Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
timens: Remove dependency on the vDSO
Previously, missing time namespace support in the vDSO meant that time
namespaces needed to be disabled globally. This was expressed in a hard
dependency on the generic vDSO library. This also meant that architectures
without any vDSO or only a stub vDSO could not enable time namespaces.
Now that all architectures using a real vDSO are using the generic library,
that dependency is not necessary anymore.
Remove the dependency and let all architectures enable time namespaces.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260326-vdso-timens-decoupling-v2-2-c82693a7775f@linutronix.de
authored by
Thomas Weißschuh
and committed by
Thomas Gleixner
1b6c8928
5dc9cf83
+54
-18
+16
-12
include/linux/time_namespace.h
+16
-12
include/linux/time_namespace.h
···
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struct ucounts *ucounts;
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struct ns_common ns;
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struct timens_offsets offsets;
28
+
#ifdef CONFIG_TIME_NS_VDSO
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struct page *vvar_page;
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+
#endif
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/* If set prevents changing offsets after any task joined namespace. */
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bool frozen_offsets;
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} __randomize_layout;
···
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return container_of(ns, struct time_namespace, ns);
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}
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void __init time_ns_init(void);
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-
extern void timens_commit(struct task_struct *tsk, struct time_namespace *ns);
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static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
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{
···
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struct time_namespace *old_ns);
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void free_time_ns(struct time_namespace *ns);
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void timens_on_fork(struct nsproxy *nsproxy, struct task_struct *tsk);
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-
struct page *find_timens_vvar_page(struct vm_area_struct *vma);
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static inline void put_time_ns(struct time_namespace *ns)
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{
···
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{
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}
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-
static inline void timens_commit(struct task_struct *tsk,
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-
struct time_namespace *ns)
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{
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}
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-
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static inline struct time_namespace *get_time_ns(struct time_namespace *ns)
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{
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return NULL;
···
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return;
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}
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-
static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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-
{
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-
return NULL;
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-
}
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-
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static inline void timens_add_monotonic(struct timespec64 *ts) { }
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static inline void timens_add_boottime(struct timespec64 *ts) { }
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···
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return tim;
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}
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#endif
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+
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#ifdef CONFIG_TIME_NS_VDSO
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extern void timens_commit(struct task_struct *tsk, struct time_namespace *ns);
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struct page *find_timens_vvar_page(struct vm_area_struct *vma);
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+
#else /* !CONFIG_TIME_NS_VDSO */
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static inline void timens_commit(struct task_struct *tsk, struct time_namespace *ns)
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{
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}
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+
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static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma)
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{
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return NULL;
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}
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#endif /* CONFIG_TIME_NS_VDSO */
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#endif /* _LINUX_TIMENS_H */
+3
-1
init/Kconfig
+3
-1
init/Kconfig
···
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config TIME_NS
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bool "TIME namespace"
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-
depends on GENERIC_GETTIMEOFDAY
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default y
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help
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In this namespace boottime and monotonic clocks can be set.
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The time will keep going with the same pace.
1393
+
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config TIME_NS_VDSO
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def_bool TIME_NS && GENERIC_GETTIMEOFDAY
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config IPC_NS
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bool "IPC namespace"
+2
-1
kernel/time/Makefile
+2
-1
kernel/time/Makefile
···
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obj-$(CONFIG_GENERIC_GETTIMEOFDAY) += vsyscall.o
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obj-$(CONFIG_DEBUG_FS) += timekeeping_debug.o
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obj-$(CONFIG_TEST_UDELAY) += test_udelay.o
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-
obj-$(CONFIG_TIME_NS) += namespace.o namespace_vdso.o
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obj-$(CONFIG_TIME_NS) += namespace.o
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obj-$(CONFIG_TIME_NS_VDSO) += namespace_vdso.o
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obj-$(CONFIG_TEST_CLOCKSOURCE_WATCHDOG) += clocksource-wdtest.o
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obj-$(CONFIG_TIME_KUNIT_TEST) += time_test.o
+4
-4
kernel/time/namespace.c
+4
-4
kernel/time/namespace.c
···
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if (!ns)
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goto fail_dec;
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-
ns->vvar_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
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-
if (!ns->vvar_page)
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err = timens_vdso_alloc_vvar_page(ns);
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if (err)
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goto fail_free;
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err = ns_common_init(ns);
···
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return ns;
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fail_free_page:
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-
__free_page(ns->vvar_page);
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+
timens_vdso_free_vvar_page(ns);
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fail_free:
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kfree(ns);
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fail_dec:
···
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dec_time_namespaces(ns->ucounts);
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put_user_ns(ns->user_ns);
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ns_common_free(ns);
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-
__free_page(ns->vvar_page);
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+
timens_vdso_free_vvar_page(ns);
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/* Concurrent nstree traversal depends on a grace period. */
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kfree_rcu(ns, ns.ns_rcu);
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}
+15
kernel/time/namespace_internal.h
+15
kernel/time/namespace_internal.h
···
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#include <linux/mutex.h>
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+
struct time_namespace;
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/*
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* Protects possibly multiple offsets writers racing each other
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* and tasks entering the namespace.
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*/
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extern struct mutex timens_offset_lock;
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#ifdef CONFIG_TIME_NS_VDSO
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int timens_vdso_alloc_vvar_page(struct time_namespace *ns);
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void timens_vdso_free_vvar_page(struct time_namespace *ns);
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#else /* !CONFIG_TIME_NS_VDSO */
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static inline int timens_vdso_alloc_vvar_page(struct time_namespace *ns)
20
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{
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return 0;
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}
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static inline void timens_vdso_free_vvar_page(struct time_namespace *ns)
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{
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}
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#endif /* CONFIG_TIME_NS_VDSO */
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#endif /* _TIME_NAMESPACE_INTERNAL_H */
+14
kernel/time/namespace_vdso.c
+14
kernel/time/namespace_vdso.c
···
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timens_set_vvar_page(tsk, ns);
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vdso_join_timens(tsk, ns);
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}
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+
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+
int timens_vdso_alloc_vvar_page(struct time_namespace *ns)
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+
{
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ns->vvar_page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
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+
if (!ns->vvar_page)
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return -ENOMEM;
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+
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return 0;
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+
}
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+
157
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void timens_vdso_free_vvar_page(struct time_namespace *ns)
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+
{
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__free_page(ns->vvar_page);
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+
}