Alas they uglify the error paths during restart, but I can't count on two hands the number of times I've had to add these and recompile to find one silly bug or other, so I suggest that it may be worth having these in the code anyway.
Signed-off-by: Serge E. Hallyn <[email protected]> --- checkpoint/restart.c | 50 +++++++++++++++++++++++++++++++++++++++----------- 1 files changed, 39 insertions(+), 11 deletions(-) diff --git a/checkpoint/restart.c b/checkpoint/restart.c index 1085ed5..ebdd5ba 100644 --- a/checkpoint/restart.c +++ b/checkpoint/restart.c @@ -662,6 +662,7 @@ static int restore_activate_next(struct ckpt_ctx *ctx) rcu_read_unlock(); if (!task) { + ckpt_debug("could not find task %d\n", pid); restore_notify_error(ctx, -ESRCH); return -ESRCH; } @@ -685,6 +686,7 @@ static int wait_task_active(struct ckpt_ctx *ctx) ckpt_debug("active %d < %d (ret %d)\n", ctx->active_pid, ctx->nr_pids, ret); if (!ret && ckpt_test_ctx_error(ctx)) { + ckpt_debug("wait_event_interruptible returned %d\n", ret); force_sig(SIGKILL, current); ret = -EBUSY; } @@ -827,20 +829,25 @@ static int do_restore_task(void) /* wait for our turn, do the restore, and tell next task in line */ ret = wait_task_active(ctx); - if (ret < 0) + if (ret < 0) { + ckpt_debug("wait_task_active returned %d\n", ret); goto out; + } ckpt_debug_log_running(ctx); zombie = restore_task(ctx); if (zombie < 0) { + ckpt_debug("restore_task returned %d\n", ret); ret = zombie; goto out; } ret = restore_activate_next(ctx); - if (ret < 0) + if (ret < 0) { + ckpt_debug("restore_activate_next returned %d\n", ret); goto out; + } /* * zombie: we're done here; do_exit() will notice the @ctx on @@ -855,6 +862,8 @@ static int do_restore_task(void) restore_task_done(ctx); ret = wait_task_sync(ctx); + if (ret) + ckpt_debug("wait_task_sync returned %d\n", ret); out: old_ctx = xchg(¤t->checkpoint_ctx, NULL); if (old_ctx) @@ -970,12 +979,14 @@ static int wait_all_tasks_finish(struct ckpt_ctx *ctx) BUG_ON(ctx->active_pid != -1); ret = restore_activate_next(ctx); - if (ret < 0) + if (ret < 0) { + ckpt_debug("restore_activate_next returned %d\n", ret); return ret; + } ret = wait_for_completion_interruptible(&ctx->complete); - ckpt_debug("final sync kflags %#lx\n", ctx->kflags); + ckpt_debug("final sync kflags %#lx (ret %d)\n", ctx->kflags, ret); /* * Usually when restart fails, the restarting task will first * set @ctx->errno before waking us up. In the rare event that @@ -1051,18 +1062,24 @@ static int do_restore_coord(struct ckpt_ctx *ctx, pid_t pid) ckpt_debug_log_running(ctx); ret = restore_read_header(ctx); - if (ret < 0) + if (ret < 0) { + ckpt_debug("restore_read_header returned %d\n", ret); return ret; + } ret = restore_read_tree(ctx); - if (ret < 0) + if (ret < 0) { + ckpt_debug("restore_read_tree returned %d\n", ret); return ret; + } if ((ctx->uflags & RESTART_TASKSELF) && ctx->nr_pids != 1) return -EINVAL; ret = init_restart_ctx(ctx, pid); - if (ret < 0) + if (ret < 0) { + ckpt_debug("init_restart_ctx returned %d\n", ret); return ret; + } /* * Populate own ->checkpoint_ctx: if an ancestor attempts to @@ -1094,8 +1111,10 @@ static int do_restore_coord(struct ckpt_ctx *ctx, pid_t pid) } else { /* prepare descendants' t->checkpoint_ctx point to coord */ ret = prepare_descendants(ctx, ctx->root_task); - if (ret < 0) + if (ret < 0) { + ckpt_debug("prepare_descendants returned %d", ret); goto out; + } /* tell tasks we're ready for them to dec ctx->nr_running */ wake_up_all(&ctx->waitq); @@ -1108,17 +1127,23 @@ static int do_restore_coord(struct ckpt_ctx *ctx, pid_t pid) /* wait for all other tasks to complete do_restore_task() */ ret = wait_all_tasks_finish(ctx); - if (ret < 0) + if (ret < 0) { + ckpt_debug("wait_all_tasks_finish returned %d", ret); goto out; + } } ret = deferqueue_run(ctx->deferqueue); /* run deferred work */ - if (ret < 0) + if (ret < 0) { + ckpt_debug("deferqueue_run returned %d\n", ret); goto out; + } ret = restore_read_tail(ctx); - if (ret < 0) + if (ret < 0) { + ckpt_debug("restore_read_tail returned %d\n", ret); goto out; + } if (ctx->uflags & RESTART_FROZEN) { ret = cgroup_freezer_make_frozen(ctx->root_task); @@ -1202,6 +1227,9 @@ long do_restart(struct ckpt_ctx *ctx, pid_t pid, unsigned long flags) else ret = do_restore_task(); + if (ret < 0) + ckpt_debug("ret %ld\n", ret); + /* restart(2) isn't idempotent: should not be auto-restarted */ if (ret == -ERESTARTSYS || ret == -ERESTARTNOINTR || ret == -ERESTARTNOHAND || ret == -ERESTART_RESTARTBLOCK) -- 1.6.1 _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
