From mboxrd@z Thu Jan 1 00:00:00 1970 From: srikar@linux.vnet.ibm.com (Srikar Dronamraju) Date: Wed, 4 Jul 2018 02:16:52 -0700 Subject: [PATCH v5 06/10] Uprobes: Support SDT markers having reference count (semaphore) In-Reply-To: References: <20180628052209.13056-1-ravi.bangoria@linux.ibm.com> <20180628052209.13056-7-ravi.bangoria@linux.ibm.com> <20180701210935.GA14404@redhat.com> <0c543791-f3b7-5a4b-f002-e1c76bb430c0@linux.ibm.com> <20180702180156.GA31400@redhat.com> <20180703061612.GG65296@linux.vnet.ibm.com> Message-ID: <20180704091652.GA21902@linux.vnet.ibm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org > > I'm not sure if I get your concerns but let me try to explain what happens > in such cases. please let me know if I misunderstood your point. > > 1. Install a probe using perf. > # ./perf probe sdt_tick:loop2 > > > > Does this explain your concerns? > No, this was not my concern. My concern is with two users on the same USDT. 1. First user enables the probe point but doesn't increment the ref_cnt. via uprobe_register 2. Second user tries to enable the probe point and also increments the ref_cnt via uprobe_register_refctr. 3. If the second user now removes the probe point via uprobe_unregister. 4. What is the state of the ref_cnt? -- Thanks and Regards Srikar