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charset="UTF-8" X-Rspamd-Queue-Id: BB851B0081FC X-Stat-Signature: aeegyoi9oywbaym75ux7bnqg5orjkc87 Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=cLxEFDVZ; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf24.hostedemail.com: domain of laoar.shao@gmail.com designates 209.85.160.170 as permitted sender) smtp.mailfrom=laoar.shao@gmail.com X-Rspamd-Server: rspam02 X-HE-Tag: 1638199768-515105 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Nov 29, 2021 at 10:21 PM Sven Schnelle wrote: > > Hi, > > Yafang Shao writes: > > > On Mon, Nov 29, 2021 at 6:13 PM Sven Schnelle wrote: > >> > diff --git a/include/linux/sched.h b/include/linux/sched.h > >> > index 78c351e35fec..cecd4806edc6 100644 > >> > --- a/include/linux/sched.h > >> > +++ b/include/linux/sched.h > >> > @@ -274,8 +274,13 @@ struct task_group; > >> > > >> > #define get_current_state() READ_ONCE(current->__state) > >> > > >> > -/* Task command name length: */ > >> > -#define TASK_COMM_LEN 16 > >> > +/* > >> > + * Define the task command name length as enum, then it can be visible to > >> > + * BPF programs. > >> > + */ > >> > +enum { > >> > + TASK_COMM_LEN = 16, > >> > +}; > >> > >> This breaks the trigger-field-variable-support.tc from the ftrace test > >> suite at least on s390: > >> > >> echo > >> 'hist:keys=next_comm:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,sched.sched_waking.prio,next_comm) > >> if next_comm=="ping"' > >> linux/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-field-variable-support.tc: line 15: echo: write error: Invalid argument > >> > >> I added a debugging line into check_synth_field(): > >> > >> [ 44.091037] field->size 16, hist_field->size 16, field->is_signed 1, hist_field->is_signed 0 > >> > >> Note the difference in the signed field. > >> > > > > Hi Sven, > > > > Thanks for the report and debugging! > > Seems we should explicitly define it as signed ? > > Could you pls. help verify it? > > > > diff --git a/include/linux/sched.h b/include/linux/sched.h > > index cecd4806edc6..44d36c6af3e1 100644 > > --- a/include/linux/sched.h > > +++ b/include/linux/sched.h > > @@ -278,7 +278,7 @@ struct task_group; > > * Define the task command name length as enum, then it can be visible to > > * BPF programs. > > */ > > -enum { > > +enum SignedEnum { > > TASK_COMM_LEN = 16, > > }; > > Umm no. What you're doing here is to define the name of the enum as > 'SignedEnum'. This doesn't change the type. I think before C++0x you > couldn't force an enum type. > Ah, I made a stupid mistake.... -- Thanks Yafang