From: Sumanth Korikkar <sumanthk@linux.ibm.com>
To: jolsa@redhat.com
Cc: Sumanth.Korikkar@ibm.com, sumanthk@linux.ibm.com,
agordeev@linux.ibm.com, ast@kernel.org, bas@baslab.org,
bpf@vger.kernel.org, brendan.d.gregg@gmail.com,
daniel@iogearbox.net, dxu@dxuuu.xyz, linux-s390@vger.kernel.org,
mat@mmarchini.me, netdev@vger.kernel.org,
yauheni.kaliuta@redhat.com
Subject: Re: bpf: bpf_probe_read helper restriction on s390x
Date: Mon, 6 Jul 2020 10:54:56 +0200 [thread overview]
Message-ID: <20200706085456.48306-1-sumanthk@linux.ibm.com> (raw)
In-Reply-To: <20200705194225.GB3356590@krava>
Hi Jiri,
Sorry about the noise. My email seems to be rejected to the list. Resending
with plain text.
s390 has overlapping address space. As suggested by the commit,
ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE should not be enabled for s390 kernel.
This should be changed in bpftrace application.
Even if we enable ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE, bpf_probe_read will
only work in certain cases like kernel pointer deferences (kprobes). User
pointer deferences in uprobes/kprobes/etc will fail or have some invalid data
I am looking forward to this fix: https://github.com/iovisor/bpftrace/pull/1141
OR probe split in bpftrace.
Thank you
Best Regards
Sumanth
next prev parent reply other threads:[~2020-07-06 8:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-05 19:42 bpf: bpf_probe_read helper restriction on s390x Jiri Olsa
2020-07-06 8:54 ` Sumanth Korikkar [this message]
[not found] <OFDA9C9258.BBAFD274-ON0025859D.001E3F9D-C125859D.001E497A@notes.na.collabserv.com>
[not found] ` <f95739ee-59a9-4dfc-8da0-dfef2c73bd6a@linux.ibm.com>
2020-07-06 10:15 ` Jiri Olsa
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