linux/kernel
Andy Lutomirski 758c9373d8 membarrier: Explicitly sync remote cores when SYNC_CORE is requested
membarrier() does not explicitly sync_core() remote CPUs; instead, it
relies on the assumption that an IPI will result in a core sync.  On x86,
this may be true in practice, but it's not architecturally reliable.  In
particular, the SDM and APM do not appear to guarantee that interrupt
delivery is serializing.  While IRET does serialize, IPI return can
schedule, thereby switching to another task in the same mm that was
sleeping in a syscall.  The new task could then SYSRET back to usermode
without ever executing IRET.

Make this more robust by explicitly calling sync_core_before_usermode()
on remote cores.  (This also helps people who search the kernel tree for
instances of sync_core() and sync_core_before_usermode() -- one might be
surprised that the core membarrier code doesn't currently show up in a
such a search.)

Fixes: 70216e18e5 ("membarrier: Provide core serializing command, *_SYNC_CORE")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/776b448d5f7bd6b12690707f5ed67bcda7f1d427.1607058304.git.luto@kernel.org
2020-12-09 09:37:43 +01:00
..
bpf bpf: Relax return code check for subprograms 2020-11-14 08:17:27 -08:00
cgroup kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
configs
debug kdb: Fix pager search for multi-line strings 2020-10-01 14:44:08 +01:00
dma swiotlb: remove the tbl_dma_addr argument to swiotlb_tbl_map_single 2020-11-02 10:10:39 -05:00
entry entry: Fix the incorrect ordering of lockdep and RCU check 2020-11-04 18:06:14 +01:00
events perf: Tweak perf_event_attr::exclusive semantics 2020-11-09 18:12:36 +01:00
gcov gcov: add support for GCC 10.1 2020-09-11 09:33:54 -07:00
irq genirq/irqdomain: Add an irq_create_mapping_affinity() function 2020-11-30 12:21:31 +01:00
kcsan kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
livepatch kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
locking lockdep: Put graph lock/unlock under lock_recursion protection 2020-11-17 13:15:35 +01:00
power PM: sleep: fix typo in kernel/power/process.c 2020-10-27 19:11:44 +01:00
printk Urgent printk fix for 5.10 2020-11-27 10:38:36 -08:00
rcu Merge branch 'urgent-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu 2020-11-17 10:31:56 -08:00
sched membarrier: Explicitly sync remote cores when SYNC_CORE is requested 2020-12-09 09:37:43 +01:00
time time: Prevent undefined behaviour in timespec64_to_ns() 2020-10-26 11:48:11 +01:00
trace Tracing fixes for 5.10-rc6 2020-12-01 15:30:18 -08:00
.gitignore
acct.c kernel: acct.c: fix some kernel-doc nits 2020-10-16 11:11:19 -07:00
async.c treewide: Remove uninitialized_var() usage 2020-07-16 12:35:15 -07:00
audit.c audit: Remove redundant null check 2020-08-26 09:10:39 -04:00
audit.h audit: change unnecessary globals into statics 2020-08-17 20:26:58 -04:00
audit_fsnotify.c fsnotify: create method handle_inode_event() in fsnotify_operations 2020-07-27 23:25:50 +02:00
audit_tree.c \n 2020-08-06 19:29:51 -07:00
audit_watch.c fsnotify: create method handle_inode_event() in fsnotify_operations 2020-07-27 23:25:50 +02:00
auditfilter.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
auditsc.c audit/stable-5.9 PR 20200803 2020-08-04 14:20:26 -07:00
backtracetest.c treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD() 2020-07-30 11:15:58 -07:00
bounds.c
capability.c LSM: Signal to SafeSetID when setting group IDs 2020-10-13 09:17:34 -07:00
compat.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
configs.c
context_tracking.c context_tracking: Ensure that the critical path cannot be instrumented 2020-06-11 15:14:36 +02:00
cpu.c kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handling 2020-11-27 00:10:39 +11:00
cpu_pm.c notifier: Fix broken error handling pattern 2020-09-01 09:58:03 +02:00
crash_core.c kdump: append kernel build-id string to VMCOREINFO 2020-08-12 10:58:01 -07:00
crash_dump.c
cred.c exec: Teach prepare_exec_creds how exec treats uids & gids 2020-05-20 14:44:21 -05:00
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c don't dump the threads that had been already exiting when zapped. 2020-10-28 16:39:49 -04:00
extable.c
fail_function.c fail_function: Remove a redundant mutex unlock 2020-11-19 11:58:16 -08:00
fork.c fork: fix copy_process(CLONE_PARENT) race with the exiting ->real_parent 2020-11-08 11:18:39 -08:00
freezer.c
futex.c futex: Don't enable IRQs unconditionally in put_pi_state() 2020-11-09 14:30:30 +01:00
gen_kheaders.sh kbuild: add variables for compression tools 2020-06-06 23:42:01 +09:00
groups.c LSM: Signal to SafeSetID when setting group IDs 2020-10-13 09:17:34 -07:00
hung_task.c kernel/hung_task.c: make type annotations consistent 2020-11-02 12:14:19 -08:00
iomem.c
irq_work.c irq_work, smp: Allow irq_work on call_single_queue 2020-05-28 10:54:15 +02:00
jump_label.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
kallsyms.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kcov: make some symbols static 2020-08-12 10:58:02 -07:00
kexec.c LSM: Introduce kernel_post_load_data() hook 2020-10-05 13:37:03 +02:00
kexec_core.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
kexec_elf.c
kexec_file.c kernel/resource: move and rename IORESOURCE_MEM_DRIVER_MANAGED 2020-10-16 11:11:18 -07:00
kexec_internal.h
kheaders.c
kmod.c kmod: remove redundant "be an" in the comment 2020-08-12 10:58:01 -07:00
kprobes.c kprobes: Tell lockdep about kprobe nesting 2020-11-04 09:46:06 -05:00
ksysfs.c
kthread.c kthread_worker: prevent queuing delayed work from timer_fn when it is being canceled 2020-11-02 12:14:19 -08:00
latencytop.c
Makefile Kbuild updates for v5.10 2020-10-22 13:13:57 -07:00
module-internal.h
module.c Modules updates for v5.10 2020-10-22 13:08:57 -07:00
module_signature.c
module_signing.c
notifier.c notifier: Fix broken error handling pattern 2020-09-01 09:58:03 +02:00
nsproxy.c nsproxy: support CLONE_NEWTIME with setns() 2020-07-08 11:14:22 +02:00
padata.c padata: fix possible padata_works_lock deadlock 2020-09-04 17:51:55 +10:00
panic.c panic: don't dump stack twice on warn 2020-11-14 11:26:04 -08:00
params.c params: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
pid.c pid: move pidfd_get_pid() to pid.c 2020-10-18 09:27:10 -07:00
pid_namespace.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
profile.c
ptrace.c ptrace: Set PF_SUPERPRIV when checking capability 2020-11-17 12:53:22 -08:00
range.c kernel.h: split out min()/max() et al. helpers 2020-10-16 11:11:19 -07:00
reboot.c reboot: fix overflow parsing reboot cpu number 2020-11-14 11:26:03 -08:00
regset.c regset: kill ->get() 2020-07-27 14:31:12 -04:00
relay.c kernel/relay.c: drop unneeded initialization 2020-10-16 11:11:22 -07:00
resource.c kernel/resource: make iomem_resource implicit in release_mem_region_adjustable() 2020-10-16 11:11:18 -07:00
rseq.c
scftorture.c scftorture: Add cond_resched() to test loop 2020-08-24 18:38:38 -07:00
scs.c mm: memcontrol: account kernel stack per node 2020-08-07 11:33:25 -07:00
seccomp.c seccomp: Set PF_SUPERPRIV when checking capability 2020-11-17 12:53:22 -08:00
signal.c ptrace: fix task_join_group_stop() for the case when current is traced 2020-11-02 12:14:19 -08:00
smp.c Merge tag 'core-rcu-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-10-18 14:34:50 -07:00
smpboot.c
smpboot.h
softirq.c softirq: Add debug check to __raise_softirq_irqoff() 2020-09-16 15:18:56 +02:00
stackleak.c stackleak: let stack_erasing_sysctl take a kernel pointer buffer 2020-09-19 13:13:39 -07:00
stacktrace.c stacktrace: Remove reliable argument from arch_stack_walk() callback 2020-09-18 14:24:16 +01:00
static_call.c static_call: Fix return type of static_call_init 2020-10-02 21:18:25 +02:00
stop_machine.c stop_machine, rcu: Mark functions as notrace 2020-10-26 12:12:27 +01:00
sys.c kernel/sys.c: fix prototype of prctl_get_tid_address() 2020-10-25 11:44:16 -07:00
sys_ni.c mm/madvise: introduce process_madvise() syscall: an external memory hinting API 2020-10-18 09:27:10 -07:00
sysctl-test.c
sysctl.c mm: allow a controlled amount of unfairness in the page lock 2020-09-17 10:26:41 -07:00
task_work.c task_work: cleanup notification modes 2020-10-17 15:05:30 -06:00
taskstats.c taskstats: move specifying netlink policy back to ops 2020-10-02 19:11:12 -07:00
test_kprobes.c
torture.c torture: Dump ftrace at shutdown only if requested 2020-06-29 12:01:45 -07:00
tracepoint.c tracepoint: Replace zero-length array with flexible-array member 2020-10-29 17:22:59 -05:00
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c usermodehelper: reset umask to default before executing user process 2020-10-06 10:31:52 -07:00
up.c
user-return-notifier.c
user.c user.c: make uidhash_table static 2020-06-04 19:06:24 -07:00
user_namespace.c kernel/: fix repeated words in comments 2020-10-16 11:11:19 -07:00
usermode_driver.c umd: Stop using split_argv 2020-07-07 11:58:59 -05:00
utsname.c nsproxy: add struct nsset 2020-05-09 13:57:12 +02:00
utsname_sysctl.c
watch_queue.c watch_queue: Limit the number of watches a user can hold 2020-08-17 09:39:18 -07:00
watchdog.c kernel/watchdog: fix watchdog_allowed_mask not used warning 2020-11-14 11:26:03 -08:00
watchdog_hld.c
workqueue.c workqueue: fix a kernel-doc warning 2020-10-16 07:28:20 +02:00
workqueue_internal.h