On Tue, 23 Feb 2021 00:05:08 +0900 Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote: > Hi Evgenii, > > On Thu, 18 Feb 2021 20:09:17 +0300 > Evgenii Shatokhin <eshatokhin@xxxxxxxxxxxxx> wrote: > > > Hi, > > > > It seems, 'perf probe' can only see functions from .text section in the > > kernel modules, but not from .text.unlikely or other .text.* sections. > > > > For example, with kernel 5.11 and nf_conntrack.ko with debug info, 'perf > > probe' succeeds for nf_conntrack_attach() from .text and fails for > > nf_ct_resolve_clash() from .text.unlikely: > > Thanks for reporting it! > > > > > ------------ > > # perf probe -v -m nf_conntrack nf_ct_resolve_clash > > probe-definition(0): nf_ct_resolve_clash > > symbol:nf_ct_resolve_clash file:(null) line:0 offset:0 return:0 lazy:(null) > > 0 arguments > > Failed to get build-id from nf_conntrack. > > Cache open error: -1 > > Open Debuginfo file: > > /lib/modules/5.11.0-test01/kernel/net/netfilter/nf_conntrack.ko > > Try to find probe point from debuginfo. > > Matched function: nf_ct_resolve_clash [33616] > > Probe point found: nf_ct_resolve_clash+0 > > Found 1 probe_trace_events. > > Post processing failed or all events are skipped. (-2) > > Probe point 'nf_ct_resolve_clash' not found. > > Error: Failed to add events. Reason: No such file or directory (Code: -2) > [...] > > Is there a way to allow probing of functions in .text.<something> ? BTW, just for putting a probe on nf_ct_resolve_clash, please give the module *path* instead of the module *name*. For example, perf probe -v -m /lib/modules/5.11.0-test01/kernel/net/netfilter/nf_conntrack.ko nf_ct_resolve_clash This should work (at least works for me), because it directly loads the symbols from the .ko file. Thank you, -- Masami Hiramatsu <mhiramat@xxxxxxxxxx>
