The main point is for new-comers to the checkpoint/restart tree to
be able to help us debug their otherwise mysterious checkpoint failures.
Signed-off-by: Serge E. Hallyn <serue@xxxxxxxxxx>
---
checkpoint/checkpoint.c | 28 +++++++++++++++++++++++-----
checkpoint/files.c | 37 ++++++++++++++++++++++++++++++-------
checkpoint/memory.c | 17 ++++++++++++++---
3 files changed, 67 insertions(+), 15 deletions(-)
diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c
index c19f812..7beee08 100644
--- a/checkpoint/checkpoint.c
+++ b/checkpoint/checkpoint.c
@@ -295,6 +295,8 @@ static int may_checkpoint_task(struct ckpt_ctx *ctx, struct task_struct *t)
if (t->exit_state == EXIT_DEAD) {
pr_warning("c/r: task %d is EXIT_DEAD\n", task_pid_vnr(t));
+ __ckpt_write_err(ctx, "task %d (%s) in state EXIT_DEAD",
+ task_pid_vnr(t), t->comm);
return -EAGAIN;
}
@@ -335,12 +337,21 @@ static int may_checkpoint_task(struct ckpt_ctx *ctx, struct task_struct *t)
rcu_read_lock();
nsproxy = task_nsproxy(t);
- if (nsproxy->mnt_ns != ctx->root_nsproxy->mnt_ns)
+ if (nsproxy->mnt_ns != ctx->root_nsproxy->mnt_ns) {
+ __ckpt_write_err(ctx, "task %d (%s) in bad mnt_ns",
+ task_pid_vnr(t), t->comm);
ret = -EPERM;
- if (nsproxy->pid_ns != ctx->root_nsproxy->pid_ns)
+ }
+ if (nsproxy->pid_ns != ctx->root_nsproxy->pid_ns) {
+ __ckpt_write_err(ctx, "task %d (%s) in bad pid_ns",
+ task_pid_vnr(t), t->comm);
ret = -EPERM;
- if (nsproxy->net_ns != ctx->root_nsproxy->net_ns)
+ }
+ if (nsproxy->net_ns != ctx->root_nsproxy->net_ns) {
+ __ckpt_write_err(ctx, "task %d (%s) in bad net_ns",
+ task_pid_vnr(t), t->comm);
ret = -EPERM;
+ }
rcu_read_unlock();
return ret;
@@ -629,8 +640,11 @@ static int init_checkpoint_ctx(struct ckpt_ctx *ctx, pid_t pid)
/* container init ? */
ctx->root_init = is_container_init(task);
- if (!(ctx->uflags & CHECKPOINT_SUBTREE) && !ctx->root_init)
+ if (!(ctx->uflags & CHECKPOINT_SUBTREE) && !ctx->root_init) {
+ ckpt_write_err(ctx, "Task is not container init"
+ " and CHECKPOINT_SUBTREE was not specified");
return -EINVAL; /* cleanup by ckpt_ctx_free() */
+ }
/* root vfs (FIX: WILL CHANGE with mnt-ns etc */
task_lock(ctx->root_task);
@@ -669,9 +683,12 @@ long do_checkpoint(struct ckpt_ctx *ctx, pid_t pid)
* and then compare to the objects' real user counts.
*/
ret = collect_objects(ctx);
- if (ret < 0)
+ if (ret < 0) {
+ ckpt_write_err(ctx, "Error %d collecting objects", ret);
goto out;
+ }
if (!ckpt_obj_contained(ctx)) {
+ ckpt_write_err(ctx, "Container had leaks");
ret = -EAGAIN;
goto out;
}
@@ -689,6 +706,7 @@ long do_checkpoint(struct ckpt_ctx *ctx, pid_t pid)
/* verify that all objects were indeed visited */
if (!ckpt_obj_visited(ctx)) {
+ ckpt_write_err(ctx, "Not all objects were visited");
ret = -EAGAIN;
goto out;
}
diff --git a/checkpoint/files.c b/checkpoint/files.c
index 204055b..d16916a 100644
--- a/checkpoint/files.c
+++ b/checkpoint/files.c
@@ -84,8 +84,11 @@ int checkpoint_fname(struct ckpt_ctx *ctx, struct path *path, struct path *root)
if (!IS_ERR(fname))
ret = ckpt_write_obj_type(ctx, fname, flen,
CKPT_HDR_FILE_NAME);
- else
+ else {
+ ckpt_write_err(ctx, "Error writing file name for %s\n",
+ path->dentry->d_name.name);
ret = PTR_ERR(fname);
+ }
kfree(buf);
return ret;
@@ -192,16 +195,23 @@ EXPORT_SYMBOL(generic_file_checkpoint);
int checkpoint_file(struct ckpt_ctx *ctx, void *ptr)
{
struct file *file = (struct file *) ptr;
+ int ret;
if (!file->f_op || !file->f_op->checkpoint) {
+ ckpt_write_err(ctx, "Unsupproted file type: %pS", file->f_op);
ckpt_debug("f_op lacks checkpoint handler: %pS\n", file->f_op);
return -EBADF;
}
if (d_unlinked(file->f_dentry)) {
+ ckpt_write_err(ctx, "Unlinked file: %s", file->f_dentry->d_name.name);
ckpt_debug("unlinked files are unsupported\n");
return -EBADF;
}
- return file->f_op->checkpoint(ctx, file);
+ ret = file->f_op->checkpoint(ctx, file);
+ if (ret)
+ ckpt_write_err(ctx, "f_op->checkpoint returned %d for %s",
+ ret, file->f_dentry->d_name.name);
+ return ret;
}
/**
@@ -238,8 +248,10 @@ static int checkpoint_file_desc(struct ckpt_ctx *ctx,
/* sanity check (although this shouldn't happen) */
ret = -EBADF;
- if (!file)
+ if (!file) {
+ ckpt_write_err(ctx, "File no longer exists?");
goto out;
+ }
/*
* if seen first time, this will add 'file' to the objhash, keep
@@ -312,8 +324,10 @@ int checkpoint_obj_file_table(struct ckpt_ctx *ctx, struct task_struct *t)
int objref;
files = get_files_struct(t);
- if (!files)
+ if (!files) {
+ ckpt_write_err(ctx, "couldn't get files struct");
return -EBUSY;
+ }
objref = checkpoint_obj(ctx, files, CKPT_OBJ_FILE_TABLE);
put_files_struct(files);
@@ -332,8 +346,12 @@ int ckpt_collect_file(struct ckpt_ctx *ctx, struct file *file)
if (ret <= 0)
return ret;
/* if first time for this file (ret > 0), invoke ->collect() */
- if (file->f_op->collect)
+ if (file->f_op->collect) {
ret = file->f_op->collect(ctx, file);
+ if (ret)
+ ckpt_write_err(ctx, "Error %d collecing file %s",
+ ret, file->f_dentry->d_name.name);
+ }
return ret;
}
@@ -351,8 +369,10 @@ static int collect_file_desc(struct ckpt_ctx *ctx,
get_file(file);
rcu_read_unlock();
- if (!file)
+ if (!file) {
+ ckpt_write_err(ctx, "Failed to get file");
return -EAGAIN;
+ }
ret = ckpt_collect_file(ctx, file);
fput(file);
@@ -392,8 +412,11 @@ int ckpt_collect_file_table(struct ckpt_ctx *ctx, struct task_struct *t)
int ret;
files = get_files_struct(t);
- if (!files)
+ if (!files) {
+ ckpt_write_err(ctx, "Could not get files struct task %d (%s)",
+ task_pid_vnr(t), t->comm);
return -EBUSY;
+ }
ret = collect_file_table(ctx, files);
put_files_struct(files);
diff --git a/checkpoint/memory.c b/checkpoint/memory.c
index 487efbd..a6bbd1f 100644
--- a/checkpoint/memory.c
+++ b/checkpoint/memory.c
@@ -556,6 +556,7 @@ int generic_vma_checkpoint(struct ckpt_ctx *ctx, struct vm_area_struct *vma,
if (vma->vm_flags & CKPT_VMA_NOT_SUPPORTED) {
pr_warning("c/r: unsupported VMA %#lx\n", vma->vm_flags);
+ ckpt_write_err(ctx, "unsupported VMA %#lx", vma->vm_flags);
return -ENOSYS;
}
@@ -645,6 +646,7 @@ static int anonymous_checkpoint(struct ckpt_ctx *ctx,
/* should be private anonymous ... verify that this is the case */
if (vma->vm_flags & CKPT_VMA_NOT_SUPPORTED) {
pr_warning("c/r: unsupported VMA %#lx\n", vma->vm_flags);
+ ckpt_write_err(ctx, "unsupported VMA %#lx", vma->vm_flags);
return -ENOSYS;
}
@@ -711,8 +713,11 @@ static int do_checkpoint_mm(struct ckpt_ctx *ctx, struct mm_struct *mm)
ret = (*vma->vm_ops->checkpoint)(ctx, vma);
else
ret = -ENOSYS;
- if (ret < 0)
+ if (ret < 0) {
+ ckpt_write_err(ctx, "vma checkpoint returrned %d",
+ ret);
goto out;
+ }
}
ret = checkpoint_mm_context(ctx, mm);
@@ -758,15 +763,21 @@ static int collect_mm(struct ckpt_ctx *ctx, struct mm_struct *mm)
down_read(&mm->mmap_sem);
if (mm->exe_file) {
ret = ckpt_collect_file(ctx, mm->exe_file);
- if (ret < 0)
+ if (ret < 0) {
+ ckpt_write_err(ctx, "Err %d collecting mm->exe_file",
+ ret);
goto out;
+ }
}
for (vma = mm->mmap; vma; vma = vma->vm_next) {
file = vma->vm_file;
if (file) {
ret = ckpt_collect_file(ctx, file);
- if (ret < 0)
+ if (ret < 0) {
+ ckpt_write_err(ctx, "Err %d collecting vm_file",
+ ret);
break;
+ }
}
}
out:
--
1.6.1
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