linux-toradex.git/kernel/events/hw_breakpoint.c, branch v3.0.95 Linux kernel for Apalis and Colibri modules hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot() 2013-07-03T18:03:23+00:00 Oleg Nesterov oleg@redhat.com 2013-06-20T15:50:09+00:00 e2652ea43028e5409c2fd2b585dc8388a6e75bd0 commit c790b0ad23f427c7522ffed264706238c57c007e upstream. fetch_bp_busy_slots() and toggle_bp_slot() use for_each_online_cpu(), this is obviously wrong wrt cpu_up() or cpu_down(), we can over/under account the per-cpu numbers. For example: # echo 0 >> /sys/devices/system/cpu/cpu1/online # perf record -e mem:0x10 -p 1 & # echo 1 >> /sys/devices/system/cpu/cpu1/online # perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10 -C1 -a & # taskset -p 0x2 1 triggers the same WARN_ONCE("Can't find any breakpoint slot") in arch_install_hw_breakpoint(). Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20130620155009.GA6327@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c790b0ad23f427c7522ffed264706238c57c007e upstream.

fetch_bp_busy_slots() and toggle_bp_slot() use
for_each_online_cpu(), this is obviously wrong wrt cpu_up() or
cpu_down(), we can over/under account the per-cpu numbers.

For example:

	# echo 0 >> /sys/devices/system/cpu/cpu1/online
	# perf record -e mem:0x10 -p 1 &
	# echo 1 >> /sys/devices/system/cpu/cpu1/online
	# perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10 -C1 -a &
	# taskset -p 0x2 1

triggers the same WARN_ONCE("Can't find any breakpoint slot") in
arch_install_hw_breakpoint().

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155009.GA6327@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hw breakpoints: Move to kernel/events/ 2011-05-03T13:26:43+00:00 Borislav Petkov borislav.petkov@amd.com 2011-05-03T13:26:43+00:00 48dbb6dc86ca5d1b2224937d774c7ba98bc3a485 As part of the events sybsystem unification, relocate hw_breakpoint.c into its new destination. Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> 
As part of the events sybsystem unification, relocate hw_breakpoint.c
into its new destination.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>