[Devel] [PATCH RHEL COMMIT] ve, x86_64: add per-ve vdso mapping.
Konstantin Khorenko
khorenko at virtuozzo.com
Fri Oct 1 19:38:46 MSK 2021
The commit is pushed to "branch-rh9-5.14.vz9.1.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after ark-5.14
------>
commit ab6639e4ab3a269601c3abb6061313c6f0bb8f9f
Author: Andrey Ryabinin <ryabinin.a.a at gmail.com>
Date: Fri Oct 1 19:38:46 2021 +0300
ve, x86_64: add per-ve vdso mapping.
Make vdso mapping per-ve. This will allow per container modification
of the linux version in .note section of vdso and monotonic time.
https://jira.sw.ru/browse/PSBM-121668
Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
+++
ve: fix copy_vdso error handling
Else we would return null pointer (e.g. to cgroup_init_subsys) and
IS_ERR would say that it's not an error and the caller code
would badly consider ve_start being successful while it's not.
https://jira.sw.ru/browse/PSBM-131158
Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
+++
vdso: fix VM_BUG_ON_PAGE(PageSlab(page)) on unmap
vdso_data is mapped to userspace which means that we can't
use kmalloc() to allocate it. Kmalloc() doesn't even guarantee
that we will get page aligned memory.
kernel BUG at include/linux/mm.h:693!
RIP: 0010:unmap_page_range+0x15f2/0x2630
Call Trace:
unmap_vmas+0x11e/0x1d0
exit_mmap+0x215/0x420
mmput+0x10a/0x400
do_exit+0x98f/0x2d00
do_group_exit+0xec/0x2b0
__x64_sys_exit_group+0x3a/0x50
do_syscall_64+0xa5/0x4d0
entry_SYSCALL_64_after_hwframe+0x6a/0xdf
Use alloc_pages_exact() to allocate it. We can't use
alloc_pages(), or __get_free_pages() here since vdso_fault()
need to perform get_page() on individual sub-pages and alloc_pages()
doesn't initalize sub-pages.
https://jira.sw.ru/browse/PSBM-123551
Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
(cherry-picked from vz8 commit 12c3967a0009 ("ve, x86_64: add per-ve vdso
mapping."))
Signed-off-by: Nikita Yushchenko <nikita.yushchenko at virtuozzo.com>
---
arch/x86/entry/vdso/vma.c | 4 +++-
arch/x86/kernel/process_64.c | 2 +-
include/linux/ve.h | 3 +++
kernel/ve/ve.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 51 insertions(+), 2 deletions(-)
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 235a5794296a..e58417321af2 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -15,6 +15,7 @@
#include <linux/cpu.h>
#include <linux/ptrace.h>
#include <linux/time_namespace.h>
+#include <linux/ve.h>
#include <asm/pvclock.h>
#include <asm/vgtod.h>
@@ -391,7 +392,8 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
if (!vdso64_enabled)
return 0;
- return map_vdso_randomized(&vdso_image_64);
+
+ return map_vdso_randomized(get_exec_env()->vdso_64);
}
#ifdef CONFIG_COMPAT
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 4811c8669f92..206cdb4793f5 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -829,7 +829,7 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
return prctl_map_vdso(&vdso_image_32, arg2);
# endif
case ARCH_MAP_VDSO_64:
- return prctl_map_vdso(&vdso_image_64, arg2);
+ return prctl_map_vdso(get_exec_env()->vdso_64, arg2);
#endif
default:
diff --git a/include/linux/ve.h b/include/linux/ve.h
index 95dcd99267df..741867427f57 100644
--- a/include/linux/ve.h
+++ b/include/linux/ve.h
@@ -16,6 +16,7 @@
#include <linux/kmapset.h>
#include <linux/kthread.h>
#include <linux/vzstat.h>
+#include <asm/vdso.h>
struct nsproxy;
struct veip_struct;
@@ -71,6 +72,8 @@ struct ve_struct {
struct kthread_worker umh_worker;
struct task_struct *umh_task;
+
+ struct vdso_image *vdso_64;
};
#define VE_MEMINFO_DEFAULT 1 /* default behaviour */
diff --git a/kernel/ve/ve.c b/kernel/ve/ve.c
index 178aa658b50b..6a3248efaf07 100644
--- a/kernel/ve/ve.c
+++ b/kernel/ve/ve.c
@@ -55,6 +55,7 @@ struct ve_struct ve0 = {
2,
#endif
.meminfo_val = VE_MEMINFO_SYSTEM,
+ .vdso_64 = (struct vdso_image*)&vdso_image_64,
};
EXPORT_SYMBOL(ve0);
@@ -562,6 +563,33 @@ void ve_exit_ns(struct pid_namespace *pid_ns)
up_write(&ve->op_sem);
}
+static int copy_vdso(struct ve_struct *ve)
+{
+ const struct vdso_image *vdso_src = &vdso_image_64;
+ struct vdso_image *vdso;
+ void *vdso_data;
+
+ if (ve->vdso_64)
+ return 0;
+
+ vdso = kmemdup(vdso_src, sizeof(*vdso), GFP_KERNEL);
+ if (!vdso)
+ return -ENOMEM;
+
+ vdso_data = alloc_pages_exact(vdso_src->size, GFP_KERNEL);
+ if (!vdso_data) {
+ kfree(vdso);
+ return -ENOMEM;
+ }
+
+ memcpy(vdso_data, vdso_src->data, vdso_src->size);
+
+ vdso->data = vdso_data;
+
+ ve->vdso_64 = vdso;
+ return 0;
+}
+
static struct cgroup_subsys_state *ve_create(struct cgroup_subsys_state *parent_css)
{
struct ve_struct *ve = &ve0;
@@ -595,12 +623,18 @@ static struct cgroup_subsys_state *ve_create(struct cgroup_subsys_state *parent_
if (err)
goto err_log;
+ err = copy_vdso(ve);
+ if (err)
+ goto err_vdso;
+
do_init:
init_rwsem(&ve->op_sem);
INIT_LIST_HEAD(&ve->ve_list);
kmapset_init_key(&ve->sysfs_perms_key);
return &ve->css;
+err_vdso:
+ ve_log_destroy(ve);
err_log:
free_percpu(ve->sched_lat_ve.cur);
err_lat:
@@ -639,12 +673,22 @@ static void ve_offline(struct cgroup_subsys_state *css)
ve->ve_name = NULL;
}
+static void ve_free_vdso(struct ve_struct *ve)
+{
+ if (ve->vdso_64 == &vdso_image_64)
+ return;
+
+ free_pages_exact(ve->vdso_64->data, ve->vdso_64->size);
+ kfree(ve->vdso_64);
+}
+
static void ve_destroy(struct cgroup_subsys_state *css)
{
struct ve_struct *ve = css_to_ve(css);
kmapset_unlink(&ve->sysfs_perms_key, &sysfs_ve_perms_set);
ve_log_destroy(ve);
+ ve_free_vdso(ve);
free_percpu(ve->sched_lat_ve.cur);
kmem_cache_free(ve_cachep, ve);
}
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