From 6a61671bb2f3a1bd12cd17b8fca811a624782632 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 16 Dec 2012 20:00:34 +0100 Subject: cputime: Safely read cputime of full dynticks CPUs While remotely reading the cputime of a task running in a full dynticks CPU, the values stored in utime/stime fields of struct task_struct may be stale. Its values may be those of the last kernel <-> user transition time snapshot and we need to add the tickless time spent since this snapshot. To fix this, flush the cputime of the dynticks CPUs on kernel <-> user transition and record the time / context where we did this. Then on top of this snapshot and the current time, perform the fixup on the reader side from task_times() accessors. Signed-off-by: Frederic Weisbecker Cc: Andrew Morton Cc: Ingo Molnar Cc: Li Zhong Cc: Namhyung Kim Cc: Paul E. McKenney Cc: Paul Gortmaker Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner [fixed kvm module related build errors] Signed-off-by: Sedat Dilek --- kernel/fork.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel/fork.c') diff --git a/kernel/fork.c b/kernel/fork.c index 65ca6d27f24e..e68a95b4cf26 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1233,6 +1233,12 @@ static struct task_struct *copy_process(unsigned long clone_flags, #ifndef CONFIG_VIRT_CPU_ACCOUNTING p->prev_cputime.utime = p->prev_cputime.stime = 0; #endif +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN + seqlock_init(&p->vtime_seqlock); + p->vtime_snap = 0; + p->vtime_snap_whence = VTIME_SLEEPING; +#endif + #if defined(SPLIT_RSS_COUNTING) memset(&p->rss_stat, 0, sizeof(p->rss_stat)); #endif -- cgit v1.2.3 From 496ad9aa8ef448058e36ca7a787c61f2e63f0f54 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 23 Jan 2013 17:07:38 -0500 Subject: new helper: file_inode(file) Signed-off-by: Al Viro --- kernel/fork.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/fork.c') diff --git a/kernel/fork.c b/kernel/fork.c index c535f33bbb9c..4ff724f81f25 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -413,7 +413,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) tmp->vm_next = tmp->vm_prev = NULL; file = tmp->vm_file; if (file) { - struct inode *inode = file->f_path.dentry->d_inode; + struct inode *inode = file_inode(file); struct address_space *mapping = file->f_mapping; get_file(file); -- cgit v1.2.3 From 6f977e6b2f75fdaccfd9be82bbf72fe5c60e8807 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Wed, 27 Feb 2013 17:03:23 -0800 Subject: fork: unshare: remove dead code If new_nsproxy is set we will always call switch_task_namespaces and then set new_nsproxy back to NULL so the reassignment and fall through check are redundant Signed-off-by: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'kernel/fork.c') diff --git a/kernel/fork.c b/kernel/fork.c index 8f62b2a0f120..8d932b1c9056 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1861,10 +1861,8 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) exit_sem(current); } - if (new_nsproxy) { + if (new_nsproxy) switch_task_namespaces(current, new_nsproxy); - new_nsproxy = NULL; - } task_lock(current); @@ -1894,9 +1892,6 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) } } - if (new_nsproxy) - put_nsproxy(new_nsproxy); - bad_unshare_cleanup_cred: if (new_cred) put_cred(new_cred); -- cgit v1.2.3 From e66eded8309ebf679d3d3c1f5820d1f2ca332c71 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 13 Mar 2013 11:51:49 -0700 Subject: userns: Don't allow CLONE_NEWUSER | CLONE_FS Don't allowing sharing the root directory with processes in a different user namespace. There doesn't seem to be any point, and to allow it would require the overhead of putting a user namespace reference in fs_struct (for permission checks) and incrementing that reference count on practically every call to fork. So just perform the inexpensive test of forbidding sharing fs_struct acrosss processes in different user namespaces. We already disallow other forms of threading when unsharing a user namespace so this should be no real burden in practice. This updates setns, clone, and unshare to disallow multiple user namespaces sharing an fs_struct. Cc: stable@vger.kernel.org Signed-off-by: "Eric W. Biederman" Signed-off-by: Linus Torvalds --- kernel/fork.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'kernel/fork.c') diff --git a/kernel/fork.c b/kernel/fork.c index 8d932b1c9056..1766d324d5e3 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1141,6 +1141,9 @@ static struct task_struct *copy_process(unsigned long clone_flags, if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) return ERR_PTR(-EINVAL); + if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS)) + return ERR_PTR(-EINVAL); + /* * Thread groups must share signals as well, and detached threads * can only be started up within the thread group. @@ -1807,7 +1810,7 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) * If unsharing a user namespace must also unshare the thread. */ if (unshare_flags & CLONE_NEWUSER) - unshare_flags |= CLONE_THREAD; + unshare_flags |= CLONE_THREAD | CLONE_FS; /* * If unsharing a pid namespace must also unshare the thread. */ -- cgit v1.2.3