Andy Lutomirski e45cdc71d1 membarrier: Execute SYNC_CORE on the calling thread ... membarrier()'s MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE is documented as syncing the core on all sibling threads but not necessarily the calling thread. This behavior is fundamentally buggy and cannot be used safely. Suppose a user program has two threads. Thread A is on CPU 0 and thread B is on CPU 1. Thread A modifies some text and calls membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE). Then thread B executes the modified code. If, at any point after membarrier() decides which CPUs to target, thread A could be preempted and replaced by thread B on CPU 0. This could even happen on exit from the membarrier() syscall. If this happens, thread B will end up running on CPU 0 without having synced. In principle, this could be fixed by arranging for the scheduler to issue sync_core_before_usermode() whenever switching between two threads in the same mm if there is any possibility of a concurrent membarrier() call, but this would have considerable overhead. Instead, make membarrier() sync the calling CPU as well. As an optimization, this avoids an extra smp_mb() in the default barrier-only mode and an extra rseq preempt on the caller. 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> Link: https://lore.kernel.org/r/250ded637696d490c69bef1877148db86066881c.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: Execute SYNC_CORE on the calling thread	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	…
Kconfig.freezer	…
Kconfig.hz	…
Kconfig.locks	…
Kconfig.preempt	…
Makefile	Kbuild updates for v5.10	2020-10-22 13:13:57 -07:00
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	…
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	…
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	…