linux-stable.git/net/core/drop_monitor.c, branch linux-5.17.y Linux kernel stable tree drop_monitor: fix data-race in dropmon_net_event / trace_napi_poll_hit 2022-02-11T11:20:32+00:00 Eric Dumazet edumazet@google.com 2022-02-10T17:13:31+00:00 dcd54265c8bc14bd023815e36e2d5f9d66ee1fee trace_napi_poll_hit() is reading stat->dev while another thread can write on it from dropmon_net_event() Use READ_ONCE()/WRITE_ONCE() here, RCU rules are properly enforced already, we only have to take care of load/store tearing. BUG: KCSAN: data-race in dropmon_net_event / trace_napi_poll_hit write to 0xffff88816f3ab9c0 of 8 bytes by task 20260 on cpu 1: dropmon_net_event+0xb8/0x2b0 net/core/drop_monitor.c:1579 notifier_call_chain kernel/notifier.c:84 [inline] raw_notifier_call_chain+0x53/0xb0 kernel/notifier.c:392 call_netdevice_notifiers_info net/core/dev.c:1919 [inline] call_netdevice_notifiers_extack net/core/dev.c:1931 [inline] call_netdevice_notifiers net/core/dev.c:1945 [inline] unregister_netdevice_many+0x867/0xfb0 net/core/dev.c:10415 ip_tunnel_delete_nets+0x24a/0x280 net/ipv4/ip_tunnel.c:1123 vti_exit_batch_net+0x2a/0x30 net/ipv4/ip_vti.c:515 ops_exit_list net/core/net_namespace.c:173 [inline] cleanup_net+0x4dc/0x8d0 net/core/net_namespace.c:597 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307 worker_thread+0x616/0xa70 kernel/workqueue.c:2454 kthread+0x1bf/0x1e0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 read to 0xffff88816f3ab9c0 of 8 bytes by interrupt on cpu 0: trace_napi_poll_hit+0x89/0x1c0 net/core/drop_monitor.c:292 trace_napi_poll include/trace/events/napi.h:14 [inline] __napi_poll+0x36b/0x3f0 net/core/dev.c:6366 napi_poll net/core/dev.c:6432 [inline] net_rx_action+0x29e/0x650 net/core/dev.c:6519 __do_softirq+0x158/0x2de kernel/softirq.c:558 do_softirq+0xb1/0xf0 kernel/softirq.c:459 __local_bh_enable_ip+0x68/0x70 kernel/softirq.c:383 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline] _raw_spin_unlock_bh+0x33/0x40 kernel/locking/spinlock.c:210 spin_unlock_bh include/linux/spinlock.h:394 [inline] ptr_ring_consume_bh include/linux/ptr_ring.h:367 [inline] wg_packet_decrypt_worker+0x73c/0x780 drivers/net/wireguard/receive.c:506 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307 worker_thread+0x616/0xa70 kernel/workqueue.c:2454 kthread+0x1bf/0x1e0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 value changed: 0xffff88815883e000 -> 0x0000000000000000 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 26435 Comm: kworker/0:1 Not tainted 5.17.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: wg-crypt-wg2 wg_packet_decrypt_worker Fixes: 4ea7e38696c7 ("dropmon: add ability to detect when hardware dropsrxpackets") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neil Horman <nhorman@tuxdriver.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
trace_napi_poll_hit() is reading stat->dev while another thread can write
on it from dropmon_net_event()

Use READ_ONCE()/WRITE_ONCE() here, RCU rules are properly enforced already,
we only have to take care of load/store tearing.

BUG: KCSAN: data-race in dropmon_net_event / trace_napi_poll_hit

write to 0xffff88816f3ab9c0 of 8 bytes by task 20260 on cpu 1:
 dropmon_net_event+0xb8/0x2b0 net/core/drop_monitor.c:1579
 notifier_call_chain kernel/notifier.c:84 [inline]
 raw_notifier_call_chain+0x53/0xb0 kernel/notifier.c:392
 call_netdevice_notifiers_info net/core/dev.c:1919 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:1931 [inline]
 call_netdevice_notifiers net/core/dev.c:1945 [inline]
 unregister_netdevice_many+0x867/0xfb0 net/core/dev.c:10415
 ip_tunnel_delete_nets+0x24a/0x280 net/ipv4/ip_tunnel.c:1123
 vti_exit_batch_net+0x2a/0x30 net/ipv4/ip_vti.c:515
 ops_exit_list net/core/net_namespace.c:173 [inline]
 cleanup_net+0x4dc/0x8d0 net/core/net_namespace.c:597
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

read to 0xffff88816f3ab9c0 of 8 bytes by interrupt on cpu 0:
 trace_napi_poll_hit+0x89/0x1c0 net/core/drop_monitor.c:292
 trace_napi_poll include/trace/events/napi.h:14 [inline]
 __napi_poll+0x36b/0x3f0 net/core/dev.c:6366
 napi_poll net/core/dev.c:6432 [inline]
 net_rx_action+0x29e/0x650 net/core/dev.c:6519
 __do_softirq+0x158/0x2de kernel/softirq.c:558
 do_softirq+0xb1/0xf0 kernel/softirq.c:459
 __local_bh_enable_ip+0x68/0x70 kernel/softirq.c:383
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline]
 _raw_spin_unlock_bh+0x33/0x40 kernel/locking/spinlock.c:210
 spin_unlock_bh include/linux/spinlock.h:394 [inline]
 ptr_ring_consume_bh include/linux/ptr_ring.h:367 [inline]
 wg_packet_decrypt_worker+0x73c/0x780 drivers/net/wireguard/receive.c:506
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

value changed: 0xffff88815883e000 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 26435 Comm: kworker/0:1 Not tainted 5.17.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: wg-crypt-wg2 wg_packet_decrypt_worker

Fixes: 4ea7e38696c7 ("dropmon: add ability to detect when hardware dropsrxpackets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net: skb: introduce kfree_skb_reason() 2022-01-10T00:30:34+00:00 Menglong Dong imagedong@tencent.com 2022-01-09T06:36:26+00:00 c504e5c2f9648a1e5c2be01e8c3f59d394192bd3 Introduce the interface kfree_skb_reason(), which is able to pass the reason why the skb is dropped to 'kfree_skb' tracepoint. Add the 'reason' field to 'trace_kfree_skb', therefor user can get more detail information about abnormal skb with 'drop_monitor' or eBPF. All drop reasons are defined in the enum 'skb_drop_reason', and they will be print as string in 'kfree_skb' tracepoint in format of 'reason: XXX'. ( Maybe the reasons should be defined in a uapi header file, so that user space can use them? ) Signed-off-by: Menglong Dong <imagedong@tencent.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Introduce the interface kfree_skb_reason(), which is able to pass
the reason why the skb is dropped to 'kfree_skb' tracepoint.

Add the 'reason' field to 'trace_kfree_skb', therefor user can get
more detail information about abnormal skb with 'drop_monitor' or
eBPF.

All drop reasons are defined in the enum 'skb_drop_reason', and
they will be print as string in 'kfree_skb' tracepoint in format
of 'reason: XXX'.

( Maybe the reasons should be defined in a uapi header file, so that
user space can use them? )

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
drop_monitor: add net device refcount tracker 2021-12-07T00:05:10+00:00 Eric Dumazet edumazet@google.com 2021-12-05T04:22:02+00:00 4dbd24f65c60259ce5d1563433ecaf5fab693c83 We want to track all dev_hold()/dev_put() to ease leak hunting. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
We want to track all dev_hold()/dev_put() to ease leak hunting.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net: Remove redundant if statements 2021-08-05T12:27:50+00:00 Yajun Deng yajun.deng@linux.dev 2021-08-05T11:55:27+00:00 1160dfa178eb848327e9dec39960a735f4dc1685 The 'if (dev)' statement already move into dev_{put , hold}, so remove redundant if statements. Signed-off-by: Yajun Deng <yajun.deng@linux.dev> Signed-off-by: David S. Miller <davem@davemloft.net> 
The 'if (dev)' statement already move into dev_{put , hold}, so remove
redundant if statements.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2021-03-25T22:31:22+00:00 David S. Miller davem@davemloft.net 2021-03-25T22:31:22+00:00 efd13b71a3fa31413f8d15342e01d44b60b0a432 Signed-off-by: David S. Miller <davem@davemloft.net> 
Signed-off-by: David S. Miller <davem@davemloft.net>
/net/core/: fix misspellings using codespell tool 2021-03-19T02:13:41+00:00 Xiong Zhenwu xiong.zhenwu@zte.com.cn 2021-03-18T11:52:13+00:00 a835f9034efbb699f307575bead2607c2fbc93ac A typo is found out by codespell tool in 1734th line of drop_monitor.c: $ codespell ./net/core/ ./net/core/drop_monitor.c:1734: guarnateed ==> guaranteed Fix a typo found by codespell. Signed-off-by: Xiong Zhenwu <xiong.zhenwu@zte.com.cn> Signed-off-by: David S. Miller <davem@davemloft.net> 
A typo is found out by codespell tool in 1734th line of drop_monitor.c:

$ codespell ./net/core/
./net/core/drop_monitor.c:1734: guarnateed  ==> guaranteed

Fix a typo found by codespell.

Signed-off-by: Xiong Zhenwu <xiong.zhenwu@zte.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
drop_monitor: Perform cleanup upon probe registration failure 2021-03-10T23:19:02+00:00 Ido Schimmel idosch@nvidia.com 2021-03-10T10:28:01+00:00 9398e9c0b1d44eeb700e9e766c02bcc765c82570 In the rare case that drop_monitor fails to register its probe on the 'napi_poll' tracepoint, it will not deactivate its hysteresis timer as part of the error path. If the hysteresis timer was armed by the shortly lived 'kfree_skb' probe and user space retries to initiate tracing, a warning will be emitted for trying to initialize an active object [1]. Fix this by properly undoing all the operations that were done prior to probe registration, in both software and hardware code paths. Note that syzkaller managed to fail probe registration by injecting a slab allocation failure [2]. [1] ODEBUG: init active (active state 0) object type: timer_list hint: sched_send_work+0x0/0x60 include/linux/list.h:135 WARNING: CPU: 1 PID: 8649 at lib/debugobjects.c:505 debug_print_object+0x16e/0x250 lib/debugobjects.c:505 Modules linked in: CPU: 1 PID: 8649 Comm: syz-executor.0 Not tainted 5.11.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:debug_print_object+0x16e/0x250 lib/debugobjects.c:505 [...] Call Trace: __debug_object_init+0x524/0xd10 lib/debugobjects.c:588 debug_timer_init kernel/time/timer.c:722 [inline] debug_init kernel/time/timer.c:770 [inline] init_timer_key+0x2d/0x340 kernel/time/timer.c:814 net_dm_trace_on_set net/core/drop_monitor.c:1111 [inline] set_all_monitor_traces net/core/drop_monitor.c:1188 [inline] net_dm_monitor_start net/core/drop_monitor.c:1295 [inline] net_dm_cmd_trace+0x720/0x1220 net/core/drop_monitor.c:1339 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739 genl_family_rcv_msg net/netlink/genetlink.c:783 [inline] genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:800 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2502 genl_rcv+0x24/0x40 net/netlink/genetlink.c:811 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:672 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2348 ___sys_sendmsg+0xf3/0x170 net/socket.c:2402 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2435 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae [2] FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 1 CPU: 1 PID: 8645 Comm: syz-executor.0 Not tainted 5.11.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: dump_stack+0xfa/0x151 should_fail.cold+0x5/0xa should_failslab+0x5/0x10 __kmalloc+0x72/0x3f0 tracepoint_add_func+0x378/0x990 tracepoint_probe_register+0x9c/0xe0 net_dm_cmd_trace+0x7fc/0x1220 genl_family_rcv_msg_doit+0x228/0x320 genl_rcv_msg+0x328/0x580 netlink_rcv_skb+0x153/0x420 genl_rcv+0x24/0x40 netlink_unicast+0x533/0x7d0 netlink_sendmsg+0x856/0xd90 sock_sendmsg+0xcf/0x120 ____sys_sendmsg+0x6e8/0x810 ___sys_sendmsg+0xf3/0x170 __sys_sendmsg+0xe5/0x1b0 do_syscall_64+0x2d/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: 70c69274f354 ("drop_monitor: Initialize timer and work item upon tracing enable") Fixes: 8ee2267ad33e ("drop_monitor: Convert to using devlink tracepoint") Reported-by: syzbot+779559d6503f3a56213d@syzkaller.appspotmail.com Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: Jiri Pirko <jiri@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
In the rare case that drop_monitor fails to register its probe on the
'napi_poll' tracepoint, it will not deactivate its hysteresis timer as
part of the error path. If the hysteresis timer was armed by the shortly
lived 'kfree_skb' probe and user space retries to initiate tracing, a
warning will be emitted for trying to initialize an active object [1].

Fix this by properly undoing all the operations that were done prior to
probe registration, in both software and hardware code paths.

Note that syzkaller managed to fail probe registration by injecting a
slab allocation failure [2].

[1]
ODEBUG: init active (active state 0) object type: timer_list hint: sched_send_work+0x0/0x60 include/linux/list.h:135
WARNING: CPU: 1 PID: 8649 at lib/debugobjects.c:505 debug_print_object+0x16e/0x250 lib/debugobjects.c:505
Modules linked in:
CPU: 1 PID: 8649 Comm: syz-executor.0 Not tainted 5.11.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:debug_print_object+0x16e/0x250 lib/debugobjects.c:505
[...]
Call Trace:
 __debug_object_init+0x524/0xd10 lib/debugobjects.c:588
 debug_timer_init kernel/time/timer.c:722 [inline]
 debug_init kernel/time/timer.c:770 [inline]
 init_timer_key+0x2d/0x340 kernel/time/timer.c:814
 net_dm_trace_on_set net/core/drop_monitor.c:1111 [inline]
 set_all_monitor_traces net/core/drop_monitor.c:1188 [inline]
 net_dm_monitor_start net/core/drop_monitor.c:1295 [inline]
 net_dm_cmd_trace+0x720/0x1220 net/core/drop_monitor.c:1339
 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739
 genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
 genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:800
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2502
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:811
 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2348
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2402
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2435
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

[2]
 FAULT_INJECTION: forcing a failure.
 name failslab, interval 1, probability 0, space 0, times 1
 CPU: 1 PID: 8645 Comm: syz-executor.0 Not tainted 5.11.0-syzkaller #0
 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 Call Trace:
  dump_stack+0xfa/0x151
  should_fail.cold+0x5/0xa
  should_failslab+0x5/0x10
  __kmalloc+0x72/0x3f0
  tracepoint_add_func+0x378/0x990
  tracepoint_probe_register+0x9c/0xe0
  net_dm_cmd_trace+0x7fc/0x1220
  genl_family_rcv_msg_doit+0x228/0x320
  genl_rcv_msg+0x328/0x580
  netlink_rcv_skb+0x153/0x420
  genl_rcv+0x24/0x40
  netlink_unicast+0x533/0x7d0
  netlink_sendmsg+0x856/0xd90
  sock_sendmsg+0xcf/0x120
  ____sys_sendmsg+0x6e8/0x810
  ___sys_sendmsg+0xf3/0x170
  __sys_sendmsg+0xe5/0x1b0
  do_syscall_64+0x2d/0x70
  entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: 70c69274f354 ("drop_monitor: Initialize timer and work item upon tracing enable")
Fixes: 8ee2267ad33e ("drop_monitor: Convert to using devlink tracepoint")
Reported-by: syzbot+779559d6503f3a56213d@syzkaller.appspotmail.com
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
genetlink: move to smaller ops wherever possible 2020-10-03T02:11:11+00:00 Jakub Kicinski kuba@kernel.org 2020-10-02T21:49:54+00:00 66a9b9287d2447a91cef2fafc648dee32186f708 Bulk of the genetlink users can use smaller ops, move them. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: David S. Miller <davem@davemloft.net> 
Bulk of the genetlink users can use smaller ops, move them.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
drop_monitor: Filter control packets in drop monitor 2020-10-01T01:01:26+00:00 Ido Schimmel idosch@mellanox.com 2020-09-29T08:15:55+00:00 93e155967ccc053b71d408edf8c0142199df5c8c Previously, devlink called into drop monitor in order to report hardware originated drops / exceptions. devlink intentionally filtered control packets and did not pass them to drop monitor as they were not dropped by the underlying hardware. Now drop monitor registers its probe on a generic 'devlink_trap_report' tracepoint and should therefore perform this filtering itself instead of having devlink do that. Add the trap type as metadata and have drop monitor ignore control packets. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Previously, devlink called into drop monitor in order to report hardware
originated drops / exceptions. devlink intentionally filtered control
packets and did not pass them to drop monitor as they were not dropped
by the underlying hardware.

Now drop monitor registers its probe on a generic 'devlink_trap_report'
tracepoint and should therefore perform this filtering itself instead of
having devlink do that.

Add the trap type as metadata and have drop monitor ignore control
packets.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drop_monitor: Remove duplicate struct 2020-10-01T01:01:26+00:00 Ido Schimmel idosch@mellanox.com 2020-09-29T08:15:54+00:00 a848c05f4bb6c2db9e686e2440454af811e6d2e5 'struct net_dm_hw_metadata' is a duplicate of 'struct devlink_trap_metadata'. Remove the former and simplify the code. Signed-off-by: Ido Schimmel <idosch@mellanox.com> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
'struct net_dm_hw_metadata' is a duplicate of 'struct
devlink_trap_metadata'.

Remove the former and simplify the code.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>