diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2012-12-29 16:49:11 (GMT) |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2013-02-08 16:47:11 (GMT) |
| commit | da1816b1caeccdff04531e763bb35d7caa3ed19f (patch) | |
| tree | bbf3b1eda3f969a5115770f0aa1081feafd871cb /include | |
| parent | 8a7f2fa0dea3b019500961b86d765e6fdd4bffb2 (diff) | |
| download | linux-da1816b1caeccdff04531e763bb35d7caa3ed19f.tar.xz | |
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>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/uprobes.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index c2df693..95d0002 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -35,6 +35,9 @@ struct inode; # include <asm/uprobes.h> #endif +#define UPROBE_HANDLER_REMOVE 1 +#define UPROBE_HANDLER_MASK 1 + enum uprobe_filter_ctx { UPROBE_FILTER_REGISTER, UPROBE_FILTER_UNREGISTER, |