[RFC,PATCH 02/14] signals: check ->group_stop_count aftertracehook_get_signal()

From: Oleg Nesterov
Date: Tue Nov 24 2009 - 15:07:18 EST


(already in mm: signals-check-group_stop_count-after-tracehook_get_signal.patch)

Move the call to do_signal_stop() down, after tracehook call.
This makes ->group_stop_count condition visible to tracers before
do_signal_stop() will participate in this group-stop.

Currently the patch has no effect, tracehook_get_signal() always
returns 0.

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Roland McGrath <roland@xxxxxxxxxx>
---

kernel/signal.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

--- V1/kernel/signal.c~2_DO_SIGNAL_STOP_AFTER_TRACEHOOK 2009-11-24 19:46:51.000000000 +0100
+++ V1/kernel/signal.c 2009-11-24 19:51:13.000000000 +0100
@@ -1807,11 +1807,6 @@ relock:

for (;;) {
struct k_sigaction *ka;
-
- if (unlikely(signal->group_stop_count > 0) &&
- do_signal_stop(0))
- goto relock;
-
/*
* Tracing can induce an artifical signal and choose sigaction.
* The return value in @signr determines the default action,
@@ -1823,6 +1818,10 @@ relock:
if (unlikely(signr != 0))
ka = return_ka;
else {
+ if (unlikely(signal->group_stop_count > 0) &&
+ do_signal_stop(0))
+ goto relock;
+
signr = dequeue_signal(current, &current->blocked,
info);


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