On Fri, Apr 22, 2011 at 03:16:27PM +0200, Frederic Weisbecker wrote: > (resend with ppc list in cc) > > While the tracer accesses ptrace breakpoints, the child task may > concurrently exit due to a SIGKILL and thus release its breakpoints > at the same time. We can then dereference some freed pointers. > > To fix this, hold a reference on the child breakpoints before > manipulating them. > > Reported-by: Oleg Nesterov <o...@redhat.com> > Signed-off-by: Frederic Weisbecker <fweis...@gmail.com> > Cc: Ingo Molnar <mi...@elte.hu> > Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org> > Cc: Peter Zijlstra <a.p.zijls...@chello.nl> > Cc: Will Deacon <will.dea...@arm.com> > Cc: Prasad <pra...@linux.vnet.ibm.com> > Cc: Paul Mundt <let...@linux-sh.org> > Cc: v2.6.33.. <sta...@kernel.org> > --- > arch/powerpc/kernel/ptrace.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c > index 55613e3..4edeeb3 100644 > --- a/arch/powerpc/kernel/ptrace.c > +++ b/arch/powerpc/kernel/ptrace.c > @@ -1591,7 +1591,10 @@ long arch_ptrace(struct task_struct *child, long > request, > } > > case PTRACE_SET_DEBUGREG: > + if (ptrace_get_breakpoints(child) < 0) > + return -ESRCH; > ret = ptrace_set_debugreg(child, addr, data); > + ptrace_put_breakpoints(child); > break; > > #ifdef CONFIG_PPC64 > -- > 1.7.3.2 >
Hi Frederic, Looks fine to me. Acked-by: K.Prasad <pra...@linux.vnet.ibm.com> Thanks, K.Prasad _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev