powerpc: fork && stepping (Was: [RFC,PATCH 0/14] utrace/ptrace)
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From: Ananth N Mavinakayanahalli on 28 Nov 2009 02:10 On Fri, Nov 27, 2009 at 04:05:31PM +0100, Oleg Nesterov wrote: > On 11/27, Ananth N Mavinakayanahalli wrote: > > > > On Thu, Nov 26, 2009 at 03:50:51PM +0100, Oleg Nesterov wrote: > > > > > Ananth, could you please run the test-case from the changelog > > > below ? I do not really expect this can help, but just in case. > > > > Right, it doesn't help :-( > > > > GDB shows that the parent is forever struck at wait(). > > Now this is interesting. Could you please double check the parent hangs > in wait() ? > > This doesn't match the testing we did on powerpc machine with Veaceslav, > and I hoped the problem was already resolved? > > Please see other emails in this thread. > > > Hmm. Fortunately I still have the access to the testing machine. > Yes, according to gdb it looks as if it "hangs" in wait(). This > is not true. You can strace gdb itself, or look at xxx_ctxt_switches > in /proc/pid_of_parent/status. > > Better yet, do not use gdb at all. Just strace (without -f) the parent, > you should see it continues to trace the child and loops forever. Yes, I can see it looping. However, Veaceslav's modified testcase in http://lkml.org/lkml/2009/11/27/215 passes on the machine with ptrace-copy_process-should-disable-stepping.patch. Ananth -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |