes: 63f13937cb ("net: linkwatch: add net device refcount tracker")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20211214051955.3569843-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-14 18:45:58 -08:00
Eric DumazetandJakub Kicinski 63f13937cb net: linkwatch: add net device refcount tracker
Add a netdevice_tracker inside struct net_device, to track
the self reference when a device is in lweventlist.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-06 16:05:44 -08:00
Sebastian Andrzej SiewiorandDavid S. Miller fd888e85fe net: Write lock dev_base_lock without disabling bottom halves.
The writer acquires dev_base_lock with disabled bottom halves.
The reader can acquire dev_base_lock without disabling bottom halves
because there is no writer in softirq context.

On PREEMPT_RT the softirqs are preemptible and local_bh_disable() acts
as a lock to ensure that resources, that are protected by disabling
bottom halves, remain protected.
This leads to a circular locking dependency if the lock acquired with
disabled bottom halves (as in write_lock_bh()) and somewhere else with
enabled bottom halves (as by read_lock() in netstat_show()) followed by
disabling bottom halves (cxgb_get_stats() -> t4_wr_mbox_meat_timeout()
-> spin_lock_bh()). This is the reverse locking order.

All read_lock() invocation are from sysfs callback which are not invoked
from softirq context. Therefore there is no need to disable bottom
halves while acquiring a write lock.

Acquire the write lock of dev_base_lock without disabling bottom halves.

Reported-by: Pei Zhang <pezhang@redhat.com>
Reported-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-29 12:12:36 +00:00
Willy TarreauandJakub Kicinski 6922110d15 net: linkwatch: fix failure to restore device state across suspend/resume
After migrating my laptop from 4.19-LTS to 5.4-LTS a while ago I noticed
that my Ethernet port to which a bond and a VLAN interface are attached
appeared to remain up after resuming from suspend with the cable unplugged
(and that problem still persists with 5.10-LTS).

It happens that the following happens:

  - the network driver (e1000e here) prepares to suspend, calls e1000e_down()
    which calls netif_carrier_off() to signal that the link is going down.
  - netif_carrier_off() adds a link_watch event to the list of events for
    this device
  - the device is completely stopped.
  - the machine suspends
  - the cable is unplugged and the machine brought to another location
  - the machine is resumed
  - the queued linkwatch events are processed for the device
  - the device doesn't yet have the __LINK_STATE_PRESENT bit and its events
    are silently dropped
  - the device is resumed with its link down
  - the upper VLAN and bond interfaces are never notified that the link had
    been turned down and remain up
  - the only way to provoke a change is to physically connect the machine
    to a port and possibly unplug it.

The state after resume looks like this:
  $ ip -br li | egrep 'bond|eth'
  bond0            UP             e8:6a:64:64:64:64 <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP>
  eth0             DOWN           e8:6a:64:64:64:64 <NO-CARRIER,BROADCAST,MULTICAST,SLAVE,UP>
  eth0.2@eth0      UP             e8:6a:64:64:64:64 <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP>

Placing an explicit call to netdev_state_change() either in the suspend
or the resume code in the NIC driver worked around this but the solution
is not satisfying.

The issue in fact really is in link_watch that loses events while it
ought not to. It happens that the test for the device being present was
added by commit 124eee3f69 ("net: linkwatch: add check for netdevice
being present to linkwatch_do_dev") in 4.20 to avoid an access to
devices that are not present.

Instead of dropping events, this patch proceeds slightly differently by
postponing their handling so that they happen after the device is fully
resumed.

Fixes: 124eee3f69 ("net: linkwatch: add check for netdevice being present to linkwatch_do_dev")
Link: https://lists.openwall.net/netdev/2018/03/15/62
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20210809160628.22623-1-w@1wt.eu
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-11 14:43:16 -07:00
Andrew LunnandDavid S. Miller eec517cdb4 net: Add IF_OPER_TESTING
RFC 2863 defines the operational state testing. Add support for this
state, both as a IF_LINK_MODE_ and __LINK_STATE_.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-20 12:43:24 -07:00
Yunsheng LinandDavid S. Miller 27ba4059e0 net: link_watch: prevent starvation when processing linkwatch wq
When user has configured a large number of virtual netdev, such
as 4K vlans, the carrier on/off operation of the real netdev
will also cause it's virtual netdev's link state to be processed
in linkwatch. Currently, the processing is done in a work queue,
which may cause rtnl locking starvation problem and worker
starvation problem for other work queue, such as irqfd_inject wq.

This patch releases the cpu when link watch worker has processed
a fixed number of netdev' link watch event, and schedule the
work queue again when there is still link watch event remaining.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-07-01 19:02:47 -07:00
Thomas GleixnerandGreg Kroah-Hartman 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00
Heiner KallweitandDavid S. Miller 124eee3f69 net: linkwatch: add check for netdevice being present to linkwatch_do_dev
When bringing down the netdevice (incl. detaching it) and calling
netif_carrier_off directly or indirectly the latter triggers an
asynchronous linkwatch event.
This linkwatch event eventually may fail to access chip registers in
the ndo_get_stats/ndo_get_stats64 callback because the device isn't
accessible any longer, see call trace in [0].

To prevent this scenario don't check for IFF_UP only, but also make
sure that the netdevice is present.

[0] https://lists.openwall.net/netdev/2018/03/15/62

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-19 21:06:46 -07:00
Roopa PrabhuandDavid S. Miller b76f4189df net: link_watch: mark bonding link events urgent
It takes 1sec for bond link down notification to hit user-space
when all slaves of the bond go down. 1sec is too long for
protocol daemons in user-space relying on bond notification
to recover (eg: multichassis lag implementations in user-space).
Since the link event code already marks team device port link events
 as urgent, this patch moves the code to cover all lag ports and master.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-23 19:43:30 -05:00