kernel_optimize_test/kernel/events
Oleg Nesterov da1816b1ca uprobes: Teach handler_chain() to filter out the probed task
Currrently the are 2 problems with pre-filtering:

1. It is not possible to add/remove a task (mm) after uprobe_register()

2. A forked child inherits all breakpoints and uprobe_consumer can not
   control this.

This patch does the first step to improve the filtering. handler_chain()
removes the breakpoints installed by this uprobe from current->mm if all
handlers return UPROBE_HANDLER_REMOVE.

Note that handler_chain() relies on ->register_rwsem to avoid the race
with uprobe_register/unregister which can add/del a consumer, or even
remove and then insert the new uprobe at the same address.

Perhaps we will add uprobe_apply_mm(uprobe, mm, is_register) and teach
copy_mm() to do filter(UPROBE_FILTER_FORK), but I think this change makes
sense anyway.

Note: instead of checking the retcode from uc->handler, we could add
uc->filter(UPROBE_FILTER_BPHIT). But I think this is not optimal to
call 2 hooks in a row. This buys nothing, and if handler/filter do
something nontrivial they will probably do the same work twice.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2013-02-08 17:47:11 +01:00
..
callchain.c perf: Add attribute to filter out callchains 2012-08-10 12:40:57 -03:00
core.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-12-17 15:44:47 -08:00
hw_breakpoint.c perf, powerpc: Fix hw breakpoints returning -ENOSPC 2012-10-30 10:07:58 +01:00
internal.h perf: Add ability to attach user stack dump to sample 2012-08-10 12:17:58 -03:00
Makefile uprobes: Move to kernel/events/ 2012-02-22 11:08:00 +01:00
ring_buffer.c perf: Add perf_output_skip function to skip bytes in sample 2012-08-10 12:16:22 -03:00
uprobes.c uprobes: Teach handler_chain() to filter out the probed task 2013-02-08 17:47:11 +01:00