The existing ctx->vfsroot is dangerous. We take it from the root task via: ctx->root_task->fs->root and don't take a ref on the 'fs' in there. We also take a ref on the fs.root which is worthless. So, replace ctx->vfsroot with a reference to the 'fs' instead. This gives us easy access to fs.root later on, and also lets us do proper refcounting. This, of course, eventually needs to be done per-process but this should at least remove a potential oops. --- linux-2.6.git-dave/checkpoint/checkpoint.c | 7 ++----- linux-2.6.git-dave/checkpoint/ckpt_file.c | 2 +- linux-2.6.git-dave/checkpoint/ckpt_mem.c | 2 +- linux-2.6.git-dave/checkpoint/sys.c | 4 ++-- linux-2.6.git-dave/include/linux/checkpoint.h | 2 +- 5 files changed, 7 insertions(+), 10 deletions(-) diff -puN checkpoint/checkpoint.c~fix-cr_ctx_checkpoint-locking checkpoint/checkpoint.c --- linux-2.6.git/checkpoint/checkpoint.c~fix-cr_ctx_checkpoint-locking 2008-12-02 10:21:52.000000000 -0800 +++ linux-2.6.git-dave/checkpoint/checkpoint.c 2008-12-02 10:21:52.000000000 -0800 @@ -511,12 +511,9 @@ static int cr_ctx_checkpoint(struct cr_c * assume checkpointer is in container's root vfs * FIXME: this works for now, but will change with real containers */ - task_lock(ctx->root_task); - ctx->vfsroot = &ctx->root_task->fs->root; - task_unlock(ctx->root_task); - if (!ctx->vfsroot) + ctx->fs = get_fs_struct(ctx->root_task); + if (!ctx->fs) return -EAGAIN; - path_get(ctx->vfsroot); return 0; } diff -puN checkpoint/ckpt_file.c~fix-cr_ctx_checkpoint-locking checkpoint/ckpt_file.c --- linux-2.6.git/checkpoint/ckpt_file.c~fix-cr_ctx_checkpoint-locking 2008-12-02 10:21:52.000000000 -0800 +++ linux-2.6.git-dave/checkpoint/ckpt_file.c 2008-12-02 10:46:56.000000000 -0800 @@ -117,7 +117,7 @@ static int cr_write_fd_data(struct cr_ct if (ret < 0) return ret; - return cr_write_fname(ctx, &file->f_path, ctx->vfsroot); + return cr_write_fname(ctx, &file->f_path, &ctx->fs.root); } /** diff -puN checkpoint/ckpt_mem.c~fix-cr_ctx_checkpoint-locking checkpoint/ckpt_mem.c --- linux-2.6.git/checkpoint/ckpt_mem.c~fix-cr_ctx_checkpoint-locking 2008-12-02 10:21:52.000000000 -0800 +++ linux-2.6.git-dave/checkpoint/ckpt_mem.c 2008-12-02 10:21:52.000000000 -0800 @@ -436,7 +436,7 @@ static int cr_write_vma(struct cr_ctx *c /* save the file name, if relevant */ if (vma->vm_file) { - ret = cr_write_fname(ctx, &vma->vm_file->f_path, ctx->vfsroot); + ret = cr_write_fname(ctx, &vma->vm_file->f_path, &ctx->fs.root); if (ret < 0) return ret; } diff -puN checkpoint/sys.c~fix-cr_ctx_checkpoint-locking checkpoint/sys.c --- linux-2.6.git/checkpoint/sys.c~fix-cr_ctx_checkpoint-locking 2008-12-02 10:21:52.000000000 -0800 +++ linux-2.6.git-dave/checkpoint/sys.c 2008-12-02 10:21:52.000000000 -0800 @@ -152,8 +152,8 @@ static void cr_ctx_free(struct cr_ctx *c kfree(ctx->hbuf); - if (ctx->vfsroot) - path_put(ctx->vfsroot); + if (ctx->fs) + put_fs_struct(ctx->fs); cr_pgarr_free(ctx); cr_objhash_free(ctx); diff -puN include/linux/checkpoint.h~fix-cr_ctx_checkpoint-locking include/linux/checkpoint.h --- linux-2.6.git/include/linux/checkpoint.h~fix-cr_ctx_checkpoint-locking 2008-12-02 10:21:52.000000000 -0800 +++ linux-2.6.git-dave/include/linux/checkpoint.h 2008-12-02 10:21:52.000000000 -0800 @@ -41,7 +41,7 @@ struct cr_ctx { struct list_head pgarr_list; /* page array to dump VMA contents */ - struct path *vfsroot; /* container root (FIXME) */ + struct fs_struct *fs; /* container root/pwd (FIXME) */ /* [multi-process checkpoint] */ struct task_struct **tasks_arr; /* array of all tasks [checkpoint] */ _ _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers