[PATCH] checkpoint: handle sigaltstack

[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-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
---
 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

Re: [PATCH] checkpoint: handle sigaltstack

[Dan Smith]

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

This makes all my sigaltstack-related tests work.  Thanks!

Tested-by: Dan Smith <danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>

-- 
Dan Smith
IBM Linux Technology Center
email: danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org

Re: [PATCH] checkpoint: handle sigaltstack

[Oren Laadan]

Acked, and pulled to v22-dev, thanks.

Oren.

On 07/14/2010 11:23 AM, Nathan Lynch wrote:
> 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-e+AXbWqSrlAAvxtiuMwx3w@public.gmane.org>
> ---
>  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 =