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authorOleg Nesterov <oleg@redhat.com>2012-12-29 17:49:11 +0100
committerOleg Nesterov <oleg@redhat.com>2013-02-08 17:47:11 +0100
commitda1816b1caeccdff04531e763bb35d7caa3ed19f (patch)
treebbf3b1eda3f969a5115770f0aa1081feafd871cb /include/linux
parent8a7f2fa0dea3b019500961b86d765e6fdd4bffb2 (diff)
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/linux')
-rw-r--r--include/linux/uprobes.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index c2df6934fdc6..95d0002efda5 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,