From: "Toke Høiland-Jørgensen" <toke@redhat•com>
To: kernel test robot <rong.a.chen@intel•com>
Cc: "David Miller" <davem@davemloft•net>,
netdev@vger•kernel.org,
"Jesper Dangaard Brouer" <brouer@redhat•com>,
"Daniel Borkmann" <daniel@iogearbox•net>,
"Alexei Starovoitov" <ast@kernel•org>,
"Jakub Kicinski" <jakub.kicinski@netronome•com>,
BjörnTöpel <bjorn.topel@gmail•com>,
lkp@01•org
Subject: Re: [xdp] 9cb54e254c: kernel/bpf/devmap.c:#suspicious_rcu_dereference_check()
Date: Wed, 10 Apr 2019 12:00:58 +0200 [thread overview]
Message-ID: <87r2aaw55x.fsf@toke.dk> (raw)
In-Reply-To: <20190410075954.GC17122@shao2-debian>
kernel test robot <rong.a.chen@intel•com> writes:
> FYI, we noticed the following commit (built with gcc-7):
>
> commit: 9cb54e254ca479ce636857a1fd1e1a3e9f8796b1 ("[PATCH net-next v4 4/6] xdp: Always use a devmap for XDP_REDIRECT to a device")
> url: https://github.com/0day-ci/linux/commits/Toke-H-iland-J-rgensen/xdp-Use-a-default-map-for-xdp_redirect-helper/20190409-161851
>
>
> in testcase: trinity
> with following parameters:
>
> runtime: 300s
>
> test-description: Trinity is a linux system call fuzz tester.
> test-url: http://codemonkey.org.uk/projects/trinity/
>
>
> on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 8G
>
> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
>
>
> +--------------------------------------------------------------+------------+------------+
> | | c76c665440 | 9cb54e254c |
> +--------------------------------------------------------------+------------+------------+
> | boot_successes | 0 | 0 |
> | boot_failures | 40 | 38 |
> | BUG:kernel_reboot-without-warning_in_test_stage | 28 | 10 |
> | BUG:kernel_hang_in_boot_stage | 12 | 12 |
> | WARNING:suspicious_RCU_usage | 0 | 16 |
> | kernel/bpf/devmap.c:#suspicious_rcu_dereference_check()usage | 0 | 16 |
> +--------------------------------------------------------------+------------+------------+
>
>
>
> [ 413.653218] WARNING: suspicious RCU usage
> [ 413.654564] 5.1.0-rc4-00599-g9cb54e2 #43 Tainted: G T
> [ 413.656563] -----------------------------
> [ 413.657808] kernel/bpf/devmap.c:807 suspicious rcu_dereference_check() usage!
> [ 413.660285]
> [ 413.660285] other info that might help us debug this:
> [ 413.660285]
> [ 413.662614]
> [ 413.662614] rcu_scheduler_active = 2, debug_locks = 1
> [ 413.664483] 2 locks held by trinity-c3/2248:
> [ 413.665800] #0: 00000000713e8e50 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x81/0x90
> [ 413.668184] #1: 000000005e54a26c (&p->lock){+.+.}, at: seq_lseek+0x42/0x1c0
> [ 413.670412]
> [ 413.670412] stack backtrace:
> [ 413.671876] CPU: 0 PID: 2248 Comm: trinity-c3 Tainted: G T 5.1.0-rc4-00599-g9cb54e2 #43
> [ 413.674557] Call Trace:
> [ 413.675374] dump_stack+0x1e/0x28
> [ 413.676366] lockdep_rcu_suspicious+0xc6/0xd0
> [ 413.677802] dev_map_default_show+0x84/0xd0
Ah, right, seems I forgot an rcu_read_lock() here. Will fix :)
-Toke
next prev parent reply other threads:[~2019-04-10 10:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-08 17:05 [PATCH net-next v4 0/6] xdp: Use a default map for xdp_redirect helper Toke Høiland-Jørgensen
2019-04-08 17:05 ` [PATCH net-next v4 5/6] xdp: Add devmap_idx map type for looking up devices by ifindex Toke Høiland-Jørgensen
2019-04-08 17:05 ` [PATCH net-next v4 3/6] xdp: Refactor devmap code in preparation for subsequent additions Toke Høiland-Jørgensen
2019-04-08 17:05 ` [PATCH net-next v4 1/6] net: xdp: refactor XDP attach Toke Høiland-Jørgensen
2019-04-08 20:23 ` Daniel Borkmann
2019-05-09 10:40 ` Björn Töpel
2019-04-09 12:54 ` kbuild test robot
2019-04-08 17:05 ` [PATCH net-next v4 2/6] net: xdp: remove XDP_QUERY_PROG Toke Høiland-Jørgensen
2019-04-08 17:05 ` [PATCH net-next v4 4/6] xdp: Always use a devmap for XDP_REDIRECT to a device Toke Høiland-Jørgensen
2019-04-09 8:25 ` Jesper Dangaard Brouer
2019-04-09 9:23 ` Toke Høiland-Jørgensen
2019-04-10 7:59 ` [xdp] 9cb54e254c: kernel/bpf/devmap.c:#suspicious_rcu_dereference_check() kernel test robot
2019-04-10 10:00 ` Toke Høiland-Jørgensen [this message]
2019-04-08 17:05 ` [PATCH net-next v4 6/6] selftests/bpf: Add test for default devmap allocation Toke Høiland-Jørgensen
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