From mboxrd@z Thu Jan 1 00:00:00 1970 From: ravi.bangoria@linux.ibm.com (Ravi Bangoria) Date: Mon, 13 Aug 2018 19:56:53 +0530 Subject: [PATCH v8 3/6] Uprobes: Support SDT markers having reference count (semaphore) In-Reply-To: <20180813131723.GC28360@redhat.com> References: <20180809041856.1547-1-ravi.bangoria@linux.ibm.com> <20180809041856.1547-4-ravi.bangoria@linux.ibm.com> <95a1221e-aecc-42be-5239-a2c2429be176@linux.ibm.com> <20180813115019.GB28360@redhat.com> <20180813131723.GC28360@redhat.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 08/13/2018 06:47 PM, Oleg Nesterov wrote: > On 08/13, Ravi Bangoria wrote: >> >>> But damn, process creation (exec) is trivial. We could add a new uprobe_exec() >>> hook and avoid delayed_uprobe_install() in uprobe_mmap(). >> >> I'm sorry. I didn't get this. > > Sorry for confusion... > > I meant, if only exec*( could race with _register(), we could add another uprobe > hook which updates all (delayed) counters before return to user-mode. Ok. > >>> Afaics, the really problematic case is dlopen() which can race with _register() >>> too, right? >> >> dlopen() should internally use mmap() right? So what is the problem here? Can >> you please elaborate. > > What I tried to say is that we can't avoid uprobe_mmap()->delayed_uprobe_install() > because dlopen() can race with _register() too, just like exec. Right :) Thanks, Ravi