Steven Rostedt (Red Hat) b7ffffbb46 ftrace: Add infrastructure for delayed enabling of module functions ... Qiu Peiyang pointed out that there's a race when enabling function tracing and loading a module. In order to make the modifications of converting nops in the prologue of functions into callbacks, the text needs to be converted from read-only to read-write. When enabling function tracing, the text permission is updated, the functions are modified, and then they are put back. When loading a module, the updates to convert function calls to mcount is done before the module text is set to read-only. But after it is done, the module text is visible by the function tracer. Thus we have the following race: CPU 0 CPU 1 ----- ----- start function tracing set text to read-write load_module add functions to ftrace set module text read-only update all functions to callbacks modify module functions too < Can't it's read-only > When this happens, ftrace detects the issue and disables itself till the next reboot. To fix this, a new DISABLED flag is added for ftrace records, which all module functions get when they are added. Then later, after the module code is all set, the records will have the DISABLED flag cleared, and they will be enabled if any callback wants all functions to be traced. Note, this doesn't add the delay to later. It simply changes the ftrace_module_init() to do both the setting of DISABLED records, and then immediately calls the enable code. This helps with testing this new code as it has the same behavior as previously. Another change will come after this to have the ftrace_module_enable() called after the text is set to read-only. Cc: Qiu Peiyang <peiyangx.qiu@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>		2016-01-07 15:40:01 -05:00
..
bpf	bpf, verifier: annotate verbose printer with __printf	2015-11-03 11:29:56 -05:00
configs	kconfig: add xenconfig defconfig helper	2015-06-16 11:04:29 +01:00
debug	debug: prevent entering debug mode on panic/exception.	2015-02-19 12:39:03 -06:00
events	Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-11-15 09:36:24 -08:00
gcov	gcov: add support for GCC 5.1	2015-06-30 19:44:57 -07:00
irq	Merge branches 'irq-urgent-for-linus' and 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-11-15 09:30:48 -08:00
livepatch	livepatch: x86: fix relocation computation with kASLR	2015-11-11 17:36:04 +01:00
locking	mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd	2015-11-06 17:50:42 -08:00
power	mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM	2015-11-06 17:50:42 -08:00
printk	printk: prevent userland from spoofing kernel messages	2015-11-06 17:50:42 -08:00
rcu	Merge branches 'doc.2015.10.06a', 'percpu-rwsem.2015.10.06a' and 'torture.2015.10.06a' into HEAD	2015-10-07 16:06:25 -07:00
sched	Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-11-15 09:35:33 -08:00
time	Merge branches 'irq-urgent-for-linus' and 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-11-15 09:30:48 -08:00
trace	ftrace: Add infrastructure for delayed enabling of module functions	2016-01-07 15:40:01 -05:00
.gitignore	certs: add .gitignore to stop git nagging about x509_certificate_list	2015-10-21 15:18:35 +01:00
acct.c	acct: check FMODE_CAN_WRITE	2015-04-11 22:27:55 -04:00
async.c
audit_fsnotify.c	audit: clean simple fsnotify implementation	2015-08-06 16:14:53 -04:00
audit_tree.c	audit: audit_tree_match can be boolean	2015-11-04 08:23:51 -05:00
audit_watch.c	Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit	2015-09-08 13:34:59 -07:00
audit.c	mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd	2015-11-06 17:50:42 -08:00
audit.h	audit: audit_tree_match can be boolean	2015-11-04 08:23:51 -05:00
auditfilter.c	audit: fix comment block whitespace	2015-11-04 08:23:51 -05:00
auditsc.c	Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit	2015-09-08 13:34:59 -07:00
backtracetest.c
bounds.c
capability.c	kernel: conditionally support non-root users, groups and capabilities	2015-04-15 16:35:22 -07:00
cgroup_freezer.c	cgroup: allow a cgroup subsystem to reject a fork	2015-07-14 17:29:23 -04:00
cgroup_pids.c	cgroup: add cgroup_subsys->free() method and use it to fix pids controller	2015-10-15 16:41:53 -04:00
cgroup.c	mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd	2015-11-06 17:50:42 -08:00
compat.c	compat: cleanup coding in compat_get_bitmap() and compat_put_bitmap()	2015-06-04 23:57:18 +02:00
configs.c
context_tracking.c	context_tracking: avoid irq_save/irq_restore on guest entry and exit	2015-11-10 12:06:23 +01:00
cpu_pm.c	kernel/cpu_pm: fix cpu_cluster_pm_exit comment	2015-09-03 02:42:20 +02:00
cpu.c	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-11-03 18:03:50 -08:00
cpuset.c	Merge branch 'akpm' (patches from Andrew)	2015-11-05 23:10:54 -08:00
crash_dump.c
cred.c	kernel/cred.c: remove unnecessary kdebug atomic reads	2015-09-10 13:29:01 -07:00
delayacct.c
dma.c
elfcore.c
exec_domain.c	Remove rest of exec domains.	2015-04-12 21:03:31 +02:00
exit.c	Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-11-03 18:03:50 -08:00
extable.c	kernel/extable.c: remove duplicated include	2015-09-10 13:29:01 -07:00
fork.c	Merge branch 'akpm' (patches from Andrew)	2015-11-05 23:10:54 -08:00
freezer.c
futex_compat.c
futex.c	driver core update for 4.4-rc1	2015-11-04 21:50:37 -08:00
groups.c	kernel: conditionally support non-root users, groups and capabilities	2015-04-15 16:35:22 -07:00
hung_task.c	kernel/hung_task.c: change hung_task.c to use for_each_process_thread()	2015-04-15 16:35:22 -07:00
irq_work.c
jump_label.c	locking/static_keys: Add selftest	2015-08-03 11:34:16 +02:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks	locking/qrwlock: Rename QUEUE_RWLOCK to QUEUED_RWLOCKS	2015-05-12 09:46:00 +02:00
Kconfig.preempt
kexec_core.c	kexec: use file name as the output message prefix	2015-11-06 17:50:42 -08:00
kexec_file.c	kexec: use file name as the output message prefix	2015-11-06 17:50:42 -08:00
kexec_internal.h	kexec: split kexec_file syscall code to kexec_file.c	2015-09-10 13:29:01 -07:00
kexec.c	kexec: use file name as the output message prefix	2015-11-06 17:50:42 -08:00
kmod.c	kmod: don't run async usermode helper as a child of kworker thread	2015-10-23 17:55:10 +09:00
kprobes.c	perf/x86/hw_breakpoints: Disallow kernel breakpoints unless kprobe-safe	2015-08-04 10:16:54 +02:00
ksysfs.c	kexec: split kexec_load syscall from kexec core code	2015-09-10 13:29:01 -07:00
kthread.c	kernel/kthread.c:kthread_create_on_node(): clarify documentation	2015-09-04 16:54:41 -07:00
latencytop.c
Makefile	sys_membarrier(): system-wide memory barrier (generic, x86)	2015-09-11 15:21:34 -07:00
membarrier.c	sys_membarrier(): system-wide memory barrier (generic, x86)	2015-09-11 15:21:34 -07:00
memremap.c	libnvdimm for 4.4:	2015-11-10 12:07:22 -08:00
module_signing.c	KEYS: Merge the type-specific data with the payload data	2015-10-21 15:18:36 +01:00
module-internal.h
module.c	module: Fix locking in symbol_put_addr()	2015-08-24 10:37:01 +09:30
notifier.c	Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2015-09-01 08:40:25 -07:00
nsproxy.c
padata.c	padata: use %*pb[l] to print bitmaps including cpumasks and nodemasks	2015-02-13 21:21:38 -08:00
panic.c	kernel/panic.c: turn off locks debug before releasing console lock	2015-11-20 16:17:32 -08:00
params.c	Nothing exciting, minor tweaks and cleanups.	2015-11-09 15:53:39 -08:00
pid_namespace.c
pid.c	rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN()	2015-07-22 15:27:32 -07:00
profile.c	mm: rename alloc_pages_exact_node() to __alloc_pages_node()	2015-09-08 15:35:28 -07:00
ptrace.c	seccomp, ptrace: add support for dumping seccomp filters	2015-10-27 19:55:13 -07:00
range.c
reboot.c	kexec: split kexec_load syscall from kexec core code	2015-09-10 13:29:01 -07:00
relay.c	kernel/relay.c: use kvfree() in relay_free_page_array()	2015-06-30 19:44:59 -07:00
resource.c	mm: enhance region_is_ram() to region_intersects()	2015-08-10 23:07:05 -04:00
seccomp.c	seccomp, ptrace: add support for dumping seccomp filters	2015-10-27 19:55:13 -07:00
signal.c	kernel/signal.c: unexport sigsuspend()	2015-11-20 16:17:32 -08:00
smp.c	mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd	2015-11-06 17:50:42 -08:00
smpboot.c	stop_machine: Kill smp_hotplug_thread->pre_unpark, introduce stop_machine_unpark()	2015-10-20 10:23:55 +02:00
smpboot.h
softirq.c
stacktrace.c
stop_machine.c	sched: Move cpu_active() tests from stop_two_cpus() into migrate_swap_stop()	2015-10-20 10:25:56 +02:00
sys_ni.c	mm: mlock: add new mlock system call	2015-11-05 19:34:48 -08:00
sys.c	pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode	2015-11-06 17:50:42 -08:00
sysctl_binary.c
sysctl.c	kernel/watchdog.c: add sysctl knob hardlockup_panic	2015-11-05 19:34:48 -08:00
task_work.c	task_work: remove fifo ordering guarantee	2015-09-05 13:46:58 -07:00
taskstats.c
test_kprobes.c
torture.c	torture: Consolidate cond_resched_rcu_qs() into stutter_wait()	2015-10-06 11:25:01 -07:00
tracepoint.c	tracepoint: Give priority to probes of tracepoints	2015-10-25 21:33:54 -04:00
tsacct.c
uid16.c
up.c
user_namespace.c	capabilities: ambient capabilities	2015-09-04 16:54:41 -07:00
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
watchdog.c	kernel/watchdog.c: fix race between proc_watchdog_thresh() and watchdog_timer_fn()	2015-11-05 19:34:48 -08:00
workqueue_internal.h
workqueue.c	Merge branch 'for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq	2015-11-05 14:16:27 -08:00