Messages in this thread | | | From | Jiri Olsa <> | Date | Sun, 28 May 2023 22:02:49 +0200 | Subject | Re: [RFC PATCH stable 5.4 0/8] bpf: Fix bpf_probe_read/bpf_probe_read_str helpers |
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On Fri, May 26, 2023 at 07:54:17PM +0100, Greg KH wrote: > On Mon, May 22, 2023 at 10:33:44PM +0200, Jiri Olsa wrote: > > hi, > > we see broken access to user space with bpf_probe_read/bpf_probe_read_str > > helpers on arm64 with 5.4 kernel. The problem is that both helpers try to > > read user memory by calling probe_kernel_read, which seems to work on x86 > > but fails on arm64. > > Has this ever worked on arm64 for the 5.4 kernel tree? If not, it's not > really a regression, and so, why not use a newer kernel that has this > new feature added to it there? > > In other words, what requires you to use the 5.4.y tree and requires > feature parity across architectures?
we have a customer running ok on x86 v5.4, but arm64 is broken with the same bpf/user space code
upgrade is an option of course, but it's not a big change and we can have 5.4 working on arm64 as well
I can send out the change that will be closer to upstream changes, if that's a concern.. with adding the new probe helpers, which I guess is not a problem, because it does not change current API
jirka
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