diff options
author | Xavier Boudet <x-boudet@ti.com> | 2012-11-05 14:20:49 +0100 |
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committer | Xavier Boudet <x-boudet@ti.com> | 2012-11-05 14:20:49 +0100 |
commit | 29a6cc6e3a241e34749edc3cc69cf88757acd491 (patch) | |
tree | 6a0efb8175f50c183e0541cbb1b1f8c2d3979493 /kernel | |
parent | 3374c3584e1cb313f62b6a13418e477625c4a25e (diff) | |
parent | 5390967b2f98e6aa46f20eae09580e7db73826b9 (diff) |
Merge remote-tracking branch 'remotes/upstream-stable/linux-3.4.y' into tilt-3.4
Conflicts:
arch/arm/kernel/smp.c
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/cgroup.c | 41 | ||||
-rw-r--r-- | kernel/sys.c | 12 |
2 files changed, 17 insertions, 36 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 2f0d7542c0d2..c908354cace9 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1871,9 +1871,8 @@ static void cgroup_task_migrate(struct cgroup *cgrp, struct cgroup *oldcgrp, * trading it for newcg is protected by cgroup_mutex, we're safe to drop * it here; it will be freed under RCU. */ - put_css_set(oldcg); - set_bit(CGRP_RELEASABLE, &oldcgrp->flags); + put_css_set(oldcg); } /** @@ -4516,31 +4515,20 @@ static const struct file_operations proc_cgroupstats_operations = { * * A pointer to the shared css_set was automatically copied in * fork.c by dup_task_struct(). However, we ignore that copy, since - * it was not made under the protection of RCU, cgroup_mutex or - * threadgroup_change_begin(), so it might no longer be a valid - * cgroup pointer. cgroup_attach_task() might have already changed - * current->cgroups, allowing the previously referenced cgroup - * group to be removed and freed. - * - * Outside the pointer validity we also need to process the css_set - * inheritance between threadgoup_change_begin() and - * threadgoup_change_end(), this way there is no leak in any process - * wide migration performed by cgroup_attach_proc() that could otherwise - * miss a thread because it is too early or too late in the fork stage. + * it was not made under the protection of RCU or cgroup_mutex, so + * might no longer be a valid cgroup pointer. cgroup_attach_task() might + * have already changed current->cgroups, allowing the previously + * referenced cgroup group to be removed and freed. * * At the point that cgroup_fork() is called, 'current' is the parent * task, and the passed argument 'child' points to the child task. */ void cgroup_fork(struct task_struct *child) { - /* - * We don't need to task_lock() current because current->cgroups - * can't be changed concurrently here. The parent obviously hasn't - * exited and called cgroup_exit(), and we are synchronized against - * cgroup migration through threadgroup_change_begin(). - */ + task_lock(current); child->cgroups = current->cgroups; get_css_set(child->cgroups); + task_unlock(current); INIT_LIST_HEAD(&child->cg_list); } @@ -4593,19 +4581,10 @@ void cgroup_post_fork(struct task_struct *child) */ if (use_task_css_set_links) { write_lock(&css_set_lock); - if (list_empty(&child->cg_list)) { - /* - * It's safe to use child->cgroups without task_lock() - * here because we are protected through - * threadgroup_change_begin() against concurrent - * css_set change in cgroup_task_migrate(). Also - * the task can't exit at that point until - * wake_up_new_task() is called, so we are protected - * against cgroup_exit() setting child->cgroup to - * init_css_set. - */ + task_lock(child); + if (list_empty(&child->cg_list)) list_add(&child->cg_list, &child->cgroups->tasks); - } + task_unlock(child); write_unlock(&css_set_lock); } } diff --git a/kernel/sys.c b/kernel/sys.c index 898a84c9df5b..b0003db7fea0 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1180,15 +1180,16 @@ DECLARE_RWSEM(uts_sem); * Work around broken programs that cannot handle "Linux 3.0". * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40 */ -static int override_release(char __user *release, int len) +static int override_release(char __user *release, size_t len) { int ret = 0; - char buf[65]; if (current->personality & UNAME26) { - char *rest = UTS_RELEASE; + const char *rest = UTS_RELEASE; + char buf[65] = { 0 }; int ndots = 0; unsigned v; + size_t copy; while (*rest) { if (*rest == '.' && ++ndots >= 3) @@ -1198,8 +1199,9 @@ static int override_release(char __user *release, int len) rest++; } v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40; - snprintf(buf, len, "2.6.%u%s", v, rest); - ret = copy_to_user(release, buf, len); + copy = clamp_t(size_t, len, 1, sizeof(buf)); + copy = scnprintf(buf, copy, "2.6.%u%s", v, rest); + ret = copy_to_user(release, buf, copy + 1); } return ret; } |