Re: uprobe splat in PREEMP_RT

Steven Rostedt
2025-04-01T21:21:25Z

On Tue, 1 Apr 2025 14:04:22 -0700
Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:

> Looks like write_seqcount_begin(&utask->ri_seqcount);
> use in ri_timer() needs a fix ?

Hmm,

write_seqcount_begin(&utask->ri_seqcount);

for_each_ret_instance_rcu(ri, utask->return_instances)
hprobe_expire(&ri->hprobe, false);

write_seqcount_end(&utask->ri_seqcount);

How big can that loop be?

Of course, we could just say not to use uprobes on PREEMPT_RT kernels?
Otherwise, they could cause an unspecified latency.

-- Steve