[Devel] [PATCH] checkpoint: handle sigaltstack

[Nathan Lynch]

sigaltstack(2) manipulates two fields in task_struct; save and restore
these.  Without this change the alternate stack is not used after
restart.

Signed-off-by: Nathan Lynch <ntl at pobox.com>
---
 include/linux/checkpoint_hdr.h |    2 ++
 kernel/checkpoint/process.c    |    6 ++++++
 2 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
index c8383c0..bc4ef43 100644
--- a/include/linux/checkpoint_hdr.h
+++ b/include/linux/checkpoint_hdr.h
@@ -380,6 +380,8 @@ struct ckpt_hdr_task {
 
 	__u64 set_child_tid;
 	__u64 clear_child_tid;
+	__u64 sas_ss_sp;
+	__u32 sas_ss_size;
 } __attribute__((aligned(8)));
 
 /* Posix capabilities */
diff --git a/kernel/checkpoint/process.c b/kernel/checkpoint/process.c
index f6f3771..936675a 100644
--- a/kernel/checkpoint/process.c
+++ b/kernel/checkpoint/process.c
@@ -138,6 +138,9 @@ static int checkpoint_task_struct(struct ckpt_ctx *ctx, struct task_struct *t)
 	h->exit_state = t->exit_state;
 	h->exit_code = t->exit_code;
 
+	h->sas_ss_sp = t->sas_ss_sp;
+	h->sas_ss_size = t->sas_ss_size;
+
 	if (t->exit_state) {
 		/* zombie - skip remaining state */
 		BUG_ON(t->exit_state != EXIT_ZOMBIE);
@@ -542,6 +545,9 @@ static int restore_task_struct(struct ckpt_ctx *ctx)
 		t->exit_signal = h->exit_signal;
 		t->pdeath_signal = h->pdeath_signal;
 
+		t->sas_ss_sp = (unsigned long)h->sas_ss_sp;
+		t->sas_ss_size = h->sas_ss_size;
+
 		t->set_child_tid =
 			(int __user *) (unsigned long) h->set_child_tid;
 		t->clear_child_tid =
-- 
1.7.1.1

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