[CRIU] [PATCH 3/6] criu: dump: prepare parasite control for threads at infect time
Laurent Dufour
ldufour at linux.vnet.ibm.com
Thu Aug 16 19:08:56 MSK 2018
On 13/08/2018 15:29, Mike Rapoport wrote:
> Currently parasite_thread_ctl for non-leader threads is initialized after we
> stop the compel daemon. Moving this initialization earlier will allow us to
> make stack pointers of all threads available during memory dump.
I've to admit that I'm no more accurate on that part, so my question could make
no sense: What would happen if a thread dies while dumping the memory, which is
quite a long operation ?
Cheers,
Laurent.
> Signed-off-by: Mike Rapoport <rppt at linux.vnet.ibm.com>
> ---
> criu/cr-dump.c | 3 ++-
> criu/include/parasite-syscall.h | 6 ++++--
> criu/include/pstree.h | 1 +
> criu/parasite-syscall.c | 40 +++++++++++++++++++++++++++++++++-------
> 4 files changed, 40 insertions(+), 10 deletions(-)
>
> diff --git a/criu/cr-dump.c b/criu/cr-dump.c
> index 6596793..ec5e1e4 100644
> --- a/criu/cr-dump.c
> +++ b/criu/cr-dump.c
> @@ -842,6 +842,7 @@ static int collect_file_locks(void)
> static int dump_task_thread(struct parasite_ctl *parasite_ctl,
> const struct pstree_item *item, int id)
> {
> + struct parasite_thread_ctl *tctl = dmpi(item)->thread_ctls[id];
> struct pid *tid = &item->threads[id];
> CoreEntry *core = item->core[id];
> pid_t pid = tid->real;
> @@ -852,7 +853,7 @@ static int dump_task_thread(struct parasite_ctl *parasite_ctl,
> pr_info("Dumping core for thread (pid: %d)\n", pid);
> pr_info("----------------------------------------\n");
>
> - ret = parasite_dump_thread_seized(parasite_ctl, id, tid, core);
> + ret = parasite_dump_thread_seized(tctl, parasite_ctl, id, tid, core);
> if (ret) {
> pr_err("Can't dump thread for pid %d\n", pid);
> goto err;
> diff --git a/criu/include/parasite-syscall.h b/criu/include/parasite-syscall.h
> index 0e9d340..c86a724 100644
> --- a/criu/include/parasite-syscall.h
> +++ b/criu/include/parasite-syscall.h
> @@ -21,6 +21,7 @@ struct parasite_dump_cgroup_args;
> struct rt_sigframe;
>
> struct parasite_ctl;
> +struct parasite_thread_ctl;
>
> extern int parasite_dump_sigacts_seized(struct parasite_ctl *ctl, struct pstree_item *);
> extern int parasite_dump_itimers_seized(struct parasite_ctl *ctl, struct pstree_item *);
> @@ -32,8 +33,9 @@ extern int parasite_dump_posix_timers_seized(struct proc_posix_timers_stat *proc
> extern int parasite_dump_misc_seized(struct parasite_ctl *ctl, struct parasite_dump_misc *misc);
> extern int parasite_dump_creds(struct parasite_ctl *ctl, struct _CredsEntry *ce);
> extern int parasite_dump_thread_leader_seized(struct parasite_ctl *ctl, int pid, struct _CoreEntry *core);
> -extern int parasite_dump_thread_seized(struct parasite_ctl *ctl, int id,
> - struct pid *tid, struct _CoreEntry *core);
> +extern int parasite_dump_thread_seized(struct parasite_thread_ctl *tctl,
> + struct parasite_ctl *ctl, int id,
> + struct pid *tid, struct _CoreEntry *core);
> extern int dump_thread_core(int pid, CoreEntry *core,
> const struct parasite_dump_thread *dt);
>
> diff --git a/criu/include/pstree.h b/criu/include/pstree.h
> index 508d6df..4913aae 100644
> --- a/criu/include/pstree.h
> +++ b/criu/include/pstree.h
> @@ -56,6 +56,7 @@ struct dmp_info {
> struct ns_id *netns;
> struct page_pipe *mem_pp;
> struct parasite_ctl *parasite_ctl;
> + struct parasite_thread_ctl **thread_ctls;
> };
>
> static inline struct dmp_info *dmpi(const struct pstree_item *i)
> diff --git a/criu/parasite-syscall.c b/criu/parasite-syscall.c
> index 267d3fa..366c6c9 100644
> --- a/criu/parasite-syscall.c
> +++ b/criu/parasite-syscall.c
> @@ -162,7 +162,8 @@ int parasite_dump_thread_leader_seized(struct parasite_ctl *ctl, int pid, CoreEn
> return dump_thread_core(pid, core, args);
> }
>
> -int parasite_dump_thread_seized(struct parasite_ctl *ctl, int id,
> +int parasite_dump_thread_seized(struct parasite_thread_ctl *tctl,
> + struct parasite_ctl *ctl, int id,
> struct pid *tid, CoreEntry *core)
> {
> struct parasite_dump_thread *args;
> @@ -171,7 +172,6 @@ int parasite_dump_thread_seized(struct parasite_ctl *ctl, int id,
> CredsEntry *creds = tc->creds;
> struct parasite_dump_creds *pc;
> int ret;
> - struct parasite_thread_ctl *tctl;
>
> BUG_ON(id == 0); /* Leader is dumped in dump_task_core_all */
>
> @@ -180,10 +180,6 @@ int parasite_dump_thread_seized(struct parasite_ctl *ctl, int id,
> pc = args->creds;
> pc->cap_last_cap = kdat.last_cap;
>
> - tctl = compel_prepare_thread(ctl, pid);
> - if (!tctl)
> - return -1;
> -
> tc->has_blk_sigset = true;
> memcpy(&tc->blk_sigset, compel_thread_sigmask(tctl), sizeof(k_rtsigset_t));
> ret = compel_get_thread_regs(tctl, save_task_regs, core);
> @@ -468,12 +464,39 @@ static int make_sigframe(void *arg, struct rt_sigframe *sf, struct rt_sigframe *
> return construct_sigframe(sf, rtsf, bs, (CoreEntry *)arg);
> }
>
> +static int parasite_prepare_threads(struct parasite_ctl *ctl,
> + struct pstree_item *item)
> +{
> + struct parasite_thread_ctl **thread_ctls;
> + int i;
> +
> + thread_ctls = xzalloc(sizeof(*thread_ctls) * item->nr_threads);
> + if (!thread_ctls)
> + return -1;
> +
> + for (i = 0; i < item->nr_threads; i++) {
> + struct pid *tid = &item->threads[i];
> +
> + if (item->pid->real == tid->real)
> + continue;
> +
> + thread_ctls[i] = compel_prepare_thread(ctl, tid->real);
> + if (!thread_ctls[i])
> + return -1;
> + }
> +
> + dmpi(item)->thread_ctls = thread_ctls;
> +
> + return 0;
> +}
> +
> struct parasite_ctl *parasite_infect_seized(pid_t pid, struct pstree_item *item,
> struct vm_area_list *vma_area_list)
> {
> struct parasite_ctl *ctl;
> struct infect_ctx *ictx;
> unsigned long p;
> + int ret;
>
> BUG_ON(item->threads[0].real != pid);
>
> @@ -487,6 +510,10 @@ struct parasite_ctl *parasite_infect_seized(pid_t pid, struct pstree_item *item,
> if (!ctl)
> return NULL;
>
> + ret = parasite_prepare_threads(ctl, item);
> + if (ret)
> + return NULL;
> +
> ictx = compel_infect_ctx(ctl);
>
> ictx->open_proc = do_open_proc;
> @@ -532,4 +559,3 @@ struct parasite_ctl *parasite_infect_seized(pid_t pid, struct pstree_item *item,
>
> return ctl;
> }
> -
>
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