Re: [PATCH v2 3/3] tracing/kprobes: Use APIs that matches symbols without .XXX suffix
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2024-08-06 20:00:03
Also in:
live-patching, lkml
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2024-08-06 20:00:03
Also in:
live-patching, lkml
On Tue, 6 Aug 2024 19:35:07 +0000 Song Liu [off-list ref] wrote:
quoted
quoted
+ if (IS_ENABLED(CONFIG_LTO_CLANG) && !addr) + addr = kallsyms_lookup_name_without_suffix(trace_kprobe_symbol(tk)); +So you do the lookup twice if this is enabled? Why not just use "kallsyms_lookup_name_without_suffix()" the entire time, and it should work just the same as "kallsyms_lookup_name()" if it's not needed?We still want to give priority to full match. For example, we have: [root@~]# grep c_next /proc/kallsyms ffffffff81419dc0 t c_next.llvm.7567888411731313343 ffffffff81680600 t c_next ffffffff81854380 t c_next.llvm.14337844803752139461 If the goal is to explicitly trace c_next.llvm.7567888411731313343, the user can provide the full name. If we always match _without_suffix, all of the 3 will match to the first one. Does this make sense?
Yes. Sorry, I missed the "&& !addr)" after the "IS_ENABLED()", which looked like you did the command twice. I blame jetlag ;-) -- Steve