On Tue, 19 Jul 2022, 2:40pm, Steven Rostedt wrote: > On Tue, 19 Jul 2022 14:06:11 -0700 > Arun Easi <aeasi@xxxxxxxxxxx> wrote: > > > It appears by calling the above two interfaces, I get a separate instance > > of "qla" only traces, but with only the "qla"-only instance being enabled, > > leaving the main (/sys/kernel/tracing/events/qla/enable) one disabled. No > > issues there, but when I enable both of them, I get garbage values on one. > > > > /sys/kernel/tracing/instances/qla2xxx/trace: > > cat-56106 [012] ..... 2419873.470098: ql_dbg_log: qla2xxx [0000:05:00.0]-1054:14: Entered (null). > > cat-56106 [012] ..... 2419873.470101: ql_dbg_log: qla2xxx [0000:05:00.0]-1000:14: Entered ×+<96>²Ü<98>^H. > > cat-56106 [012] ..... 2419873.470102: ql_dbg_log: qla2xxx [0000:05:00.0]-1006:14: Prepare to issue mbox cmd=0xde589000. > > > > /sys/kernel/tracing/trace: > > cat-56106 [012] ..... 2419873.470097: ql_dbg_log: qla2xxx [0000:05:00.0]-1054:14: Entered qla2x00_get_firmware_state. > > cat-56106 [012] ..... 2419873.470100: ql_dbg_log: qla2xxx [0000:05:00.0]-1000:14: Entered qla2x00_mailbox_command. > > cat-56106 [012] ..... 2419873.470102: ql_dbg_log: qla2xxx [0000:05:00.0]-1006:14: Prepare to issue mbox cmd=0x69. > > > > It appears that only one should be enabled at a time. Per my read of > > Documentation/trace/ftrace.rst, the main directory and instances have > > separate trace buffers, so I am a bit confused with the above output. > > That's because it uses va_list, and va_list can only be used once. Ah, that makes sense. > > I just added helpers for va_list use cases: > > https://urldefense.proofpoint.com/v2/url?u=https-3A__lore.kernel.org_all_20220705224453.120955146-40goodmis.org_&d=DwIFaQ&c=nKjWec2b6R0mOyPaz7xtfQ&r=P-q_Qkt75qFy33SvdD2nAxAyN87eO1d-mFO-lqNOomw&m=cDBXba_lNDGk7c1Qm4elDe1Co-RV8zR-c1A9xV7vc4nMcQO7iRle72qNxljHsDNA&s=74PzgMj6nmfRCLXd3oMIqt-_DZbQeukUl0nK7MzfUjs&e= > > But it will likely suffer the same issue, but I can easily fix that with > this on top: > > Not even compiled tested: > > -- Steve > > diff --git a/include/trace/stages/stage6_event_callback.h b/include/trace/stages/stage6_event_callback.h > index 0f51f6b3ab70..3c554a585320 100644 > --- a/include/trace/stages/stage6_event_callback.h > +++ b/include/trace/stages/stage6_event_callback.h > @@ -40,7 +40,12 @@ > > #undef __assign_vstr > #define __assign_vstr(dst, fmt, va) \ > - vsnprintf(__get_str(dst), TRACE_EVENT_STR_MAX, fmt, *(va)) > + do { \ > + va_list __cp_va; \ > + va_copy(__cp_va, *(va)); \ > + vsnprintf(__get_str(dst), TRACE_EVENT_STR_MAX, fmt, __cp_va); \ > + va_end(__cp_va); \ > + } while (0) > > #undef __bitmask > #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1) > This will be nice. Thanks for your help, Steve. Regards, -Arun
