From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Jianlin Lv <Jianlin.Lv@arm.com>
Cc: bpf <bpf@vger.kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Yonghong Song <yhs@fb.com>,
open list <linux-kernel@vger.kernel.org>,
Networking <netdev@vger.kernel.org>
Subject: Re: [PATCH bpf-next v2] bpf: fix segmentation fault of test_progs
Date: Mon, 10 Aug 2020 17:23:59 -0700 [thread overview]
Message-ID: <CAEf4BzbYFDBXNwE-3B4vc6oZvbDbSTbwf4xgUeUpkwJ2FCQY+w@mail.gmail.com> (raw)
In-Reply-To: <20200810153940.125508-1-Jianlin.Lv@arm.com>
On Mon, Aug 10, 2020 at 8:40 AM Jianlin Lv <Jianlin.Lv@arm.com> wrote:
>
> test_progs reports the segmentation fault as below
>
> $ sudo ./test_progs -t mmap --verbose
> test_mmap:PASS:skel_open_and_load 0 nsec
> ......
> test_mmap:PASS:adv_mmap1 0 nsec
> test_mmap:PASS:adv_mmap2 0 nsec
> test_mmap:PASS:adv_mmap3 0 nsec
> test_mmap:PASS:adv_mmap4 0 nsec
> Segmentation fault
>
> This issue was triggered because mmap() and munmap() used inconsistent
> length parameters; mmap() creates a new mapping of 3*page_size, but the
> length parameter set in the subsequent re-map and munmap() functions is
> 4*page_size; this leads to the destruction of the process space.
>
> To fix this issue, first create 4 pages of anonymous mapping,then do all
> the mmap() with MAP_FIXED.
>
> Another issue is that when unmap the second page fails, the length
> parameter to delete tmp1 mappings should be 4*page_size.
>
> Signed-off-by: Jianlin Lv <Jianlin.Lv@arm.com>
> ---
LGTM, thanks for the fix!
Acked-by: Andrii Nakryiko <andriin@fb.com>
> v2:
> - Update commit messages
> - Create 4 pages of anonymous mapping that serve the subsequent mmap()
> ---
> tools/testing/selftests/bpf/prog_tests/mmap.c | 19 +++++++++++++------
> 1 file changed, 13 insertions(+), 6 deletions(-)
>
[...]
next prev parent reply other threads:[~2020-08-11 0:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-31 6:16 [PATCH bpf-next] bpf: fix compilation warning of selftests Jianlin Lv
2020-07-31 15:00 ` Daniel Borkmann
2020-07-31 17:39 ` Andrii Nakryiko
2020-08-06 10:42 ` [PATCH bpf-next v2] " Jianlin Lv
2020-08-07 0:05 ` Alexei Starovoitov
2020-08-07 17:20 ` [PATCH bpf-next] bpf: fix segmentation fault of test_progs Jianlin Lv
2020-08-07 20:13 ` Andrii Nakryiko
2020-08-10 15:39 ` [PATCH bpf-next v2] " Jianlin Lv
2020-08-11 0:23 ` Andrii Nakryiko [this message]
2020-08-11 13:19 ` Daniel Borkmann
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