Christian Brauner 9d4e752a24 namespace: allow creating empty mount namespaces ... Add support for creating a mount namespace that contains only a copy of the root mount from the caller's mount namespace, with none of the child mounts. This is useful for containers and sandboxes that want to start with a minimal mount table and populate it from scratch rather than inheriting and then tearing down the full mount tree. Two new flags are introduced: - CLONE_EMPTY_MNTNS for clone3(), using the 64-bit flag space. - UNSHARE_EMPTY_MNTNS for unshare(), reusing the CLONE_PARENT_SETTID bit which has no meaning for unshare. Both flags imply CLONE_NEWNS. For the unshare path, UNSHARE_EMPTY_MNTNS is converted to CLONE_EMPTY_MNTNS in unshare_nsproxy_namespaces() before it reaches copy_mnt_ns(), so the mount namespace code only needs to handle a single flag. In copy_mnt_ns(), when CLONE_EMPTY_MNTNS is set, clone_mnt() is used instead of copy_tree() to clone only the root mount. The caller's root and working directory are both reset to the root dentry of the new mount. The cleanup variables are changed from vfsmount pointers with __free(mntput) to struct path with __free(path_put) because the empty mount namespace path needs to release both mount and dentry references when replacing the caller's root and pwd. In the normal (non-empty) path only the mount component is set, and dput(NULL) is a no-op so path_put remains correct there as well. Link: https://patch.msgid.link/20260306-work-empty-mntns-consolidated-v1-1-6eb30529bbb0@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>		2026-03-12 13:33:55 +01:00
..
bpf	bpf-fixes	2026-03-07 12:20:37 -08:00
cgroup	cgroup: Fixes for v7.0-rc2	2026-03-03 14:25:18 -08:00
configs	Remove WARN_ALL_UNSEEDED_RANDOM kernel config option	2026-02-23 11:18:48 -08:00
debug	treewide: Replace kmalloc with kmalloc_obj for non-scalar types	2026-02-21 01:02:28 -08:00
dma	dma-mapping: avoid random addr value print out on error path	2026-02-23 08:26:54 +01:00
entry	Merge branch 'core/entry' into sched/core	2026-01-30 15:40:05 +01:00
events	perf: Fix __perf_event_overflow() vs perf_remove_from_context() race	2026-02-25 15:02:34 +01:00
futex	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
gcov	Convert more 'alloc_obj' cases to default GFP_KERNEL arguments	2026-02-21 20:03:00 -08:00
irq	Convert 'alloc_flex' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
kcsan	kcsan: test: Adjust "expect" allocation type for kmalloc_obj	2026-02-26 09:54:08 -08:00
livepatch	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
liveupdate	liveupdate: luo_file: remember retrieve() status	2026-02-24 11:13:26 -08:00
locking	Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses	2026-02-22 08:26:33 -08:00
module	module: Fix kernel panic when a symbol st_shndx is out of bounds	2026-02-23 19:37:28 +00:00
power	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
printk	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
rcu	Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses	2026-02-22 08:26:33 -08:00
sched	Fix a DL scheduler bug that may corrupt internal metrics during	2026-03-07 17:07:13 -08:00
time	Make clock_adjtime() syscall timex validation slightly more	2026-03-07 17:09:15 -08:00
trace	bpf-fixes	2026-03-07 12:20:37 -08:00
unwind	Convert more 'alloc_obj' cases to default GFP_KERNEL arguments	2026-02-21 20:03:00 -08:00
.gitignore	…
Kconfig.freezer	…
Kconfig.hz	…
Kconfig.kexec	liveupdate: kho: move to kernel/liveupdate	2025-11-27 14:24:33 -08:00
Kconfig.locks	…
Kconfig.preempt	sched: Further restrict the preemption modes	2026-01-08 12:43:57 +01:00
Makefile	kcov: Enable context analysis	2026-01-05 16:43:34 +01:00
acct.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
async.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
audit.c	Convert 'alloc_flex' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
audit.h	audit: fix comment misindentation in audit.h	2025-10-22 19:28:06 -04:00
audit_fsnotify.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
audit_tree.c	Convert 'alloc_flex' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
audit_watch.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
auditfilter.c	Convert 'alloc_flex' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
auditsc.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
backtracetest.c	…
bounds.c	x86/asm: Remove ANNOTATE_DATA_SPECIAL usage	2025-12-03 16:53:19 +01:00
capability.c	…
cfi.c	…
compat.c	…
configs.c	…
context_tracking.c	context_tracking: Remove rcu_task_trace_heavyweight_{enter,exit}()	2026-01-01 16:39:46 +08:00
cpu.c	SPDX updates for 7.0-rc1	2026-02-17 09:46:03 -08:00
cpu_pm.c	syscore: Pass context data to callbacks	2025-11-14 10:01:52 +01:00
crash_core.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
crash_core_test.c	…
crash_dump_dm_crypt.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
crash_reserve.c	crash: let architecture decide crash memory export to iomem_resource	2025-11-12 10:00:15 -08:00
cred.c	cred: remove unused set_security_override_from_ctx()	2026-01-06 20:52:57 -05:00
delayacct.c	delayacct: fix uapi timespec64 definition	2026-02-08 00:13:32 -08:00
dma.c	…
elfcorehdr.c	…
exec_domain.c	…
exit.c	kthread: consolidate kthread exit paths to prevent use-after-free	2026-02-26 10:45:49 +01:00
exit.h	…
extable.c	…
fail_function.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
fork.c	namespace: allow creating empty mount namespaces	2026-03-12 13:33:55 +01:00
freezer.c	freezer: Clarify that only cgroup1 freezer uses PM freezer	2025-10-30 20:10:27 +01:00
gen_kheaders.sh	…
groups.c	treewide: Replace kmalloc with kmalloc_obj for non-scalar types	2026-02-21 01:02:28 -08:00
hung_task.c	hung_task: add hung_task_sys_info sysctl to dump sys info on task-hung	2025-11-20 14:03:43 -08:00
iomem.c	…
irq_work.c	…
jump_label.c	…
kallsyms.c	mm.git review status for linus..mm-nonmm-stable	2026-02-12 12:13:01 -08:00
kallsyms_internal.h	kallsyms: Get rid of kallsyms relative base	2026-01-22 15:58:22 -07:00
kallsyms_selftest.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
kallsyms_selftest.h	…
kcmp.c	…
kcov.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
kexec.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
kexec_core.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
kexec_elf.c	…
kexec_file.c	kexec: derive purgatory entry from symbol	2026-01-31 16:16:07 -08:00
kexec_internal.h	…
kheaders.c	…
kprobes.c	Convert 'alloc_flex' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
kstack_erase.c	sysctl: remove __user qualifier from stack_erasing_sysctl buffer argument	2025-11-27 15:44:53 +01:00
ksyms_common.c	…
ksysfs.c	kexec: move sysfs entries to /sys/kernel/kexec	2025-11-27 14:24:42 -08:00
kthread.c	kthread: consolidate kthread exit paths to prevent use-after-free	2026-02-26 10:45:49 +01:00
latencytop.c	…
module_signature.c	…
notifier.c	…
nscommon.c	nsfs: tighten permission checks for ns iteration ioctls	2026-02-27 22:00:08 +01:00
nsproxy.c	namespace: allow creating empty mount namespaces	2026-03-12 13:33:55 +01:00
nstree.c	nstree: tighten permission checks for listing	2026-02-27 22:00:11 +01:00
padata.c	Convert more 'alloc_obj' cases to default GFP_KERNEL arguments	2026-02-21 20:03:00 -08:00
panic.c	panic: add panic_force_cpu= parameter to redirect panic to a specific CPU	2026-02-03 08:21:26 -08:00
params.c	Convert more 'alloc_obj' cases to default GFP_KERNEL arguments	2026-02-21 20:03:00 -08:00
pid.c	Revert "pid: make __task_pid_nr_ns(ns => NULL) safe for zombie callers"	2026-02-10 11:39:30 +01:00
pid_namespace.c	pid: rely on common reference count behavior	2025-11-11 10:01:32 +01:00
pid_sysctl.h	…
profile.c	…
ptrace.c	rseq: Introduce struct rseq_data	2025-11-04 08:30:50 +01:00
range.c	…
reboot.c	treewide: Replace kmalloc with kmalloc_obj for non-scalar types	2026-02-21 01:02:28 -08:00
regset.c	…
relay.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
resource.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
resource_kunit.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
rseq.c	rseq: slice ext: Ensure rseq feature size differs from original rseq size	2026-02-23 11:19:19 +01:00
scftorture.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
scs.c	scs: fix a wrong parameter in __scs_magic	2025-11-12 10:00:13 -08:00
seccomp.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
signal.c	compiler-context-analysis: Remove __cond_lock() function-like helper	2026-01-05 16:43:33 +01:00
smp.c	smp: Introduce a helper function to check for pending IPIs	2025-11-19 18:06:50 +01:00
smpboot.c	…
smpboot.h	…
softirq.c	…
stacktrace.c	…
static_call.c	…
static_call_inline.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
stop_machine.c	…
sys.c	RISC-V updates for v7.0	2026-02-12 19:17:44 -08:00
sys_ni.c	rseq: Implement sys_rseq_slice_yield()	2026-01-22 11:11:17 +01:00
sysctl-test.c	…
sysctl.c	sysctl: replace SYSCTL_INT_CONV_CUSTOM macro with functions	2026-01-06 11:27:10 +01:00
task_work.c	task_work: Fix NMI race condition	2025-10-29 10:29:54 +01:00
taskstats.c	…
torture.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
tracepoint.c	Convert 'alloc_flex' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
tsacct.c	tsacct: skip all kernel threads	2026-01-26 19:07:13 -08:00
ucount.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
uid16.c	…
uid16.h	…
umh.c	treewide: Replace kmalloc with kmalloc_obj for non-scalar types	2026-02-21 01:02:28 -08:00
up.c	…
user-return-notifier.c	…
user.c	ns: drop custom reference count initialization for initial namespaces	2025-11-11 10:01:32 +01:00
user_namespace.c	Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses	2026-02-22 08:26:33 -08:00
utsname.c	namespace-6.18-rc1	2025-09-29 11:20:29 -07:00
utsname_sysctl.c	…
vhost_task.c	Convert 'alloc_obj' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
vmcore_info.c	mm.git review status for linus..mm-nonmm-stable	2026-02-12 12:13:01 -08:00
watch_queue.c	Convert 'alloc_flex' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
watchdog.c	watchdog/softlockup: fix sample ring index wrap in need_counting_irqs()	2026-02-08 00:13:34 -08:00
watchdog_buddy.c	…
watchdog_perf.c	watchdog/hardlockup: simplify perf event probe and remove per-cpu dependency	2026-02-08 00:13:35 -08:00
workqueue.c	Convert 'alloc_flex' family to use the new default GFP_KERNEL argument	2026-02-21 17:09:51 -08:00
workqueue_internal.h	…