From 72fd4a35a824331d7a0f4168d7576502d95d34b3 Mon Sep 17 00:00:00 2001 From: "Robert P. J. Day" Date: Sat, 10 Feb 2007 01:45:59 -0800 Subject: [PATCH] Numerous fixes to kernel-doc info in source files. A variety of (mostly) innocuous fixes to the embedded kernel-doc content in source files, including: * make multi-line initial descriptions single line * denote some function names, constants and structs as such * change erroneous opening '/*' to '/**' in a few places * reword some text for clarity Signed-off-by: Robert P. J. Day Cc: "Randy.Dunlap" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/exit.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel/exit.c') diff --git a/kernel/exit.c b/kernel/exit.c index fec12eb12471..bc71fdfcd8a7 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -257,8 +257,7 @@ static int has_stopped_jobs(int pgrp) } /** - * reparent_to_init - Reparent the calling kernel thread to the init task - * of the pid space that the thread belongs to. + * reparent_to_init - Reparent the calling kernel thread to the init task of the pid space that the thread belongs to. * * If a kernel thread is launched as a result of a system call, or if * it ever exits, it should generally reparent itself to init so that -- cgit v1.2.3 From 944be0b224724fcbf63c3a3fe3a5478c325a6547 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 12 Feb 2007 00:52:26 -0800 Subject: [PATCH] close_files(): add scheduling point close_files() can sometimes take long enough to trigger the soft lockup detector. Cc: Eric Dumazet Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/exit.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel/exit.c') diff --git a/kernel/exit.c b/kernel/exit.c index bc71fdfcd8a7..14f17033f563 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -430,8 +430,10 @@ static void close_files(struct files_struct * files) while (set) { if (set & 1) { struct file * file = xchg(&fdt->fd[i], NULL); - if (file) + if (file) { filp_close(file, files); + cond_resched(); + } } i++; set >>= 1; -- cgit v1.2.3 From 04a2e6a5cbf84e85fe86de0a18f6509b147e1d89 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 12 Feb 2007 00:52:56 -0800 Subject: [PATCH] pid: make session_of_pgrp use struct pid instead of pid_t To properly implement a pid namespace I need to deal exclusively in terms of struct pid, because pid_t values become ambiguous. To this end session_of_pgrp is transformed to take and return a struct pid pointer. To avoid the need to worry about reference counting I now require my caller to hold the appropriate locks. Leaving callers repsonsible for increasing the reference count if they need access to the result outside of the locks. Since session_of_pgrp currently only has one caller and that caller simply uses only test the result for equality with another process group, the locking change means I don't actually have to acquire the tasklist_lock at all. tiocspgrp is also modified to take and release the lock. The logic there is a little more complicated but nothing I won't need when I convert pgrp of a tty to a struct pid pointer. Signed-off-by: Eric W. Biederman Cc: Alan Cox Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/tty_io.c | 24 +++++++++++++++++------- include/linux/kernel.h | 3 ++- kernel/exit.c | 16 +++++++--------- 3 files changed, 26 insertions(+), 17 deletions(-) (limited to 'kernel/exit.c') diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index abfe24d28c51..95f3596189cf 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -2990,7 +2990,8 @@ static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) { - pid_t pgrp; + struct pid *pgrp; + pid_t pgrp_nr; int retval = tty_check_change(real_tty); if (retval == -EIO) @@ -3001,14 +3002,23 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t (current->signal->tty != real_tty) || (real_tty->session != process_session(current))) return -ENOTTY; - if (get_user(pgrp, p)) + if (get_user(pgrp_nr, p)) return -EFAULT; - if (pgrp < 0) + if (pgrp_nr < 0) return -EINVAL; - if (session_of_pgrp(pgrp) != process_session(current)) - return -EPERM; - real_tty->pgrp = pgrp; - return 0; + rcu_read_lock(); + pgrp = find_pid(pgrp_nr); + retval = -ESRCH; + if (!pgrp) + goto out_unlock; + retval = -EPERM; + if (session_of_pgrp(pgrp) != task_session(current)) + goto out_unlock; + retval = 0; + real_tty->pgrp = pgrp_nr; +out_unlock: + rcu_read_unlock(); + return retval; } /** diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3531764318f2..9ddf25c21538 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -134,7 +134,8 @@ extern unsigned long long memparse(char *ptr, char **retptr); extern int core_kernel_text(unsigned long addr); extern int __kernel_text_address(unsigned long addr); extern int kernel_text_address(unsigned long addr); -extern int session_of_pgrp(int pgrp); +struct pid; +extern struct pid *session_of_pgrp(struct pid *pgrp); extern void dump_thread(struct pt_regs *regs, struct user *dump); diff --git a/kernel/exit.c b/kernel/exit.c index 14f17033f563..3ac6a7a6f857 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -185,21 +185,19 @@ repeat: * This checks not only the pgrp, but falls back on the pid if no * satisfactory pgrp is found. I dunno - gdb doesn't work correctly * without this... + * + * The caller must hold rcu lock or the tasklist lock. */ -int session_of_pgrp(int pgrp) +struct pid *session_of_pgrp(struct pid *pgrp) { struct task_struct *p; - int sid = 0; - - read_lock(&tasklist_lock); + struct pid *sid = NULL; - p = find_task_by_pid_type(PIDTYPE_PGID, pgrp); + p = pid_task(pgrp, PIDTYPE_PGID); if (p == NULL) - p = find_task_by_pid(pgrp); + p = pid_task(pgrp, PIDTYPE_PID); if (p != NULL) - sid = process_session(p); - - read_unlock(&tasklist_lock); + sid = task_session(p); return sid; } -- cgit v1.2.3 From 0475ac0845f9295bc5f69af45f58dff2c104c8d1 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 12 Feb 2007 00:52:57 -0800 Subject: [PATCH] pid: use struct pid for talking about process groups in exitc Modify has_stopped_jobs and will_become_orphan_pgrp to use struct pid based process groups. This reduces the number of hash tables looks ups and paves the way for multiple pid spaces. Signed-off-by: Eric W. Biederman Cc: Alan Cox Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/exit.c | 42 ++++++++++++++++++++++-------------------- 1 file changed, 22 insertions(+), 20 deletions(-) (limited to 'kernel/exit.c') diff --git a/kernel/exit.c b/kernel/exit.c index 3ac6a7a6f857..407b80aaefda 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -210,22 +210,22 @@ struct pid *session_of_pgrp(struct pid *pgrp) * * "I ask you, have you ever known what it is to be an orphan?" */ -static int will_become_orphaned_pgrp(int pgrp, struct task_struct *ignored_task) +static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task) { struct task_struct *p; int ret = 1; - do_each_task_pid(pgrp, PIDTYPE_PGID, p) { + do_each_pid_task(pgrp, PIDTYPE_PGID, p) { if (p == ignored_task || p->exit_state || is_init(p->real_parent)) continue; - if (process_group(p->real_parent) != pgrp && - process_session(p->real_parent) == process_session(p)) { + if (task_pgrp(p->real_parent) != pgrp && + task_session(p->real_parent) == task_session(p)) { ret = 0; break; } - } while_each_task_pid(pgrp, PIDTYPE_PGID, p); + } while_each_pid_task(pgrp, PIDTYPE_PGID, p); return ret; /* (sighing) "Often!" */ } @@ -234,23 +234,23 @@ int is_orphaned_pgrp(int pgrp) int retval; read_lock(&tasklist_lock); - retval = will_become_orphaned_pgrp(pgrp, NULL); + retval = will_become_orphaned_pgrp(find_pid(pgrp), NULL); read_unlock(&tasklist_lock); return retval; } -static int has_stopped_jobs(int pgrp) +static int has_stopped_jobs(struct pid *pgrp) { int retval = 0; struct task_struct *p; - do_each_task_pid(pgrp, PIDTYPE_PGID, p) { + do_each_pid_task(pgrp, PIDTYPE_PGID, p) { if (p->state != TASK_STOPPED) continue; retval = 1; break; - } while_each_task_pid(pgrp, PIDTYPE_PGID, p); + } while_each_pid_task(pgrp, PIDTYPE_PGID, p); return retval; } @@ -648,14 +648,14 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced) * than we are, and it was the only connection * outside, so the child pgrp is now orphaned. */ - if ((process_group(p) != process_group(father)) && - (process_session(p) == process_session(father))) { - int pgrp = process_group(p); + if ((task_pgrp(p) != task_pgrp(father)) && + (task_session(p) == task_session(father))) { + struct pid *pgrp = task_pgrp(p); if (will_become_orphaned_pgrp(pgrp, NULL) && has_stopped_jobs(pgrp)) { - __kill_pg_info(SIGHUP, SEND_SIG_PRIV, pgrp); - __kill_pg_info(SIGCONT, SEND_SIG_PRIV, pgrp); + __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp); + __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp); } } } @@ -735,6 +735,7 @@ static void exit_notify(struct task_struct *tsk) int state; struct task_struct *t; struct list_head ptrace_dead, *_p, *_n; + struct pid *pgrp; if (signal_pending(tsk) && !(tsk->signal->flags & SIGNAL_GROUP_EXIT) && !thread_group_empty(tsk)) { @@ -787,12 +788,13 @@ static void exit_notify(struct task_struct *tsk) t = tsk->real_parent; - if ((process_group(t) != process_group(tsk)) && - (process_session(t) == process_session(tsk)) && - will_become_orphaned_pgrp(process_group(tsk), tsk) && - has_stopped_jobs(process_group(tsk))) { - __kill_pg_info(SIGHUP, SEND_SIG_PRIV, process_group(tsk)); - __kill_pg_info(SIGCONT, SEND_SIG_PRIV, process_group(tsk)); + pgrp = task_pgrp(tsk); + if ((task_pgrp(t) != pgrp) && + (task_session(t) != task_session(tsk)) && + will_become_orphaned_pgrp(pgrp, tsk) && + has_stopped_jobs(pgrp)) { + __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp); + __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp); } /* Let father know we died -- cgit v1.2.3 From 3e7cd6c413c9e6fbb5e1ee2acdadb4ababd2d474 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 12 Feb 2007 00:52:58 -0800 Subject: [PATCH] pid: replace is_orphaned_pgrp with is_current_pgrp_orphaned Every call to is_orphaned_pgrp passed in process_group(current) which is racy with respect to another thread changing our process group. It didn't bite us because we were dealing with integers and the worse we would get would be a stale answer. In switching the checks to use struct pid to be a little more efficient and prepare the way for pid namespaces this race became apparent. So I simplified the calls to the more specialized is_current_pgrp_orphaned so I didn't have to worry about making logic changes to avoid the race. Signed-off-by: Eric W. Biederman Cc: Alan Cox Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/n_tty.c | 2 +- drivers/char/tty_io.c | 2 +- include/linux/tty.h | 2 +- kernel/exit.c | 4 ++-- kernel/signal.c | 2 +- 5 files changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel/exit.c') diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c index 2bdb0144a22e..c035c2f1f462 100644 --- a/drivers/char/n_tty.c +++ b/drivers/char/n_tty.c @@ -1188,7 +1188,7 @@ static int job_control(struct tty_struct *tty, struct file *file) printk("read_chan: tty->pgrp <= 0!\n"); else if (process_group(current) != tty->pgrp) { if (is_ignored(SIGTTIN) || - is_orphaned_pgrp(process_group(current))) + is_current_pgrp_orphaned()) return -EIO; kill_pg(process_group(current), SIGTTIN, 1); return -ERESTARTSYS; diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 95f3596189cf..94070f7bf389 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -1118,7 +1118,7 @@ int tty_check_change(struct tty_struct * tty) return 0; if (is_ignored(SIGTTOU)) return 0; - if (is_orphaned_pgrp(process_group(current))) + if (is_current_pgrp_orphaned()) return -EIO; (void) kill_pg(process_group(current), SIGTTOU, 1); return -ERESTARTSYS; diff --git a/include/linux/tty.h b/include/linux/tty.h index 0a10a4e7bbc3..d0e03c4a71b1 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -303,7 +303,7 @@ extern int tty_read_raw_data(struct tty_struct *tty, unsigned char *bufp, int buflen); extern void tty_write_message(struct tty_struct *tty, char *msg); -extern int is_orphaned_pgrp(int pgrp); +extern int is_current_pgrp_orphaned(void); extern int is_ignored(int sig); extern int tty_signal(int sig, struct tty_struct *tty); extern void tty_hangup(struct tty_struct * tty); diff --git a/kernel/exit.c b/kernel/exit.c index 407b80aaefda..f132349c0325 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -229,12 +229,12 @@ static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignor return ret; /* (sighing) "Often!" */ } -int is_orphaned_pgrp(int pgrp) +int is_current_pgrp_orphaned(void) { int retval; read_lock(&tasklist_lock); - retval = will_become_orphaned_pgrp(find_pid(pgrp), NULL); + retval = will_become_orphaned_pgrp(task_pgrp(current), NULL); read_unlock(&tasklist_lock); return retval; diff --git a/kernel/signal.c b/kernel/signal.c index de66def71644..a9b679ed795c 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1909,7 +1909,7 @@ relock: /* signals can be posted during this window */ - if (is_orphaned_pgrp(process_group(current))) + if (is_current_pgrp_orphaned()) goto relock; spin_lock_irq(¤t->sighand->siglock); -- cgit v1.2.3