remarkable-linux/kernel
David Rientjes c11600e4fe mm, mempolicy: task->mempolicy must be NULL before dropping final reference
KASAN allocates memory from the page allocator as part of
kmem_cache_free(), and that can reference current->mempolicy through any
number of allocation functions.  It needs to be NULL'd out before the
final reference is dropped to prevent a use-after-free bug:

	BUG: KASAN: use-after-free in alloc_pages_current+0x363/0x370 at addr ffff88010b48102c
	CPU: 0 PID: 15425 Comm: trinity-c2 Not tainted 4.8.0-rc2+ #140
	...
	Call Trace:
		dump_stack
		kasan_object_err
		kasan_report_error
		__asan_report_load2_noabort
		alloc_pages_current	<-- use after free
		depot_save_stack
		save_stack
		kasan_slab_free
		kmem_cache_free
		__mpol_put		<-- free
		do_exit

This patch sets current->mempolicy to NULL before dropping the final
reference.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1608301442180.63329@chino.kir.corp.google.com
Fixes: cd11016e5f ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB")
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>	[4.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-01 17:52:01 -07:00
..
bpf bpf: fix bpf_skb_in_cgroup helper naming 2016-08-12 21:53:33 -07:00
configs kconfig: tinyconfig: provide whole choice blocks to avoid warnings 2016-09-01 17:52:01 -07:00
debug
events perf/core: Use this_cpu_ptr() when stopping AUX events 2016-08-24 15:03:10 +02:00
gcov gcov: add support for gcc version >= 6 2016-07-15 14:54:27 +09:00
irq genirq/affinity: Use get/put_online_cpus around cpumask operations 2016-08-22 11:22:44 +02:00
livepatch modules: add ro_after_init support 2016-08-04 10:16:55 +09:30
locking locking/pvqspinlock: Fix a bug in qstat_read() 2016-08-10 14:13:29 +02:00
power Merge branch 'pm-sleep' 2016-08-18 03:27:08 +02:00
printk printk/nmi: avoid direct printk()-s from __printk_nmi_flush() 2016-09-01 17:52:01 -07:00
rcu Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-07-29 13:55:30 -07:00
sched sched/cputime: Resync steal time when guest & host lose sync 2016-08-18 11:19:48 +02:00
time timekeeping: Cap array access in timekeeping_debug 2016-08-24 09:34:32 +02:00
trace block: Fix secure erase 2016-08-16 09:16:51 -06:00
.gitignore
acct.c
async.c
audit.c Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit 2016-07-29 17:54:17 -07:00
audit.h Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit 2016-07-29 17:54:17 -07:00
audit_fsnotify.c
audit_tree.c
audit_watch.c
auditfilter.c audit: add fields to exclude filter by reusing user filter 2016-06-27 11:01:00 -04:00
auditsc.c Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit 2016-07-29 17:54:17 -07:00
backtracetest.c
bounds.c
capability.c kernel: Add noaudit variant of ns_capable() 2016-06-06 20:16:18 +10:00
cgroup.c Merge branch 'for-4.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2016-07-29 14:29:04 -07:00
cgroup_freezer.c
cgroup_pids.c cgroup: Use lld instead of ld when printing pids controller events_limit 2016-06-21 15:03:36 -04:00
compat.c
configs.c
context_tracking.c
cpu.c timers/core: Correct callback order during CPU hot plug 2016-07-28 18:56:22 +02:00
cpu_pm.c
cpuset.c cpuset: make sure new tasks conform to the current config of the cpuset 2016-08-09 23:58:01 -04:00
crash_dump.c
cred.c cred: Reject inodes with invalid ids in set_create_file_as() 2016-06-30 18:05:09 -05:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c mm, mempolicy: task->mempolicy must be NULL before dropping final reference 2016-09-01 17:52:01 -07:00
extable.c
fork.c cgroup: reduce read locked section of cgroup_threadgroup_rwsem during fork 2016-08-17 09:54:52 -04:00
freezer.c freezer, oom: check TIF_MEMDIE on the correct task 2016-07-28 16:07:41 -07:00
futex.c futex: Assume all mappings are private on !MMU systems 2016-07-29 18:44:14 +02:00
futex_compat.c
groups.c
hung_task.c
irq_work.c
jump_label.c powerpc updates for 4.8 #2 2016-08-05 09:00:54 -04:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kernel/kcov: unproxify debugfs file's fops 2016-06-15 04:56:35 -07:00
kexec.c kexec: allow architectures to override boot mapping 2016-08-02 19:35:27 -04:00
kexec_core.c kexec: add restriction on kexec_load() segment sizes 2016-08-02 19:35:31 -04:00
kexec_file.c kexec: fix double-free when failing to relocate the purgatory 2016-09-01 17:52:01 -07:00
kexec_internal.h
kmod.c
kprobes.c
ksysfs.c kexec: add a kexec_crash_loaded() function 2016-08-02 19:35:30 -04:00
kthread.c
latencytop.c
Makefile ELF/MIPS build fix 2016-05-23 17:04:14 -07:00
membarrier.c
memremap.c libnvdimm for 4.8 2016-07-28 17:38:16 -07:00
module-internal.h
module.c Removed the MODULE_SIG_FORCE-means-no-MODULE_FORCE_LOAD patch. 2016-08-04 09:14:38 -04:00
module_signing.c
notifier.c
nsproxy.c
padata.c kernel/padata.c: hide unused functions 2016-05-19 19:12:14 -07:00
panic.c kexec: use core_param for crash_kexec_post_notifiers boot option 2016-08-02 19:35:29 -04:00
params.c
pid.c remove lots of IS_ERR_VALUE abuses 2016-05-27 15:26:11 -07:00
pid_namespace.c
profile.c profile: Convert to hotplug state machine 2016-07-15 10:41:42 +02:00
ptrace.c tree-wide: replace config_enabled() with IS_ENABLED() 2016-08-04 08:50:07 -04:00
range.c
reboot.c
relay.c relay: add global mode support for buffer-only channels 2016-08-02 19:35:41 -04:00
resource.c
seccomp.c seccomp: Fix tracer exit notifications during fatal signals 2016-08-30 16:12:46 -07:00
signal.c signals: Use hrtimer for sigtimedwait() 2016-07-07 10:35:07 +02:00
smp.c Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-07-29 13:55:30 -07:00
smpboot.c
smpboot.h
softirq.c
stacktrace.c
stop_machine.c stop_machine: Touch_nmi_watchdog() after MULTI_STOP_PREPARE 2016-07-27 11:12:11 +02:00
sys.c prctl: make PR_SET_THP_DISABLE wait for mmap_sem killable 2016-05-23 17:04:14 -07:00
sys_ni.c
sysctl.c sysctl: handle error writing UINT_MAX to u32 fields 2016-08-26 17:39:35 -07:00
sysctl_binary.c kernel/sysctl_binary.c: use generic UUID library 2016-05-20 17:58:30 -07:00
task_work.c task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works 2016-08-02 19:35:02 -04:00
taskstats.c
test_kprobes.c
torture.c torture: Stop onoff task if there is only one cpu 2016-06-14 16:03:28 -07:00
tracepoint.c
tsacct.c
uid16.c
up.c
user-return-notifier.c
user.c
user_namespace.c fs: Limit file caps to the user namespace of the super block 2016-06-24 10:40:31 -05:00
utsname.c
utsname_sysctl.c
watchdog.c Revert "perf/x86/intel, watchdog: Switch NMI watchdog to ref cycles on x86" 2016-07-10 20:58:36 +02:00
workqueue.c Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-07-29 13:55:30 -07:00
workqueue_internal.h