powerpc/hw_breakpoints: Fix incorrect pointer access

If arch_validate_hwbkpt_settings() fails, bp->ctx won't be valid and the
kernel panics. Add a check to fix this.

Reported-by: Edjunior Barbosa Machado <emachado@linux.vnet.ibm.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Naveen N. Rao 2012-07-06 01:30:58 +00:00 committed by Benjamin Herrenschmidt
parent 1d5a436d2c
commit ac84aa2b3b

View file

@ -111,7 +111,7 @@ void arch_unregister_hw_breakpoint(struct perf_event *bp)
* and the single_step_dabr_instruction(), then cleanup the breakpoint
* restoration variables to prevent dangling pointers.
*/
if (bp->ctx->task)
if (bp->ctx && bp->ctx->task)
bp->ctx->task->thread.last_hit_ubp = NULL;
}