On 08/27, Jiri Olsa wrote:
>
> did you just bpftrace-ed bpftrace? ;-) on my setup I'm getting:
>
> [root@qemu ex]# ../bpftrace/build/src/bpftrace -e 'kprobe:uprobe_register { printf("%s\n", kstack); }'
> Attaching 1 probe...
>
> uprobe_register+1
so I guess you are on tip/perf/core which killed uprobe_register_refctr()
and changed bpf_uprobe_multi_link_attach() to use uprobe_register
> bpf_uprobe_multi_link_attach+685
> __sys_bpf+9395
> __x64_sys_bpf+26
> do_syscall_64+128
> entry_SYSCALL_64_after_hwframe+118
>
>
> I'm not sure what's bpftrace version in fedora 40, I'm using upstream build:
bpftrace v0.20.1
> [root@qemu ex]# ../bpftrace/build/src/bpftrace --info 2>&1 | grep uprobe_multi
> uprobe_multi: yes
Aha, I get
uprobe_multi: no
OK. So, on your setup bpftrace uses bpf_uprobe_multi_link_attach()
and this implies ->ret_handler = uprobe_multi_link_ret_handler()
which calls uprobe_prog_run() which does
if (link->task && current->mm != link->task->mm)
return 0;
So, can you reproduce the problem reported by Tianyi on your setup?
Oleg.
