| From | Willy Tarreau <> | Subject | [PATCH 3.10 163/268] powerpc/xmon: Fix data-breakpoint | Date | Mon, 19 Jun 2017 20:31:02 +0200 |
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From: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
commit c21a493a2b44650707d06741601894329486f2ad upstream.
Currently xmon data-breakpoint feature is broken.
Whenever there is a watchpoint match occurs, hw_breakpoint_handler will be called by do_break via notifier chains mechanism. If watchpoint is registered by xmon, hw_breakpoint_handler won't find any associated perf_event and returns immediately with NOTIFY_STOP. Similarly, do_break also returns without notifying to xmon.
Solve this by returning NOTIFY_DONE when hw_breakpoint_handler does not find any perf_event associated with matched watchpoint, rather than NOTIFY_STOP, which tells the core code to continue calling the other breakpoint handlers including the xmon one.
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Willy Tarreau <w@1wt.eu> --- arch/powerpc/kernel/hw_breakpoint.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c index f0b47d1..7531f9a 100644 --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -228,8 +228,10 @@ int __kprobes hw_breakpoint_handler(struct die_args *args) rcu_read_lock(); bp = __get_cpu_var(bp_per_reg); - if (!bp) + if (!bp) { + rc = NOTIFY_DONE; goto out; + } info = counter_arch_bp(bp); /* -- 2.8.0.rc2.1.gbe9624a
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