Peter Zijlstra c3c87e7704 perf: Tighten (and fix) the grouping condition ...

The fix from 9fc81d8742 ("perf: Fix events installation during
moving group") was incomplete in that it failed to recognise that
creating a group with events for different CPUs is semantically
broken -- they cannot be co-scheduled.

Furthermore, it leads to real breakage where, when we create an event
for CPU Y and then migrate it to form a group on CPU X, the code gets
confused where the counter is programmed -- triggered in practice
as well by me via the perf fuzzer.

Fix this by tightening the rules for creating groups. Only allow
grouping of counters that can be co-scheduled in the same context.
This means for the same task and/or the same cpu.

Fixes: 9fc81d8742 ("perf: Fix events installation during moving group")
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Linus Torvalds <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

2015-01-28 13:17:35 +01:00

..

callchain.c

Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

2014-10-15 07:48:18 +02:00

core.c

perf: Tighten (and fix) the grouping condition

2015-01-28 13:17:35 +01:00

hw_breakpoint.c

perf: Fix and clean up initialization of pmu::event_idx

2014-10-28 10:51:01 +01:00

internal.h

perf: Fix arch_perf_out_copy_user default

2013-11-06 12:34:25 +01:00

Makefile

…

ring_buffer.c

perf: Optimize ring-buffer write by depending on control dependencies

2013-12-11 15:53:22 +01:00

uprobes.c

Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux

2014-12-15 15:52:01 -08:00