Steven Rostedt (VMware) 3301afbfef ring-buffer: Force before_stamp and write_stamp to be different on discard ... commit 6f6be606e763f2da9fc21de00538c97fe4ca1492 upstream. Part of the logic of the new time stamp code depends on the before_stamp and the write_stamp to be different if the write_stamp does not match the last event on the buffer, as it will be used to calculate the delta of the next event written on the buffer. The discard logic depends on this, as the next event to come in needs to inject a full timestamp as it can not rely on the last event timestamp in the buffer because it is unknown due to events after it being discarded. But by changing the write_stamp back to the time before it, it forces the next event to use a full time stamp, instead of relying on it. The issue came when a full time stamp was used for the event, and rb_time_delta() returns zero in that case. The update to the write_stamp (which subtracts delta) made it not change. Then when the event is removed from the buffer, because the before_stamp and write_stamp still match, the next event written would calculate its delta from the write_stamp, but that would be wrong as the write_stamp is of the time of the event that was discarded. In the case that the delta change being made to write_stamp is zero, set the before_stamp to zero as well, and this will force the next event to inject a full timestamp and not use the current write_stamp. Cc: stable@vger.kernel.org Fixes: a389d86f7f ("ring-buffer: Have nested events still record running time stamp") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-03-09 11:11:12 +01:00
..
bpf	bpf: Clear subreg_def for global function return values	2021-03-04 11:37:34 +01:00
cgroup	cgroup-v1: add disabled controller check in cgroup1_parse_param()	2021-02-17 11:02:25 +01:00
configs
debug	kgdb: fix to kill breakpoints on initmem after boot	2021-03-04 11:38:46 +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	exec: Transform exec_update_mutex into a rw_semaphore	2021-01-09 13:46:24 +01:00
gcov	gcov: add support for GCC 10.1	2020-09-11 09:33:54 -07:00
irq	genirq/msi: Activate Multi-MSI early when MSI_FLAG_ACTIVATE_EARLY is set	2021-02-10 09:29:17 +01:00
kcsan	kcsan: Rewrite kcsan_prandom_u32_max() without prandom_u32_state()	2021-03-04 11:37:37 +01:00
livepatch	kernel/: fix repeated words in comments	2020-10-16 11:11:19 -07:00
locking	locking/lockdep: Avoid unmatched unlock	2021-03-04 11:37:47 +01:00
power	PM: hibernate: flush swap writer after marking	2021-02-03 23:28:40 +01:00
printk	printk: fix deadlock when kernel panic	2021-03-04 11:38:41 +01:00
rcu	rcu/nocb: Perform deferred wake up before last idle's need_resched() check	2021-03-04 11:38:35 +01:00
sched	sched/features: Fix hrtick reprogramming	2021-03-07 12:34:13 +01:00
time	tick/sched: Remove bogus boot "safety" check	2021-01-06 14:56:55 +01:00
trace	ring-buffer: Force before_stamp and write_stamp to be different on discard	2021-03-09 11:11:12 +01:00
.gitignore
acct.c	kernel: acct.c: fix some kernel-doc nits	2020-10-16 11:11:19 -07:00
async.c
audit_fsnotify.c	fsnotify: generalize handle_inode_event()	2020-12-30 11:54:18 +01:00
audit_tree.c	fsnotify: generalize handle_inode_event()	2020-12-30 11:54:18 +01:00
audit_watch.c	fsnotify: generalize handle_inode_event()	2020-12-30 11:54:18 +01:00
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
auditfilter.c	treewide: Use fallthrough pseudo-keyword	2020-08-23 17:36:59 -05:00
auditsc.c
backtracetest.c
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
cpu_pm.c	notifier: Fix broken error handling pattern	2020-09-01 09:58:03 +02:00
cpu.c	kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handling	2020-11-27 00:10:39 +11:00
crash_core.c	kdump: append kernel build-id string to VMCOREINFO	2020-08-12 10:58:01 -07:00
crash_dump.c
cred.c
delayacct.c
dma.c
exec_domain.c
exit.c	kernel/io_uring: cancel io_uring before task works	2021-01-30 13:55:18 +01:00
extable.c
fail_function.c	fail_function: Remove a redundant mutex unlock	2020-11-19 11:58:16 -08:00
fork.c	exec: Transform exec_update_mutex into a rw_semaphore	2021-01-09 13:46:24 +01:00
freezer.c
futex.c	futex: Handle faults correctly for PI futexes	2021-01-30 13:55:17 +01:00
gen_kheaders.sh
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
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	exec: Transform exec_update_mutex into a rw_semaphore	2021-01-09 13:46:24 +01:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c	kcov: make some symbols static	2020-08-12 10:58:02 -07:00
kexec_core.c	kernel: kexec: remove the lock operation of system_transition_mutex	2021-02-03 23:28:37 +01:00
kexec_elf.c
kexec_file.c	ima: Free IMA measurement buffer after kexec syscall	2021-03-04 11:37:50 +01:00
kexec_internal.h
kexec.c	LSM: Introduce kernel_post_load_data() hook	2020-10-05 13:37:03 +02:00
kheaders.c
kmod.c	kmod: remove redundant "be an" in the comment	2020-08-12 10:58:01 -07:00
kprobes.c	kprobes: Fix to delay the kprobes jump optimization	2021-03-04 11:38:35 +01:00
ksysfs.c
kthread.c	kthread: Extract KTHREAD_IS_PER_CPU	2021-02-07 15:37:17 +01:00
latencytop.c
Makefile	kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTORE	2021-03-04 11:38:41 +01:00
module_signature.c
module_signing.c
module-internal.h
module.c	module: Ignore _GLOBAL_OFFSET_TABLE_ when warning for undefined symbols	2021-03-04 11:38:39 +01:00
notifier.c	notifier: Fix broken error handling pattern	2020-09-01 09:58:03 +02:00
nsproxy.c
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_namespace.c	kernel/: fix repeated words in comments	2020-10-16 11:11:19 -07:00
pid.c	exec: Transform exec_update_mutex into a rw_semaphore	2021-01-09 13:46:24 +01:00
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
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: Add missing return in non-void function	2021-03-04 11:38:32 +01:00
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	smp: Process pending softirqs in flush_smp_call_function_from_idle()	2021-03-04 11:37:51 +01:00
smpboot.c	kthread: Extract KTHREAD_IS_PER_CPU	2021-02-07 15:37:17 +01:00
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_ni.c	mm/madvise: introduce process_madvise() syscall: an external memory hinting API	2020-10-18 09:27:10 -07:00
sys.c	kernel/sys.c: fix prototype of prctl_get_tid_address()	2020-10-25 11:44:16 -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
tracepoint.c	tracepoint: Do not fail unregistering a probe due to memory failure	2021-03-04 11:38:03 +01:00
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_namespace.c	kernel/: fix repeated words in comments	2020-10-16 11:11:19 -07:00
user-return-notifier.c
user.c
usermode_driver.c
utsname_sysctl.c
utsname.c
watch_queue.c	watch_queue: Limit the number of watches a user can hold	2020-08-17 09:39:18 -07:00
watchdog_hld.c
watchdog.c	kernel/watchdog: fix watchdog_allowed_mask not used warning	2020-11-14 11:26:03 -08:00
workqueue_internal.h
workqueue.c	workqueue: Restrict affinity change to rescuer	2021-02-07 15:37:17 +01:00