Pulled, thanks.
Nathan Lynch wrote:
> Off-by-one error: the stack address passed to clone/clone_with_pids
> must be within the region allocated. (Also, arithmetic on void * is a
> gcc extension; change the relevant variables to char *).
>
> Signed-off-by: Nathan Lynch <ntl@xxxxxxxxx>
> ---
> mktree.c | 15 ++++++++-------
> 1 files changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/mktree.c b/mktree.c
> index 63be82d..2d8d796 100644
> --- a/mktree.c
> +++ b/mktree.c
> @@ -1367,18 +1367,19 @@ int ckpt_fork_stub(void *data)
> static pid_t ckpt_fork_child(struct ckpt_ctx *ctx, struct task *child)
> {
> struct target_pid_set pid_set;
> - void *stack = NULL;
> + char *stack_region;
> + char *stack_start;
> unsigned long flags = SIGCHLD;
> pid_t pid = 0;
>
> ckpt_dbg("forking child vpid %d flags %#x\n", child->pid, child->flags);
>
> - stack = malloc(PTHREAD_STACK_MIN);
> - if (!stack) {
> + stack_region = malloc(PTHREAD_STACK_MIN);
> + if (!stack_region) {
> perror("stack malloc");
> return -1;
> }
> - stack += PTHREAD_STACK_MIN;
> + stack_start = stack_region + PTHREAD_STACK_MIN - 1;
>
> pid_set.target_pids = &pid;
> pid_set.num_pids = 1;
> @@ -1406,15 +1407,15 @@ static pid_t ckpt_fork_child(struct ckpt_ctx *ctx, struct task *child)
> else
> child->real_parent = _getpid();
>
> - pid = clone_with_pids(ckpt_fork_stub, stack, flags, &pid_set, child);
> + pid = clone_with_pids(ckpt_fork_stub, stack_start, flags, &pid_set, child);
> if (pid < 0) {
> perror("clone");
> - free(stack - PTHREAD_STACK_MIN);
> + free(stack_region);
> return -1;
> }
>
> if (!(child->flags & TASK_THREAD))
> - free(stack - PTHREAD_STACK_MIN);
> + free(stack_region);
>
> ckpt_dbg("forked child vpid %d (asked %d)\n", pid, child->pid);
> return pid;
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