user/sven/linux.git/kernel/exit.c, branch v3.10.44

exit: call disassociate_ctty() before exit_task_namespaces()

2014-04-27T00:15:36Z

commit c39df5fa37b0623589508c95515b4aa1531c524e upstream. Commit 8aac62706ada ("move exit_task_namespaces() outside of exit_notify()") breaks pppd and the exiting service crashes the kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 IP: ppp_register_channel+0x13/0x20 [ppp_generic] Call Trace: ppp_asynctty_open+0x12b/0x170 [ppp_async] tty_ldisc_open.isra.2+0x27/0x60 tty_ldisc_hangup+0x1e3/0x220 __tty_hangup+0x2c4/0x440 disassociate_ctty+0x61/0x270 do_exit+0x7f2/0xa50 ppp_register_channel() needs ->net_ns and current->nsproxy == NULL. Move disassociate_ctty() before exit_task_namespaces(), it doesn't make sense to delay it after perf_event_exit_task() or cgroup_exit(). This also allows to use task_work_add() inside the (nontrivial) code paths in disassociate_ctty(). Investigated by Peter Hurley. Signed-off-by: Oleg Nesterov Reported-by: Sree Harsha Totakura Cc: Peter Hurley Cc: Sree Harsha Totakura Cc: "Eric W. Biederman" Cc: Jeff Dike Cc: Ingo Molnar Cc: Andrey Vagin Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

wait: fix reparent_leader() vs EXIT_DEAD->EXIT_ZOMBIE race

2014-04-27T00:15:36Z

commit dfccbb5e49a621c1b21a62527d61fc4305617aca upstream. wait_task_zombie() first does EXIT_ZOMBIE->EXIT_DEAD transition and drops tasklist_lock. If this task is not the natural child and it is traced, we change its state back to EXIT_ZOMBIE for ->real_parent. The last transition is racy, this is even documented in 50b8d257486a "ptrace: partially fix the do_wait(WEXITED) vs EXIT_DEAD->EXIT_ZOMBIE race". wait_consider_task() tries to detect this transition and clear ->notask_error but we can't rely on ptrace_reparented(), debugger can exit and do ptrace_unlink() before its sub-thread sets EXIT_ZOMBIE. And there is another problem which were missed before: this transition can also race with reparent_leader() which doesn't reset >exit_signal if EXIT_DEAD, assuming that this task must be reaped by someone else. So the tracee can be re-parented with ->exit_signal != SIGCHLD, and if /sbin/init doesn't use __WALL it becomes unreapable. Change reparent_leader() to update ->exit_signal even if EXIT_DEAD. Note: this is the simple temporary hack for -stable, it doesn't try to solve all problems, it will be reverted by the next changes. Signed-off-by: Oleg Nesterov Reported-by: Jan Kratochvil Reported-by: Michal Schmidt Tested-by: Michal Schmidt Cc: Al Viro Cc: Lennart Poettering Cc: Roland McGrath Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

move exit_task_namespaces() outside of exit_notify()

2013-06-15T01:39:08Z

exit_notify() does exit_task_namespaces() after forget_original_parent(). This was needed to ensure that ->nsproxy can't be cleared prematurely, an exiting child we are going to reparent can do do_notify_parent() and use the parent's (ours) pid_ns. However, after 32084504 "pidns: use task_active_pid_ns in do_notify_parent" ->nsproxy != NULL is no longer needed, we rely on task_active_pid_ns(). Move exit_task_namespaces() from exit_notify() to do_exit(), after exit_fs() and before exit_task_work(). This solves the problem reported by Andrey, free_ipc_ns()->shm_destroy() does fput() which needs task_work_add(). Note: this particular problem can be fixed if we change fput(), and that change makes sense anyway. But there is another reason to move the callsite. The original reason for exit_task_namespaces() from the middle of exit_notify() was subtle and it has already gone away, now this looks confusing. And this allows us do simplify exit_notify(), we can avoid unlock/lock(tasklist) and we can use ->exit_state instead of PF_EXITING in forget_original_parent(). Reported-by: Andrey Vagin Signed-off-by: Oleg Nesterov Acked-by: "Eric W. Biederman" Acked-by: Andrey Vagin Signed-off-by: Al Viro

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-05-02T00:51:54Z

Pull VFS updates from Al Viro, Misc cleanups all over the place, mainly wrt /proc interfaces (switch create_proc_entry to proc_create(), get rid of the deprecated create_proc_read_entry() in favor of using proc_create_data() and seq_file etc). 7kloc removed. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits) don't bother with deferred freeing of fdtables proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h proc: Make the PROC_I() and PDE() macros internal to procfs proc: Supply a function to remove a proc entry by PDE take cgroup_open() and cpuset_open() to fs/proc/base.c ppc: Clean up scanlog ppc: Clean up rtas_flash driver somewhat hostap: proc: Use remove_proc_subtree() drm: proc: Use remove_proc_subtree() drm: proc: Use minor->index to label things, not PDE->name drm: Constify drm_proc_list[] zoran: Don't print proc_dir_entry data in debug reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show() proc: Supply an accessor for getting the data from a PDE's parent airo: Use remove_proc_subtree() rtl8192u: Don't need to save device proc dir PDE rtl8187se: Use a dir under /proc/net/r8180/ proc: Add proc_mkdir_data() proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h} proc: Move PDE_NET() to fs/proc/proc_net.c ...

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

2013-05-01T14:21:43Z

Pull compat cleanup from Al Viro: "Mostly about syscall wrappers this time; there will be another pile with patches in the same general area from various people, but I'd rather push those after both that and vfs.git pile are in." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: syscalls.h: slightly reduce the jungles of macros get rid of union semop in sys_semctl(2) arguments make do_mremap() static sparc: no need to sign-extend in sync_file_range() wrapper ppc compat wrappers for add_key(2) and request_key(2) are pointless x86: trim sys_ia32.h x86: sys32_kill and sys32_mprotect are pointless get rid of compat_sys_semctl() and friends in case of ARCH_WANT_OLD_COMPAT_IPC merge compat sys_ipc instances consolidate compat lookup_dcookie() convert vmsplice to COMPAT_SYSCALL_DEFINE switch getrusage() to COMPAT_SYSCALL_DEFINE switch epoll_pwait to COMPAT_SYSCALL_DEFINE convert sendfile{,64} to COMPAT_SYSCALL_DEFINE switch signalfd{,4}() to COMPAT_SYSCALL_DEFINE make SYSCALL_DEFINE-generated wrappers do asmlinkage_protect make HAVE_SYSCALL_WRAPPERS unconditional consolidate cond_syscall and SYSCALL_ALIAS declarations teach SYSCALL_DEFINE how to deal with long long/unsigned long long get rid of duplicate logics in __SC_....[1-6] definitions

get rid of the last free_pipe_info() callers

2013-04-09T18:13:02Z

and rename __free_pipe_info() to free_pipe_info() Signed-off-by: Al Viro

Revert "lockdep: check that no locks held at freeze time"

2013-03-31T18:38:33Z

This reverts commit 6aa9707099c4b25700940eb3d016f16c4434360d. Commit 6aa9707099c4 ("lockdep: check that no locks held at freeze time") causes problems with NFS root filesystems. The failures were noticed on OMAP2 and 3 boards during kernel init: [ BUG: swapper/0/1 still has locks held! ] 3.9.0-rc3-00344-ga937536 #1 Not tainted ------------------------------------- 1 lock held by swapper/0/1: #0: (&type->s_umount_key#13/1){+.+.+.}, at: [] sget+0x248/0x574 stack backtrace: rpc_wait_bit_killable __wait_on_bit out_of_line_wait_on_bit __rpc_execute rpc_run_task rpc_call_sync nfs_proc_get_root nfs_get_root nfs_fs_mount_common nfs_try_mount nfs_fs_mount mount_fs vfs_kern_mount do_mount sys_mount do_mount_root mount_root prepare_namespace kernel_init_freeable kernel_init Although the rootfs mounts, the system is unstable. Here's a transcript from a PM test: http://www.pwsan.com/omap/testlogs/test_v3.9-rc3/20130317194234/pm/37xxevm/37xxevm_log.txt Here's what the test log should look like: http://www.pwsan.com/omap/testlogs/test_v3.8/20130218214403/pm/37xxevm/37xxevm_log.txt Mailing list discussion is here: http://lkml.org/lkml/2013/3/4/221 Deal with this for v3.9 by reverting the problem commit, until folks can figure out the right long-term course of action. Signed-off-by: Paul Walmsley Cc: Mandeep Singh Baines Cc: Jeff Layton Cc: Shawn Guo Cc: Cc: Fengguang Wu Cc: Trond Myklebust Cc: Ingo Molnar Cc: Ben Chan Cc: Oleg Nesterov Cc: Tejun Heo Cc: Rafael J. Wysocki Cc: Andrew Morton Signed-off-by: Linus Torvalds

make SYSCALL_DEFINE-generated wrappers do asmlinkage_protect

2013-03-04T03:58:33Z

... and switch i386 to HAVE_SYSCALL_WRAPPERS, killing open-coded uses of asmlinkage_protect() in a bunch of syscalls. Signed-off-by: Al Viro

coredump: use a freezable_schedule for the coredump_finish wait

2013-02-28T03:10:11Z

Prevents hung_task detector from panicing the machine. This is also needed to prevent this wait from blocking suspend. (It doesnt' currently block suspend but it would once the next patch in this series is applied.) [yongjun_wei@trendmicro.com.cn: kernel/exit.c: remove duplicated include] Signed-off-by: Mandeep Singh Baines Cc: Ben Chan Cc: Oleg Nesterov Cc: Tejun Heo Cc: Rafael J. Wysocki Cc: Ingo Molnar Signed-off-by: Wei Yongjun Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lockdep: check that no locks held at freeze time

2013-02-28T03:10:11Z

We shouldn't try_to_freeze if locks are held. Holding a lock can cause a deadlock if the lock is later acquired in the suspend or hibernate path (e.g. by dpm). Holding a lock can also cause a deadlock in the case of cgroup_freezer if a lock is held inside a frozen cgroup that is later acquired by a process outside that group. [akpm@linux-foundation.org: export debug_check_no_locks_held] Signed-off-by: Mandeep Singh Baines Cc: Ben Chan Cc: Oleg Nesterov Cc: Tejun Heo Cc: Rafael J. Wysocki Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds