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H A D | hw_breakpoint.c | diff bc01bdf6c5df5023272a7399962cf64f8fedc93e Tue Sep 10 15:15:13 CEST 2019 Ravi Bangoria <ravi.bangoria@linux.ibm.com> powerpc/watchpoint: Disable watchpoint hit by larx/stcx instructions
If watchpoint exception is generated by larx/stcx instructions, the reservation created by larx gets lost while handling exception, and thus stcx instruction always fails. Generally these instructions are used in a while(1) loop, for example spinlocks. And because stcx never succeeds, it loops forever and ultimately hangs the system.
Note that ptrace anyway works in one-shot mode and thus for ptrace we don't change the behaviour. It's up to ptrace user to take care of this.
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190910131513.30499-1-ravi.bangoria@linux.ibm.com
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