Date: Thu, 12 Sep 2019 14:23:14 +0530 From: shreyank amartya <shreyankfbsd@gmail.com> To: Navdeep Parhar <nparhar@gmail.com> Cc: freebsd-drivers@freebsd.org, freebsd-hackers@freebsd.org Subject: Re: hwpmc ktrdump: failed to resolve ktr symbols Message-ID: <CAD9jf8DwYRr1gBKF2u8MSxrWdv9GZTs-CDO=Pfp9xMPAEkBbdw@mail.gmail.com> In-Reply-To: <0534e1a9-af57-96cf-9ea2-ec4b30021226@gmail.com> References: <CAD9jf8BXm2PgY=5DkKxrweuG4x-QEERhJyPTESCkxt_Bi84E9Q@mail.gmail.com> <0534e1a9-af57-96cf-9ea2-ec4b30021226@gmail.com>
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Thanks, yes it seems I was missing both those options (KTR and DDB) in my kernel config. Now, I have a module (hwpmc) from which I intend to collect traces. However, when I build and load it, I don't see any ktraces when using it. But if I install it and load the module on boot, ktraces appear. Why does that happen? Anyway around that? Thanks Shreyank On Fri, Aug 30, 2019 at 9:37 PM Navdeep Parhar <nparhar@gmail.com> wrote: > On 2019-08-30 03:54, shreyank amartya wrote: > > Hi, > > > > I'm trying to collect traces from hwpmc module. I compiled the module > with > > -DHWPMC_DEBUG option and set the sysctl kern.hwpmc.debugflags but I'm > > unable to retrive the traces using ktrdump. I get this error message: > > > > ktrdump: failed to resolve ktr symbols > > > > I'm guessing that this error occurs because the symbols for hwpmc module > > (compiled and loaded separately) are not a part of kernel. If this is the > > case, then how do I get those symbols. In the ktr man page its also > > mentioned that ddb and gdb can retrieve ktraces. > > > > I found the ddb command show ktr. But how do I invoke ddb (without a > panic)? > > sysctl debug.kdb.enter=1 > > > > > I'm unable to find how can I use gdb to view the traces (I launched kgdb > > but could not find a command to show kernel traces). > > > > Any idea on how to get ktrdump working? Or get the kernel traces. > > You need a kernel with KTR support. See ktr(4) for a full list of > the options and other details. See "sysctl kern.conftxt" for what's > in your running kernel. > > Regards, > Navdeep >
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