linux-toradex.git/drivers/net/netdevsim/fib.c, branch v5.17-rc5

ipv6: fix data-race in fib6_info_hw_flags_set / fib6_purge_rt

2022-02-17T17:48:24+00:00

Because fib6_info_hw_flags_set() is called without any synchronization,
all accesses to gi6->offload, fi->trap and fi->offload_failed
need some basic protection like READ_ONCE()/WRITE_ONCE().

BUG: KCSAN: data-race in fib6_info_hw_flags_set / fib6_purge_rt

read to 0xffff8881087d5886 of 1 bytes by task 13953 on cpu 0:
 fib6_drop_pcpu_from net/ipv6/ip6_fib.c:1007 [inline]
 fib6_purge_rt+0x4f/0x580 net/ipv6/ip6_fib.c:1033
 fib6_del_route net/ipv6/ip6_fib.c:1983 [inline]
 fib6_del+0x696/0x890 net/ipv6/ip6_fib.c:2028
 __ip6_del_rt net/ipv6/route.c:3876 [inline]
 ip6_del_rt+0x83/0x140 net/ipv6/route.c:3891
 __ipv6_dev_ac_dec+0x2b5/0x370 net/ipv6/anycast.c:374
 ipv6_dev_ac_dec net/ipv6/anycast.c:387 [inline]
 __ipv6_sock_ac_close+0x141/0x200 net/ipv6/anycast.c:207
 ipv6_sock_ac_close+0x79/0x90 net/ipv6/anycast.c:220
 inet6_release+0x32/0x50 net/ipv6/af_inet6.c:476
 __sock_release net/socket.c:650 [inline]
 sock_close+0x6c/0x150 net/socket.c:1318
 __fput+0x295/0x520 fs/file_table.c:280
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x160/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

write to 0xffff8881087d5886 of 1 bytes by task 1912 on cpu 1:
 fib6_info_hw_flags_set+0x155/0x3b0 net/ipv6/route.c:6230
 nsim_fib6_rt_hw_flags_set drivers/net/netdevsim/fib.c:668 [inline]
 nsim_fib6_rt_add drivers/net/netdevsim/fib.c:691 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:756 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:853 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:886 [inline]
 nsim_fib_event_work+0x284f/0x2cf0 drivers/net/netdevsim/fib.c:1477
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x2c7/0x2e0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

value changed: 0x22 -> 0x2a

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1912 Comm: kworker/1:3 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events nsim_fib_event_work

Fixes: 0c5fcf9e249e ("IPv6: Add "offload failed" indication to routes")
Fixes: bb3c4ab93e44 ("ipv6: Add "offload" and "trap" indications to routes")
Signed-off-by: Eric Dumazet 
Cc: Amit Cohen 
Cc: Ido Schimmel 
Reported-by: syzbot 
Link: https://lore.kernel.org/r/20220216173217.3792411-2-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski

netdevsim: make array res_ids static const, makes object smaller

2021-08-02T16:12:24+00:00

Don't populate the array res_ids on the stack but instead it
static const. Makes the object code smaller by 14 bytes.

Before:
   text    data     bss     dec     hex filename
  50833    8314     256   59403    e80b ./drivers/net/netdevsim/fib.o

After:
   text    data     bss     dec     hex filename
  50755    8378     256   59389    e7fd ./drivers/net/netdevsim/fib.o

(gcc version 10.2.0)

Signed-off-by: Colin Ian King 
Link: https://lore.kernel.org/r/20210801065328.138906-1-colin.king@canonical.com
Signed-off-by: Jakub Kicinski

netdevsim: remove unneeded semicolon

2021-04-06T23:27:33+00:00

Eliminate the following coccicheck warning:
 drivers/net/netdevsim/fib.c:569:2-3: Unneeded semicolon

Signed-off-by: Qiheng Lin 
Acked-by: Jakub Kicinski 
Signed-off-by: David S. Miller

netdevsim: Allow reporting activity on nexthop buckets

2021-03-13T01:44:10+00:00

A key component of the resilient hashing algorithm is the hash buckets'
activity. If a bucket is active, it will not be populated with a new
nexthop in order not to break existing flows. Therefore, in order to
easily and thoroughly test the algorithm, we need to be in full control
over the reported activity.

Add a debugfs interface that allows user space to have netdevsim report
a nexthop bucket within a resilient nexthop group as active. For
example:

 # echo 10 23 > /sys/kernel/debug/netdevsim/netdevsim10/fib/nexthop_bucket_activity

Will mark bucket 23 in nexthop group 10 as active.

Signed-off-by: Ido Schimmel 
Reviewed-by: Petr Machata 
Signed-off-by: Petr Machata 
Signed-off-by: David S. Miller

netdevsim: Add support for resilient nexthop groups

2021-03-13T01:44:10+00:00

Allow resilient nexthop groups to be programmed and account their
occupancy according to their number of buckets. The nexthop group itself
as well as its buckets are marked with hardware flags (i.e.,
'RTNH_F_TRAP').

Replacement of a single nexthop bucket can fail using the following
debugfs knob:

 # cat /sys/kernel/debug/netdevsim/netdevsim10/fib/fail_nexthop_bucket_replace
 N
 # echo 1 > /sys/kernel/debug/netdevsim/netdevsim10/fib/fail_nexthop_bucket_replace
 # cat /sys/kernel/debug/netdevsim/netdevsim10/fib/fail_nexthop_bucket_replace
 Y

Replacement of a resilient nexthop group can fail using the following
debugfs knob:

 # cat /sys/kernel/debug/netdevsim/netdevsim10/fib/fail_res_nexthop_group_replace
 N
 # echo 1 > /sys/kernel/debug/netdevsim/netdevsim10/fib/fail_res_nexthop_group_replace
 # cat /sys/kernel/debug/netdevsim/netdevsim10/fib/fail_res_nexthop_group_replace
 Y

This enables testing of various error paths.

Signed-off-by: Ido Schimmel 
Reviewed-by: Petr Machata 
Signed-off-by: Petr Machata 
Signed-off-by: David S. Miller

netdevsim: Create a helper for setting nexthop hardware flags

2021-03-13T01:44:10+00:00

Instead of calling nexthop_set_hw_flags(), call a helper. It will be
used to also set nexthop bucket flags in a subsequent patch.

Signed-off-by: Ido Schimmel 
Reviewed-by: Petr Machata 
Signed-off-by: Petr Machata 
Signed-off-by: David S. Miller

netdevsim: fib: Introduce a lock to guard nexthop hashtable

2021-03-13T01:44:10+00:00

Currently netdevsim relies on RTNL to maintain exclusivity in accessing the
nexthop hash table. However, bucket notification may be called without RTNL
having been held. Instead, introduce a custom lock to guard the table.

Signed-off-by: Petr Machata 
Reviewed-by: Ido Schimmel 
Signed-off-by: David S. Miller

netdevsim: fib: Remove redundant code

2021-03-11T22:32:48+00:00

Fix the following coccicheck warnings:

./drivers/net/netdevsim/fib.c:874:5-8: Unneeded variable: "err". Return
"0" on line 889.

Reported-by: Abaci Robot 
Signed-off-by: Jiapeng Chong 
Reviewed-by: Jakub Kicinski 
Signed-off-by: David S. Miller

netdevsim: fib: Add debugfs to debug route offload failure

2021-02-09T00:47:03+00:00

Add "fail_route_offload" flag to disallow offloading routes.
It is needed to test "offload failed" notifications.

Create the flag as part of nsim_fib_create() under fib directory and set
it to false by default.

When FIB_EVENT_ENTRY_{REPLACE, APPEND} are triggered and
"fail_route_offload" value is true, set the appropriate hardware flag to
make the kernel emit RTM_NEWROUTE notification with RTM_F_OFFLOAD_FAILED
flag.

Signed-off-by: Amit Cohen 
Signed-off-by: Ido Schimmel 
Signed-off-by: David S. Miller

netdevsim: fib: Do not warn if route was not found for several events

2021-02-09T00:47:03+00:00

The next patch will add the ability to fail route offload controlled by
debugfs variable called "fail_route_offload".

If we vetoed the addition, we might get a delete or append notification
for a route we do not have. Therefore, do not warn if route was not found.

Signed-off-by: Amit Cohen 
Signed-off-by: Ido Schimmel 
Signed-off-by: David S. Miller