WSL2-Linux-Kernel/kernel
Pavel Emelyanov 28f300d236 Fix user namespace exiting OOPs
It turned out, that the user namespace is released during the do_exit() in
exit_task_namespaces(), but the struct user_struct is released only during the
put_task_struct(), i.e.  MUCH later.

On debug kernels with poisoned slabs this will cause the oops in
uid_hash_remove() because the head of the chain, which resides inside the
struct user_namespace, will be already freed and poisoned.

Since the uid hash itself is required only when someone can search it, i.e.
when the namespace is alive, we can safely unhash all the user_struct-s from
it during the namespace exiting.  The subsequent free_uid() will complete the
user_struct destruction.

For example simple program

   #include <sched.h>

   char stack[2 * 1024 * 1024];

   int f(void *foo)
   {
   	return 0;
   }

   int main(void)
   {
   	clone(f, stack + 1 * 1024 * 1024, 0x10000000, 0);
   	return 0;
   }

run on kernel with CONFIG_USER_NS turned on will oops the
kernel immediately.

This was spotted during OpenVZ kernel testing.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
Acked-by: "Serge E. Hallyn" <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-19 11:24:18 -07:00
..
irq request_irq: fix DEBUG_SHIRQ handling 2007-08-31 01:42:23 -07:00
power PM: Fix dependencies of CONFIG_SUSPEND and CONFIG_HIBERNATION 2007-08-31 01:42:22 -07:00
time clockevents: prevent stale tick update on offline cpu 2007-09-16 15:36:43 +02:00
.gitignore
Kconfig.hz
Kconfig.preempt [PATCH] sched: arch preempt notifier mechanism 2007-07-26 13:40:43 +02:00
Makefile user namespace: add the framework 2007-07-16 09:05:47 -07:00
acct.c Cleanup non-arch xtime uses, use get_seconds() or current_kernel_time(). 2007-07-25 10:09:20 -07:00
audit.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
audit.h Audit: add TTY input auditing 2007-07-16 09:05:47 -07:00
auditfilter.c [PATCH] allow audit filtering on bit & operations 2007-07-22 09:57:02 -04:00
auditsc.c kernel/auditsc.c: fix an off-by-one 2007-08-22 19:52:44 -07:00
capability.c
compat.c signal/timer/event: timerfd compat code 2007-05-11 08:29:36 -07:00
configs.c use simple_read_from_buffer in kernel/ 2007-05-09 12:30:49 -07:00
cpu.c PM: Fix dependencies of CONFIG_SUSPEND and CONFIG_HIBERNATION 2007-08-31 01:42:22 -07:00
cpuset.c usermodehelper: Tidy up waiting 2007-07-18 08:47:40 -07:00
delayacct.c sched: update delay-accounting to use CFS's precise stats 2007-07-09 18:52:00 +02:00
die_notifier.c
dma.c
exec_domain.c
exit.c Assign task_struct.exit_code before taskstats_exit() 2007-08-31 01:42:22 -07:00
extable.c
fork.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
futex.c futex_unlock_pi() hurts my brain and may cause application deadlock 2007-08-22 19:52:44 -07:00
futex_compat.c futex_compat: fix list traversal bugs 2007-09-11 17:21:20 -07:00
hrtimer.c Cache xtime every call to update_wall_time 2007-07-25 10:17:44 -07:00
itimer.c
kallsyms.c kallsyms: make KSYM_NAME_LEN include space for trailing '\0' 2007-07-17 10:23:03 -07:00
kexec.c
kfifo.c is_power_of_2: kernel/kfifo.c 2007-07-16 09:05:50 -07:00
kmod.c Restore call_usermodehelper_pipe() behaviour 2007-09-11 17:21:20 -07:00
kprobes.c fix compilation with gcc 4.2 2007-08-11 15:47:42 -07:00
ksysfs.c FRV: Fix linkage problems 2007-07-20 12:01:34 -07:00
kthread.c kthread: silence bogus section mismatch warning 2007-07-31 15:39:42 -07:00
latency.c
lockdep.c lockdep debugging: give stacktrace for init_error 2007-07-19 10:04:49 -07:00
lockdep_internals.h
lockdep_proc.c Fix leak on /proc/lockdep_stats 2007-07-31 15:39:40 -07:00
module.c Fix Off-by-one in /sys/module/*/refcnt 2007-08-22 14:35:35 -07:00
mutex-debug.c
mutex-debug.h
mutex.c lockstat: measure lock bouncing 2007-07-19 10:04:49 -07:00
mutex.h
nsproxy.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
panic.c Report that kernel is tainted if there was an OOPS 2007-07-17 10:23:02 -07:00
params.c modules: better error messages when modules fail to load due to a sysfs problem. 2007-07-30 14:25:23 -07:00
pid.c namespace: ensure clone_flags are always stored in an unsigned long 2007-07-16 09:05:48 -07:00
posix-cpu-timers.c sched: make posix-cpu-timers use CFS's accounting information 2007-07-09 18:51:58 +02:00
posix-timers.c posix-timers: fix creation race 2007-08-22 19:52:46 -07:00
printk.c fix - ensure we don't use bootconsoles after init has been released 2007-08-21 20:23:53 -07:00
profile.c fix compilation with gcc 4.2 2007-08-11 15:47:42 -07:00
ptrace.c Fix spurious syscall tracing after PTRACE_DETACH + PTRACE_ATTACH 2007-09-10 18:57:47 -07:00
rcupdate.c Add suspend-related notifications for CPU hotplug 2007-05-09 12:30:56 -07:00
rcutorture.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
relay.c Fix a use after free bug in kernel->userspace relay file support 2007-07-31 15:39:42 -07:00
resource.c
rtmutex-debug.c FUTEX: Tidy up the code 2007-07-16 09:05:49 -07:00
rtmutex-debug.h
rtmutex-tester.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
rtmutex.c FUTEX: Tidy up the code 2007-07-16 09:05:49 -07:00
rtmutex.h
rtmutex_common.h FUTEX: Tidy up the code 2007-07-16 09:05:49 -07:00
rwsem.c lockstat: hook into spinlock_t, rwlock_t, rwsem and mutex 2007-07-19 10:04:49 -07:00
sched.c sched: fix xtensa build warning 2007-09-05 14:32:49 +02:00
sched_debug.c sched: debug: fix sum_exec_runtime clearing 2007-09-05 14:32:49 +02:00
sched_fair.c sched: fix ideal_runtime calculations for reniced tasks 2007-09-05 14:32:49 +02:00
sched_idletask.c sched: remove the 'u64 now' parameter from ->put_prev_task() 2007-08-09 11:16:49 +02:00
sched_rt.c sched: optimize task_tick_rt() a bit 2007-08-24 20:39:10 +02:00
sched_stats.h [PATCH] sched: add schedstat_set() API 2007-08-02 17:41:40 +02:00
seccomp.c make seccomp zerocost in schedule 2007-07-16 09:05:50 -07:00
signal.c sigqueue_free: fix the race with collect_signal() 2007-08-31 01:42:23 -07:00
softirq.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
softlockup.c Freezer: make kernel threads nonfreezable by default 2007-07-17 10:23:02 -07:00
spinlock.c lockstat: hook into spinlock_t, rwlock_t, rwsem and mutex 2007-07-19 10:04:49 -07:00
srcu.c
stacktrace.c
stop_machine.c Fix stop_machine_run problem with naughty real time process 2007-07-16 09:05:41 -07:00
sys.c setpgid(child) fails if the child was forked by sub-thread 2007-08-31 01:42:22 -07:00
sys_ni.c diskquota: 32bit quota tools on 64bit architectures 2007-07-16 09:05:48 -07:00
sysctl.c sched: cleanup, sched_granularity -> sched_min_granularity 2007-08-25 18:41:53 +02:00
taskstats.c taskstats: add context-switch counters 2007-07-16 09:05:46 -07:00
time.c Cleanup non-arch xtime uses, use get_seconds() or current_kernel_time(). 2007-07-25 10:09:20 -07:00
timer.c Pull ia64-clocksource into release branch 2007-07-20 11:26:47 -07:00
tsacct.c Cleanup non-arch xtime uses, use get_seconds() or current_kernel_time(). 2007-07-25 10:09:20 -07:00
uid16.c
user.c Fix user namespace exiting OOPs 2007-09-19 11:24:18 -07:00
user_namespace.c Fix user namespace exiting OOPs 2007-09-19 11:24:18 -07:00
utsname.c Fix UTS corruption during clone(CLONE_NEWUTS) 2007-09-19 11:24:17 -07:00
utsname_sysctl.c remove CONFIG_UTS_NS and CONFIG_IPC_NS 2007-07-16 09:05:47 -07:00
wait.c Fix occurrences of "the the " 2007-05-09 08:57:56 +02:00
workqueue.c fix bogus hotplug cpu warning 2007-08-27 10:27:48 -07:00