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From: "me at serhei dot io" <sourceware-bugzilla@sourceware.org>
To: systemtap@sourceware.org
Subject: [Bug kprobes/26755] New: recent rawhide: grabbing several lock:lock_* tracepoints leads to hard lockup?
Date: Mon, 19 Oct 2020 19:54:46 +0000	[thread overview]
Message-ID: <bug-26755-6586@http.sourceware.org/bugzilla/> (raw)

https://sourceware.org/bugzilla/show_bug.cgi?id=26755

            Bug ID: 26755
           Summary: recent rawhide: grabbing several lock:lock_*
                    tracepoints leads to hard lockup?
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: kprobes
          Assignee: systemtap at sourceware dot org
          Reporter: me at serhei dot io
  Target Milestone: ---

Started seeing this on the rawhide buildbot with kprobes_onthefly.exp (which
probes all possible tracepoints in the 'hardcore' case). On a lockdep enabled
kernel this grabs lock:lock_{acquire,acquired,release,contended}.

The tricky part is that the hard lockup only happens if more than one of these
tracepoints is probed.

For now I'm disabling those tracepoints in the testcase (similar to hcall_*
blacklist on ppc) but we need to figure out if something/anything needs to be
blacklisted for recent kernels.

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             reply	other threads:[~2020-10-19 19:54 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-19 19:54 me at serhei dot io [this message]
2020-10-20 15:57 ` [Bug kprobes/26755] recent rawhide: grabbing several lock:lock_* tracepoints leads to hard lockup in kprobes_onthefly me at serhei dot io

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