perf/x86/intel/bts: Fix DS area sharing with x86_pmu events
commit 6b099d9b upstream. Currently, the intel_bts driver relies on the DS area allocated by the x86_pmu code in its event_init() path, which is a bug: creating a BTS event while no x86_pmu events are present results in a NULL pointer dereference. The same DS area is also used by PEBS sampling, which makes it quite a bit trickier to have a separate one for intel_bts' purposes. This patch makes intel_bts driver use the same DS allocation and reference counting code as x86_pmu to make sure it is always present when either intel_bts or x86_pmu need it. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: acme@infradead.org Cc: adrian.hunter@intel.com Link: http://lkml.kernel.org/r/1434024837-9916-2-git-send-email-alexander.shishkin@linux.intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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