Merge tag 'x86_mm_for_6.2_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

[linux-block.git] / kernel / fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index 6142c588c18ae5bb5dd56a46a25cb3c547721844..9f7fe354189785c2cb72f74568536a86fd898fce 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -75,7 +75,6 @@
 #include <linux/freezer.h>
 #include <linux/delayacct.h>
 #include <linux/taskstats_kern.h>
-#include <linux/random.h>
 #include <linux/tty.h>
 #include <linux/fs_struct.h>
 #include <linux/magic.h>
@@ -97,6 +96,7 @@
 #include <linux/scs.h>
 #include <linux/io_uring.h>
 #include <linux/bpf.h>
+#include <linux/stackprotector.h>
 
 #include <asm/pgalloc.h>
 #include <linux/uaccess.h>
@@ -535,6 +535,9 @@ void put_task_stack(struct task_struct *tsk)
 
 void free_task(struct task_struct *tsk)
 {
+#ifdef CONFIG_SECCOMP
+       WARN_ON_ONCE(tsk->seccomp.filter);
+#endif
        release_user_cpus_ptr(tsk);
        scs_release(tsk);
 
@@ -753,8 +756,13 @@ static void check_mm(struct mm_struct *mm)
                         "Please make sure 'struct resident_page_types[]' is updated as well");
 
        for (i = 0; i < NR_MM_COUNTERS; i++) {
-               long x = atomic_long_read(&mm->rss_stat.count[i]);
+               long x = percpu_counter_sum(&mm->rss_stat[i]);
+
+               if (likely(!x))
+                       continue;
 
+               /* Making sure this is not due to race with CPU offlining. */
+               x = percpu_counter_sum_all(&mm->rss_stat[i]);
                if (unlikely(x))
                        pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld\n",
                                 mm, resident_page_types[i], x);
@@ -779,6 +787,8 @@ static void check_mm(struct mm_struct *mm)
  */
 void __mmdrop(struct mm_struct *mm)
 {
+       int i;
+
        BUG_ON(mm == &init_mm);
        WARN_ON_ONCE(mm == current->mm);
        WARN_ON_ONCE(mm == current->active_mm);
@@ -788,6 +798,9 @@ void __mmdrop(struct mm_struct *mm)
        check_mm(mm);
        put_user_ns(mm->user_ns);
        mm_pasid_drop(mm);
+
+       for (i = 0; i < NR_MM_COUNTERS; i++)
+               percpu_counter_destroy(&mm->rss_stat[i]);
        free_mm(mm);
 }
 EXPORT_SYMBOL_GPL(__mmdrop);
@@ -1107,6 +1120,8 @@ static void mm_init_uprobes_state(struct mm_struct *mm)
 static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
        struct user_namespace *user_ns)
 {
+       int i;
+
        mt_init_flags(&mm->mm_mt, MM_MT_FLAGS);
        mt_set_external_lock(&mm->mm_mt, &mm->mmap_lock);
        atomic_set(&mm->mm_users, 1);
@@ -1148,10 +1163,17 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
        if (init_new_context(p, mm))
                goto fail_nocontext;
 
+       for (i = 0; i < NR_MM_COUNTERS; i++)
+               if (percpu_counter_init(&mm->rss_stat[i], 0, GFP_KERNEL_ACCOUNT))
+                       goto fail_pcpu;
+
        mm->user_ns = get_user_ns(user_ns);
        lru_gen_init_mm(mm);
        return mm;
 
+fail_pcpu:
+       while (i > 0)
+               percpu_counter_destroy(&mm->rss_stat[--i]);
 fail_nocontext:
        mm_free_pgd(mm);
 fail_nopgd:
@@ -2043,15 +2065,6 @@ static __latent_entropy struct task_struct *copy_process(
                        return ERR_PTR(-EINVAL);
        }
 
-       /*
-        * If the new process will be in a different time namespace
-        * do not allow it to share VM or a thread group with the forking task.
-        */
-       if (clone_flags & (CLONE_THREAD | CLONE_VM)) {
-               if (nsp->time_ns != nsp->time_ns_for_children)
-                       return ERR_PTR(-EINVAL);
-       }
-
        if (clone_flags & CLONE_PIDFD) {
                /*
                 * - CLONE_DETACHED is blocked so that we can potentially
@@ -2406,12 +2419,6 @@ static __latent_entropy struct task_struct *copy_process(
 
        spin_lock(&current->sighand->siglock);
 
-       /*
-        * Copy seccomp details explicitly here, in case they were changed
-        * before holding sighand lock.
-        */
-       copy_seccomp(p);
-
        rv_task_fork(p);
 
        rseq_fork(p, clone_flags);
@@ -2428,6 +2435,14 @@ static __latent_entropy struct task_struct *copy_process(
                goto bad_fork_cancel_cgroup;
        }
 
+       /* No more failure paths after this point. */
+
+       /*
+        * Copy seccomp details explicitly here, in case they were changed
+        * before holding sighand lock.
+        */
+       copy_seccomp(p);
+
        init_task_pid_links(p);
        if (likely(p->pid)) {
                ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);