This is a note to let you know that I've just added the patch titled powerpc/xmon: Fix data-breakpoint to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-xmon-fix-data-breakpoint.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From c21a493a2b44650707d06741601894329486f2ad Mon Sep 17 00:00:00 2001 From: Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxxxxxxx> Date: Tue, 22 Nov 2016 14:55:59 +0530 Subject: powerpc/xmon: Fix data-breakpoint From: Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/powerpc/kernel/hw_breakpoint.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -228,8 +228,10 @@ int hw_breakpoint_handler(struct die_arg rcu_read_lock(); bp = __this_cpu_read(bp_per_reg); - if (!bp) + if (!bp) { + rc = NOTIFY_DONE; goto out; + } info = counter_arch_bp(bp); /* Patches currently in stable-queue which might be from ravi.bangoria@xxxxxxxxxxxxxxxxxx are queue-4.9/powerpc-xmon-fix-data-breakpoint.patch