From 444f378b237a0f728f5c4aba752c08d13c209344 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 30 Jan 2007 13:35:18 -0800 Subject: [PATCH] Revert "[PATCH] namespaces: fix exit race by splitting exit" This reverts commit 7a238fcba0629b6f2edbcd37458bae56fcf36be5 in preparation for a better and simpler fix proposed by Eric Biederman (and fixed up by Serge Hallyn) Acked-by: Serge E. Hallyn Signed-off-by: Linus Torvalds --- include/linux/nsproxy.h | 30 +++++++++++------------------- kernel/exit.c | 6 ++---- kernel/fork.c | 4 ++-- kernel/nsproxy.c | 16 +--------------- 4 files changed, 16 insertions(+), 40 deletions(-) diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h index 678e1d38effb..0b9f0dc30d61 100644 --- a/include/linux/nsproxy.h +++ b/include/linux/nsproxy.h @@ -35,30 +35,22 @@ struct nsproxy *dup_namespaces(struct nsproxy *orig); int copy_namespaces(int flags, struct task_struct *tsk); void get_task_namespaces(struct task_struct *tsk); void free_nsproxy(struct nsproxy *ns); -struct nsproxy *put_nsproxy(struct nsproxy *ns); -static inline void finalize_put_nsproxy(struct nsproxy *ns) +static inline void put_nsproxy(struct nsproxy *ns) { - if (ns) + if (atomic_dec_and_test(&ns->count)) { free_nsproxy(ns); + } } -static inline void put_and_finalize_nsproxy(struct nsproxy *ns) +static inline void exit_task_namespaces(struct task_struct *p) { - finalize_put_nsproxy(put_nsproxy(ns)); -} - -static inline struct nsproxy *preexit_task_namespaces(struct task_struct *p) -{ - return put_nsproxy(p->nsproxy); -} - -static inline void exit_task_namespaces(struct task_struct *p, - struct nsproxy *ns) -{ - task_lock(p); - p->nsproxy = NULL; - task_unlock(p); - finalize_put_nsproxy(ns); + struct nsproxy *ns = p->nsproxy; + if (ns) { + task_lock(p); + p->nsproxy = NULL; + task_unlock(p); + put_nsproxy(ns); + } } #endif diff --git a/kernel/exit.c b/kernel/exit.c index a5bf5329ff97..35401720635b 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -396,7 +396,7 @@ void daemonize(const char *name, ...) current->fs = fs; atomic_inc(&fs->count); - put_and_finalize_nsproxy(current->nsproxy); + exit_task_namespaces(current); current->nsproxy = init_task.nsproxy; get_task_namespaces(current); @@ -853,7 +853,6 @@ static void exit_notify(struct task_struct *tsk) fastcall NORET_TYPE void do_exit(long code) { struct task_struct *tsk = current; - struct nsproxy *ns; int group_dead; profile_task_exit(tsk); @@ -939,9 +938,8 @@ fastcall NORET_TYPE void do_exit(long code) tsk->exit_code = code; proc_exit_connector(tsk); - ns = preexit_task_namespaces(tsk); exit_notify(tsk); - exit_task_namespaces(tsk, ns); + exit_task_namespaces(tsk); #ifdef CONFIG_NUMA mpol_free(tsk->mempolicy); tsk->mempolicy = NULL; diff --git a/kernel/fork.c b/kernel/fork.c index 4cf868458f06..fc723e595cd5 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1265,7 +1265,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, return p; bad_fork_cleanup_namespaces: - put_and_finalize_nsproxy(p->nsproxy); + exit_task_namespaces(p); bad_fork_cleanup_keys: exit_keys(p); bad_fork_cleanup_mm: @@ -1711,7 +1711,7 @@ asmlinkage long sys_unshare(unsigned long unshare_flags) } if (new_nsproxy) - put_and_finalize_nsproxy(new_nsproxy); + put_nsproxy(new_nsproxy); bad_unshare_cleanup_ipc: if (new_ipc) diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index 7b05bce75cde..f5b9ee6f6bbb 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -117,7 +117,7 @@ int copy_namespaces(int flags, struct task_struct *tsk) goto out_pid; out: - put_and_finalize_nsproxy(old_ns); + put_nsproxy(old_ns); return err; out_pid: @@ -135,20 +135,6 @@ out_ns: goto out; } -struct nsproxy *put_nsproxy(struct nsproxy *ns) -{ - if (ns) { - if (atomic_dec_and_test(&ns->count)) { - if (ns->mnt_ns) { - put_mnt_ns(ns->mnt_ns); - ns->mnt_ns = NULL; - } - return ns; - } - } - return NULL; -} - void free_nsproxy(struct nsproxy *ns) { if (ns->mnt_ns) -- 2.30.2