diff options
| author | KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> | 2010-10-27 15:34:08 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-27 18:03:12 -0700 |
| commit | 9b1bf12d5d51bca178dea21b04a0805e29d60cf1 (patch) | |
| tree | 902a2c0e5882a2152da59a589958d6426dc84643 /include | |
| parent | b84011508360d6885a9d95a235ec77d56f133377 (diff) | |
| download | lwn-9b1bf12d5d51bca178dea21b04a0805e29d60cf1.tar.gz lwn-9b1bf12d5d51bca178dea21b04a0805e29d60cf1.zip | |
signals: move cred_guard_mutex from task_struct to signal_struct
Oleg Nesterov pointed out we have to prevent multiple-threads-inside-exec
itself and we can reuse ->cred_guard_mutex for it. Yes, concurrent
execve() has no worth.
Let's move ->cred_guard_mutex from task_struct to signal_struct. It
naturally prevent multiple-threads-inside-exec.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/init_task.h | 4 | ||||
| -rw-r--r-- | include/linux/sched.h | 7 | ||||
| -rw-r--r-- | include/linux/tracehook.h | 2 |
3 files changed, 7 insertions, 6 deletions
diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 2fea6c8ef6ba..1f8c06ce0fa6 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -29,6 +29,8 @@ extern struct fs_struct init_fs; .running = 0, \ .lock = __SPIN_LOCK_UNLOCKED(sig.cputimer.lock), \ }, \ + .cred_guard_mutex = \ + __MUTEX_INITIALIZER(sig.cred_guard_mutex), \ } extern struct nsproxy init_nsproxy; @@ -145,8 +147,6 @@ extern struct cred init_cred; .group_leader = &tsk, \ RCU_INIT_POINTER(.real_cred, &init_cred), \ RCU_INIT_POINTER(.cred, &init_cred), \ - .cred_guard_mutex = \ - __MUTEX_INITIALIZER(tsk.cred_guard_mutex), \ .comm = "swapper", \ .thread = INIT_THREAD, \ .fs = &init_fs, \ diff --git a/include/linux/sched.h b/include/linux/sched.h index 3ff5c8519abd..be7adb7588e5 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -626,6 +626,10 @@ struct signal_struct { int oom_adj; /* OOM kill score adjustment (bit shift) */ int oom_score_adj; /* OOM kill score adjustment */ + + struct mutex cred_guard_mutex; /* guard against foreign influences on + * credential calculations + * (notably. ptrace) */ }; /* Context switch must be unlocked if interrupts are to be enabled */ @@ -1305,9 +1309,6 @@ struct task_struct { * credentials (COW) */ const struct cred __rcu *cred; /* effective (overridable) subjective task * credentials (COW) */ - struct mutex cred_guard_mutex; /* guard against foreign influences on - * credential calculations - * (notably. ptrace) */ struct cred *replacement_session_keyring; /* for KEYCTL_SESSION_TO_PARENT */ char comm[TASK_COMM_LEN]; /* executable name excluding path diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 10db0102a890..3a2e66d88a32 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -150,7 +150,7 @@ static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step) * * Return %LSM_UNSAFE_* bits applied to an exec because of tracing. * - * @task->cred_guard_mutex is held by the caller through the do_execve(). + * @task->signal->cred_guard_mutex is held by the caller through the do_execve(). */ static inline int tracehook_unsafe_exec(struct task_struct *task) { |