milos-linux/kernel
Steven Rostedt a254b6d13b ring-buffer: Fix reporting of missed events in iterator
When tracing is active while reading the trace file, if the iterator
reading the buffer detects that the writer has passed the iterator head,
it will reset and set a "missed events" flag. This flag is passed to the
output processing to show the user that events were missed:

  CPU:4 [LOST EVENTS]

The problem is that the flag is reset after it is checked in
ring_buffer_iter_dropped(). But the "trace" file iterates over all the CPU
ring buffers and it will check if they are dropped when figuring out which
buffer to print next. This prematurely clears the missed_events flag if
the CPU buffer with the missed events is not the one that is printed next.

On the iteration where the CPU buffer with the missed events is printed,
the check if it had missed events would return false and the output does
not show that events were missed.

Do not reset the missed_events flag when checking if there were missed
events, but instead clear it when moving the iterator head to the next
event.

Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260520220801.4fd09d13@fedora
Fixes: c9b7a4a72f ("ring-buffer/tracing: Have iterator acknowledge dropped events")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-05-21 08:20:29 -04:00
..
bpf bpf: Fix off-by-one boundary validation in arena direct-value access 2026-05-09 16:18:39 -07:00
cgroup cgroup: Fixes for v7.1-rc3 2026-05-13 14:56:31 -07:00
configs Remove WARN_ALL_UNSEEDED_RANDOM kernel config option 2026-02-23 11:18:48 -08:00
debug kgdb: update outdated references to kgdb_wait() 2026-04-21 16:41:54 +01:00
dma memblock: updates for 7.0-rc1 2026-04-18 11:29:14 -07:00
entry arm64 updates for 7.1: 2026-04-14 16:48:56 -07:00
events perf/core: Fix deadlock in perf_mmap() failure path 2026-05-05 12:47:20 +02:00
futex futex: Prevent lockup in requeue-PI during signal/ timeout wakeup 2026-04-29 08:56:40 +02:00
gcov Convert more 'alloc_obj' cases to default GFP_KERNEL arguments 2026-02-21 20:03:00 -08:00
irq genirq/chip: Don't call add_interrupt_randomness() for NMIs 2026-05-11 14:56:04 +02:00
kcsan kcsan: test: Adjust "expect" allocation type for kmalloc_obj 2026-02-26 09:54:08 -08:00
livepatch Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
liveupdate liveupdate fixes for v7.1-rc4 2026-05-13 08:24:50 -07:00
locking locking/mutex: Fix ww_mutex wait_list operations 2026-04-23 10:05:49 +02:00
module module: Simplify warning on positive returns from module_init() 2026-04-04 00:04:48 +00:00
power Merge branches 'pm-cpuidle', 'pm-opp' and 'pm-sleep' 2026-04-10 12:37:27 +02:00
printk Merge branch 'rework/prb-fixes' into for-linus 2026-04-20 13:42:01 +02:00
rcu RCU changes for v7.1 2026-04-13 09:36:45 -07:00
sched sched_ext: Fixes for v7.1-rc3 2026-05-13 15:00:40 -07:00
time timers/migration: Fix another hotplug activation race 2026-05-06 08:21:12 +02:00
trace ring-buffer: Fix reporting of missed events in iterator 2026-05-21 08:20:29 -04:00
unwind Convert more 'alloc_obj' cases to default GFP_KERNEL arguments 2026-02-21 20:03:00 -08:00
.gitignore
acct.c vfs-7.1-rc1.misc 2026-04-13 14:20:11 -07:00
async.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
audit.c audit: enforce AUDIT_LOCKED for AUDIT_TRIM and AUDIT_MAKE_EQUIV 2026-05-12 16:10:38 -04:00
audit.h audit: widen ino fields to u64 2026-03-06 14:31:26 +01:00
audit_fsnotify.c audit: widen ino fields to u64 2026-03-06 14:31:26 +01:00
audit_tree.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
audit_watch.c audit: widen ino fields to u64 2026-03-06 14:31:26 +01:00
auditfilter.c audit: fix coding style issues 2026-03-05 22:16:08 -05:00
auditsc.c audit: fix incorrect inheritable capability in CAPSET records 2026-05-12 16:05:57 -04:00
backtracetest.c
bounds.c x86/asm: Remove ANNOTATE_DATA_SPECIAL usage 2025-12-03 16:53:19 +01:00
capability.c
cfi.c
compat.c
configs.c
context_tracking.c context_tracking: Remove rcu_task_trace_heavyweight_{enter,exit}() 2026-01-01 16:39:46 +08:00
cpu.c SPDX updates for 7.0-rc1 2026-02-17 09:46:03 -08:00
cpu_pm.c
crash_core.c kernel/crash: remove inclusion of crypto/sha1.h 2026-03-27 21:19:46 -07:00
crash_core_test.c
crash_dump_dm_crypt.c crash_dump/dm-crypt: don't print in arch-specific code 2026-04-02 23:36:24 -07:00
crash_reserve.c kernel/crash: remove inclusion of crypto/sha1.h 2026-03-27 21:19:46 -07:00
cred.c cred: remove unused set_security_override_from_ctx() 2026-01-06 20:52:57 -05:00
delayacct.c delayacct: fix uapi timespec64 definition 2026-02-08 00:13:32 -08:00
dma.c
elfcorehdr.c
exec_domain.c
exit.c ptrace: slightly saner 'get_dumpable()' logic 2026-05-14 08:32:11 -07:00
exit.h
extable.c
fail_function.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
fork.c futex: Drop CLONE_THREAD requirement for private default hash alloc 2026-05-01 13:12:34 -07:00
freezer.c
gen_kheaders.sh
groups.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
hung_task.c hung_task: explicitly report I/O wait state in log output 2026-03-27 21:19:40 -07:00
iomem.c
irq_work.c irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT 2026-05-11 16:28:04 +02:00
jump_label.c jump_label: use ATOMIC_INIT() for initialization of .enabled 2026-03-16 13:16:48 +01:00
kallsyms.c mm.git review status for linus..mm-nonmm-stable 2026-02-12 12:13:01 -08:00
kallsyms_internal.h kallsyms: Get rid of kallsyms relative base 2026-01-22 15:58:22 -07:00
kallsyms_selftest.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kallsyms_selftest.h
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.kexec
Kconfig.locks
Kconfig.preempt sched: Further restrict the preemption modes 2026-01-08 12:43:57 +01:00
kcov.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kexec.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
kexec_core.c kernel/kexec: remove inclusion of crypto/hash.h 2026-03-27 21:19:46 -07:00
kexec_elf.c
kexec_file.c kexec: derive purgatory entry from symbol 2026-01-31 16:16:07 -08:00
kexec_internal.h
kheaders.c
kprobes.c kprobes: Remove unneeded warnings from __arm_kprobe_ftrace() 2026-03-13 23:15:26 +09:00
kstack_erase.c
ksyms_common.c
ksysfs.c kernel: ksysfs: initialize kernel_kobj earlier 2026-04-03 19:39:52 +02:00
kthread.c kthread: consolidate kthread exit paths to prevent use-after-free 2026-02-26 10:45:49 +01:00
latencytop.c
Makefile kcov: Enable context analysis 2026-01-05 16:43:34 +01:00
module_signature.c module: Give 'enum pkey_id_type' a more specific name 2026-03-24 21:42:37 +00:00
notifier.c
nscommon.c nsfs: tighten permission checks for ns iteration ioctls 2026-02-27 22:00:08 +01:00
nsproxy.c vfs-7.1-rc1.mount.v2 2026-04-14 19:59:25 -07:00
nstree.c nstree: tighten permission checks for listing 2026-02-27 22:00:11 +01:00
padata.c padata: Put CPU offline callback in ONLINE section to allow failure 2026-03-22 11:17:59 +09:00
panic.c kernel/panic: mark init_taint_buf as __initdata and panic instead of warning in alloc_taint_buf() 2026-03-27 21:19:33 -07:00
params.c module: Clean up parse_args() arguments 2026-03-18 21:43:18 +00:00
pid.c mm.git review status for linus..mm-nonmm-stable 2026-04-16 20:11:56 -07:00
pid_namespace.c pid_namespace: allow opening pid_for_children before init was created 2026-03-20 14:44:26 +01:00
pid_sysctl.h
profile.c
ptrace.c ptrace: slightly saner 'get_dumpable()' logic 2026-05-14 08:32:11 -07:00
range.c
reboot.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
regset.c
relay.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
resource.c PCI: Align head space better 2026-03-27 10:19:08 -05:00
resource_kunit.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
rseq.c rseq: Reenable performance optimizations conditionally 2026-05-06 17:40:27 +02:00
scftorture.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
scs.c
seccomp.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
signal.c mm.git review status for linus..mm-nonmm-stable 2026-04-16 20:11:56 -07:00
smp.c tracing updates for v7.1: 2026-04-17 09:43:12 -07:00
smpboot.c
smpboot.h
softirq.c softirq: Prepare for deferred hrtimer rearming 2026-02-27 16:40:13 +01:00
stacktrace.c
static_call.c
static_call_inline.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
stop_machine.c
sys.c prctl: cfi: change the branch landing pad prctl()s to be more descriptive 2026-04-04 18:40:58 -06:00
sys_ni.c rseq: Implement sys_rseq_slice_yield() 2026-01-22 11:11:17 +01:00
sysctl-test.c
sysctl.c sysctl: fix uninitialized variable in proc_do_large_bitmap 2026-03-26 09:32:19 +01:00
task_work.c
taskstats.c taskstats: set version in TGID exit notifications 2026-04-15 02:15:02 -07:00
torture.c torture: Avoid modulo-zero error in torture_hrtimeout_ns() 2026-03-30 15:48:14 -04:00
tracepoint.c tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func() 2026-04-14 05:17:02 -04:00
tsacct.c tsacct: skip all kernel threads 2026-01-26 19:07:13 -08:00
ucount.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
uid16.c
uid16.h
umh.c treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
up.c
user-return-notifier.c
user.c
user_namespace.c Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses 2026-02-22 08:26:33 -08:00
utsname.c
utsname_sysctl.c
vhost_task.c Convert 'alloc_obj' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
vmcore_info.c mm.git review status for linus..mm-nonmm-stable 2026-04-16 20:11:56 -07:00
watch_queue.c Convert 'alloc_flex' family to use the new default GFP_KERNEL argument 2026-02-21 17:09:51 -08:00
watchdog.c watchdog/hardlockup: improve buddy system detection timeliness 2026-03-27 21:19:47 -07:00
watchdog_buddy.c watchdog/hardlockup: improve buddy system detection timeliness 2026-03-27 21:19:47 -07:00
watchdog_perf.c watchdog/hardlockup: simplify perf event probe and remove per-cpu dependency 2026-02-08 00:13:35 -08:00
workqueue.c workqueue: Fix wq->cpu_pwq leak in alloc_and_link_pwqs() WQ_UNBOUND path 2026-05-08 07:59:44 -10:00
workqueue_internal.h workqueue: Show in-flight work item duration in stall diagnostics 2026-03-05 07:27:48 -10:00