linux/kernel/exit.c, branch v2.6.24

wait_task_stopped(): pass correct exit_code to wait_noreap_copyout()

2007-11-29T17:24:55Z

In wait_task_stopped() exit_code already contains the right value for the si_status member of siginfo, and this is simply set in the non WNOWAIT case. If you call waitid() with a stopped or traced process, you'll get the signal in siginfo.si_status as expected -- however if you call waitid(WNOWAIT) at the same time, you'll get the signal << 8 | 0x7f Pass it unchanged to wait_noreap_copyout(); we would only need to shift it and add 0x7f if we were returning it in the user status field and that isn't used for any function that permits WNOWAIT. Signed-off-by: Scott James Remnant Signed-off-by: Oleg Nesterov Cc: Roland McGrath Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

wait_task_stopped(): don't use task_pid_nr_ns() lockless

2007-11-29T17:24:52Z

wait_task_stopped(WNOWAIT) does task_pid_nr_ns() without tasklist/rcu lock, we can read an already freed memory. Use the cached pid_t value. Signed-off-by: Oleg Nesterov Looks-good-to: Roland McGrath Acked-by: Pavel Emelyanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

wait_task_stopped: Check p->exit_state instead of TASK_TRACED

2007-11-15T16:36:27Z

The original meaning of the old test (p->state > TASK_STOPPED) was "not dead", since it was before TASK_TRACED existed and before the state/exit_state split. It was a wrong correction in commit 14bf01bb0599c89fc7f426d20353b76e12555308 to make this test for TASK_TRACED instead. It should have been changed when TASK_TRACED was introducted and again when exit_state was introduced. Signed-off-by: Roland McGrath Cc: Oleg Nesterov Cc: Alexey Dobriyan Cc: Kees Cook Acked-by: Scott James Remnant Signed-off-by: Linus Torvalds

Uninline fork.c/exit.c

2007-10-19T18:53:56Z

Save ~650 bytes here. add/remove: 4/0 grow/shrink: 0/7 up/down: 430/-1088 (-658) function old new delta __copy_fs_struct - 202 +202 __put_fs_struct - 112 +112 __exit_fs - 58 +58 __exit_files - 58 +58 exit_files 58 2 -56 put_fs_struct 112 5 -107 exit_fs 161 2 -159 sys_unshare 774 590 -184 copy_process 4031 3840 -191 do_exit 1791 1597 -194 copy_fs_struct 202 5 -197 No difference in lmbench lat_proc tests on 2-way Opteron 246. Smaaaal degradation on UP P4 (within errors). [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Alexey Dobriyan Cc: Arjan van de Ven Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Use helpers to obtain task pid in printks

2007-10-19T18:53:43Z

The task_struct->pid member is going to be deprecated, so start using the helpers (task_pid_nr/task_pid_vnr/task_pid_nr_ns) in the kernel. The first thing to start with is the pid, printed to dmesg - in this case we may safely use task_pid_nr(). Besides, printks produce more (much more) than a half of all the explicit pid usage. [akpm@linux-foundation.org: git-drm went and changed lots of stuff] Signed-off-by: Pavel Emelyanov Cc: Dave Airlie Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Isolate the explicit usage of signal->pgrp

2007-10-19T18:53:43Z

The pgrp field is not used widely around the kernel so it is now marked as deprecated with appropriate comment. The initialization of INIT_SIGNALS is trimmed because a) they are set to 0 automatically; b) gcc cannot properly initialize two anonymous (the second one is the one with the session) unions. In this particular case to make it compile we'd have to add some field initialized right before the .pgrp. This is the same patch as the 1ec320afdc9552c92191d5f89fcd1ebe588334ca one (from Cedric), but for the pgrp field. Some progress report: We have to deprecate the pid, tgid, session and pgrp fields on struct task_struct and struct signal_struct. The session and pgrp are already deprecated. The tgid value is close to being such - the worst known usage in in fs/locks.c and audit code. The pid field deprecation is mainly blocked by numerous printk-s around the kernel that print the tsk->pid to log. Signed-off-by: Pavel Emelyanov Cc: Oleg Nesterov Cc: Sukadev Bhattiprolu Cc: Cedric Le Goater Cc: Serge Hallyn Cc: "Eric W. Biederman" Cc: Herbert Poetzl Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pid namespaces: changes to show virtual ids to user

2007-10-19T18:53:40Z

This is the largest patch in the set. Make all (I hope) the places where the pid is shown to or get from user operate on the virtual pids. The idea is: - all in-kernel data structures must store either struct pid itself or the pid's global nr, obtained with pid_nr() call; - when seeking the task from kernel code with the stored id one should use find_task_by_pid() call that works with global pids; - when showing pid's numerical value to the user the virtual one should be used, but however when one shows task's pid outside this task's namespace the global one is to be used; - when getting the pid from userspace one need to consider this as the virtual one and use appropriate task/pid-searching functions. [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: nuther build fix] [akpm@linux-foundation.org: yet nuther build fix] [akpm@linux-foundation.org: remove unneeded casts] Signed-off-by: Pavel Emelyanov Signed-off-by: Alexey Dobriyan Cc: Sukadev Bhattiprolu Cc: Oleg Nesterov Cc: Paul Menage Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pid namespaces: destroy pid namespace on init's death

2007-10-19T18:53:40Z

Terminate all processes in a namespace when the reaper of the namespace is exiting. We do this by walking the pidmap of the namespace and sending SIGKILL to all processes. Signed-off-by: Sukadev Bhattiprolu Acked-by: Pavel Emelyanov Cc: Oleg Nesterov Cc: Sukadev Bhattiprolu Cc: Paul Menage Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pid namespaces: prepare proc_flust_task() to flush entries from multiple proc trees

2007-10-19T18:53:38Z

The first part is trivial - we just make the proc_flush_task() to operate on arbitrary vfsmount with arbitrary ids and pass the pid and global proc_mnt to it. The other change is more tricky: I moved the proc_flush_task() call in release_task() higher to address the following problem. When flushing task from many proc trees we need to know the set of ids (not just one pid) to find the dentries' names to flush. Thus we need to pass the task's pid to proc_flush_task() as struct pid is the only object that can provide all the pid numbers. But after __exit_signal() task has detached all his pids and this information is lost. This creates a tiny gap for proc_pid_lookup() to bring some dentries back to tree and keep them in hash (since pids are still alive before __exit_signal()) till the next shrink, but since proc_flush_task() does not provide a 100% guarantee that the dentries will be flushed, this is OK to do so. Signed-off-by: Pavel Emelyanov Cc: Oleg Nesterov Cc: Sukadev Bhattiprolu Cc: Paul Menage Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pid namespaces: move exit_task_namespaces()

2007-10-19T18:53:38Z

Make task release its namespaces after it has reparented all his children to child_reaper, but before it notifies its parent about its death. The reason to release namespaces after reparenting is that when task exits it may send a signal to its parent (SIGCHLD), but if the parent has already exited its namespaces there will be no way to decide what pid to dever to him - parent can be from different namespace. The reason to release namespace before notifying the parent it that when task sends a SIGCHLD to parent it can call wait() on this taks and release it. But releasing the mnt namespace implies dropping of all the mounts in the mnt namespace and NFS expects the task to have valid sighand pointer. Thanks to Oleg for pointing out some races that can apear and helping with patches and fixes. Signed-off-by: Pavel Emelyanov Cc: Oleg Nesterov Cc: Sukadev Bhattiprolu Cc: Paul Menage Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds