Re: [PATCH bpf-next 4/9] uprobes/x86: Don't WARN if an optimized probe can't be written

[sashiko-bot@kernel.org]

> From: Alexei Starovoitov <ast@kernel.org>
> 
> __arch_uprobe_optimize() and set_orig_insn() do WARN_ON_ONCE() when
> uprobe_write() fails, and user space can make it fail:
> - -EINTR from get_user_pages_remote() when current is being killed.
> - -ENOMEM when COW can't be broken, since memcg is at its limit.
> - -EINVAL from __update_ref_ctr() when the process cleared the semaphore
>   of SDT probe.
> 
> Kill the processes that call probed nop10. It warns in 8 of 8 runs:
> 
>   WARNING: arch/x86/kernel/uprobes.c:1186 at arch_uprobe_optimize+0x291/0x3a0
>    uprobe_notify_resume+0x1c3/0x4c0
>    exit_to_user_mode_loop+0x63/0x4e0
>    exc_int3+0x1f3/0x250
> [ ... ]
> 
> This depends on the previous patch. Without it WARN was the only sign of
> the bytes that set_orig_insn() cannot restore. Hence no Fixes tag.
> 
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261022015712.1297331-1-alexei.starovoitov@gmail.com?part=4