From: "tip-bot2 for Dmitry Safonov" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Andrei Vagin <avagin@gmail.com>, Dmitry Safonov <dima@arista.com>,
Thomas Gleixner <tglx@linutronix.de>, x86 <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: [tip: timers/core] x86/vdso: Zap vvar pages when switching to a time namespace
Date: Mon, 13 Jan 2020 19:09:25 -0000 [thread overview]
Message-ID: <157894256597.19145.2579311477753145409.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20191112012724.250792-27-dima@arista.com>
The following commit has been merged into the timers/core branch of tip:
Commit-ID: fa8acdc8f8f58be60e43bae6ead83c7dd332337a
Gitweb: https://git.kernel.org/tip/fa8acdc8f8f58be60e43bae6ead83c7dd332337a
Author: Dmitry Safonov <dima@arista.com>
AuthorDate: Tue, 12 Nov 2019 01:27:15
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Mon, 13 Jan 2020 08:10:57 +01:00
x86/vdso: Zap vvar pages when switching to a time namespace
The VVAR page layout depends on whether a task belongs to the root or
non-root time namespace. Whenever a task changes its namespace, the VVAR
page tables are cleared and then they will be re-faulted with a
corresponding layout.
Co-developed-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20191112012724.250792-27-dima@arista.com
---
arch/x86/entry/vdso/vma.c | 27 +++++++++++++++++++++++++++
include/linux/time_namespace.h | 9 +++++++++
kernel/time/namespace.c | 10 ++++++++++
3 files changed, 46 insertions(+)
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index d2fd8a5..c1b8496 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -51,6 +51,7 @@ void __init init_vdso_image(const struct vdso_image *image)
image->alt_len));
}
+static const struct vm_special_mapping vvar_mapping;
struct linux_binprm;
static vm_fault_t vdso_fault(const struct vm_special_mapping *sm,
@@ -128,6 +129,32 @@ static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
return NULL;
}
+
+/*
+ * The vvar page layout depends on whether a task belongs to the root or
+ * non-root time namespace. Whenever a task changes its namespace, the VVAR
+ * page tables are cleared and then they will re-faulted with a
+ * corresponding layout.
+ * See also the comment near timens_setup_vdso_data() for details.
+ */
+int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
+{
+ struct mm_struct *mm = task->mm;
+ struct vm_area_struct *vma;
+
+ if (down_write_killable(&mm->mmap_sem))
+ return -EINTR;
+
+ for (vma = mm->mmap; vma; vma = vma->vm_next) {
+ unsigned long size = vma->vm_end - vma->vm_start;
+
+ if (vma_is_special_mapping(vma, &vvar_mapping))
+ zap_page_range(vma, vma->vm_start, size);
+ }
+
+ up_write(&mm->mmap_sem);
+ return 0;
+}
#else
static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma)
{
diff --git a/include/linux/time_namespace.h b/include/linux/time_namespace.h
index 6b7767f..04a2ba8 100644
--- a/include/linux/time_namespace.h
+++ b/include/linux/time_namespace.h
@@ -31,6 +31,9 @@ struct time_namespace {
extern struct time_namespace init_time_ns;
#ifdef CONFIG_TIME_NS
+extern int vdso_join_timens(struct task_struct *task,
+ struct time_namespace *ns);
+
static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
{
kref_get(&ns->kref);
@@ -77,6 +80,12 @@ static inline ktime_t timens_ktime_to_host(clockid_t clockid, ktime_t tim)
}
#else
+static inline int vdso_join_timens(struct task_struct *task,
+ struct time_namespace *ns)
+{
+ return 0;
+}
+
static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
{
return NULL;
diff --git a/kernel/time/namespace.c b/kernel/time/namespace.c
index d705c15..0732964 100644
--- a/kernel/time/namespace.c
+++ b/kernel/time/namespace.c
@@ -281,6 +281,7 @@ static void timens_put(struct ns_common *ns)
static int timens_install(struct nsproxy *nsproxy, struct ns_common *new)
{
struct time_namespace *ns = to_time_ns(new);
+ int err;
if (!current_is_single_threaded())
return -EUSERS;
@@ -291,6 +292,10 @@ static int timens_install(struct nsproxy *nsproxy, struct ns_common *new)
timens_set_vvar_page(current, ns);
+ err = vdso_join_timens(current, ns);
+ if (err)
+ return err;
+
get_time_ns(ns);
put_time_ns(nsproxy->time_ns);
nsproxy->time_ns = ns;
@@ -305,6 +310,7 @@ int timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk)
{
struct ns_common *nsc = &nsproxy->time_ns_for_children->ns;
struct time_namespace *ns = to_time_ns(nsc);
+ int err;
/* create_new_namespaces() already incremented the ref counter */
if (nsproxy->time_ns == nsproxy->time_ns_for_children)
@@ -312,6 +318,10 @@ int timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk)
timens_set_vvar_page(tsk, ns);
+ err = vdso_join_timens(tsk, ns);
+ if (err)
+ return err;
+
get_time_ns(ns);
put_time_ns(nsproxy->time_ns);
nsproxy->time_ns = ns;
next prev parent reply other threads:[~2020-01-13 19:12 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-12 1:26 [PATCHv8 00/34] kernel: Introduce Time Namespace Dmitry Safonov
2019-11-12 1:26 ` [PATCHv8 01/34] lib/vdso: Add unlikely() hint into vdso_read_begin() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 02/34] lib/vdso: make do_hres and do_coarse as __always_inline Dmitry Safonov
2020-01-10 9:45 ` Vincenzo Frascino
2020-01-10 11:42 ` Thomas Gleixner
2020-01-10 11:47 ` Vincenzo Frascino
2020-01-10 12:02 ` Thomas Gleixner
2020-01-10 12:18 ` Vincenzo Frascino
2020-01-13 5:27 ` Andrei Vagin
2020-01-13 19:09 ` [tip: timers/core] lib/vdso: Mark do_hres() and do_coarse() " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 03/34] ns: Introduce Time Namespace Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2020-01-27 14:12 ` [PATCHv8 03/34] " Dmitry Vyukov
2020-01-27 14:19 ` Dmitry Safonov
2020-02-17 14:20 ` Time Namespaces: CLONE_NEWTIME and clone3()? Michael Kerrisk
2020-02-17 14:59 ` Christian Brauner
2020-02-17 21:47 ` Michael Kerrisk (man-pages)
2020-02-17 23:03 ` Christian Brauner
2020-02-17 23:29 ` Thomas Gleixner
2020-02-18 2:37 ` Eric W. Biederman
2020-02-18 17:11 ` Adrian Reber
2020-02-18 17:26 ` Christian Brauner
2019-11-12 1:26 ` [PATCHv8 04/34] time: Add timens_offsets to be used for tasks in timens Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] time: Add timens_offsets to be used for tasks in time namespace tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 05/34] posix-clocks: Rename the clock_get() callback to clock_get_timespec() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 06/34] posix-clocks: Rename .clock_get_timespec() callbacks accordingly Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 07/34] alarmtimer: Rename gettime() callback to get_ktime() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 08/34] alarmtimer: Provide get_timespec() callback Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 09/34] posix-clocks: Introduce clock_get_ktime() callback Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 10/34] posix-timers: Use clock_get_ktime() in common_timer_get() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 11/34] posix-clocks: Wire up clock_gettime() with timens offsets Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 12/34] kernel: Add do_timens_ktime_to_host() helper Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] time: " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 13/34] timerfd: Make timerfd_settime() time namespace aware Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 14/34] posix-timers: Make timer_settime() " Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 15/34] alarmtimer: Make nanosleep " Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] alarmtimer: Make nanosleep() " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 16/34] hrtimers: Prepare hrtimer_nanosleep() for time namespaces Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 17/34] posix-timers: Make clock_nanosleep() time namespace aware Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 18/34] fs/proc: Respect boottime inside time namespace for /proc/uptime Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 19/34] x86/vdso: Restrict splitting VVAR VMA Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 20/34] lib/vdso: Prepare for time namespace support Dmitry Safonov
2020-01-12 10:32 ` Thomas Gleixner
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-01-14 13:02 ` tip-bot2 for Thomas Gleixner
2019-11-12 1:27 ` [PATCHv8 21/34] x86/vdso: Provide vdso_data offset on vvar_page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 22/34] x86/vdso: Add timens page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] x86/vdso: Add time napespace page tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 23/34] time: Allocate per-timens vvar page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 24/34] x86/vdso: Handle faults on timens page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 25/34] x86/vdso: On timens page fault prefault also VVAR page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 26/34] x86/vdso: Zap vvar pages on switch a time namspace Dmitry Safonov
2020-01-13 19:09 ` tip-bot2 for Dmitry Safonov [this message]
2020-01-14 13:02 ` [tip: timers/core] x86/vdso: Zap vvar pages when switching to a time namespace tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 27/34] fs/proc: Introduce /proc/pid/timens_offsets Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 28/34] selftests/timens: Add Time Namespace test for supported clocks Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 29/34] selftests/timens: Add a test for timerfd Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 30/34] selftests/timens: Add a test for clock_nanosleep() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 31/34] selftests/timens: Add procfs selftest Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 32/34] selftests/timens: Add timer offsets test Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 33/34] selftests/timens: Add a simple perf test for clock_gettime() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 34/34] selftests/timens: Check for right timens offsets after fork and exec Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-21 18:05 ` [PATCHv8 00/34] kernel: Introduce Time Namespace Andrei Vagin
2019-12-11 20:38 ` Dmitry Safonov
2020-01-09 21:09 ` Thomas Gleixner
2020-01-10 9:52 ` Vincenzo Frascino
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