Steven Rostedt (Google) ea82edad0a tracing: Do not free snapshot if tracer is on cmdline ... [ Upstream commit a541a9559bb0a8ecc434de01d3e4826c32e8bb53 ] The ftrace_boot_snapshot and alloc_snapshot cmdline options allocate the snapshot buffer at boot up for use later. The ftrace_boot_snapshot in particular requires the snapshot to be allocated because it will take a snapshot at the end of boot up allowing to see the traces that happened during boot so that it's not lost when user space takes over. When a tracer is registered (started) there's a path that checks if it requires the snapshot buffer or not, and if it does not and it was allocated it will do a synchronization and free the snapshot buffer. This is only required if the previous tracer was using it for "max latency" snapshots, as it needs to make sure all max snapshots are complete before freeing. But this is only needed if the previous tracer was using the snapshot buffer for latency (like irqoff tracer and friends). But it does not make sense to free it, if the previous tracer was not using it, and the snapshot was allocated by the cmdline parameters. This basically takes away the point of allocating it in the first place! Note, the allocated snapshot worked fine for just trace events, but fails when a tracer is enabled on the cmdline. Further investigation, this goes back even further and it does not require a tracer on the cmdline to fail. Simply enable snapshots and then enable a tracer, and it will remove the snapshot. Link: https://lkml.kernel.org/r/20221005113757.041df7fe@gandalf.local.home Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: stable@vger.kernel.org Fixes: 45ad21ca55 ("tracing: Have trace_array keep track if snapshot buffer is allocated") Reported-by: Ross Zwisler <zwisler@kernel.org> Tested-by: Ross Zwisler <zwisler@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2022-10-30 09:41:18 +01:00
..
bpf	bpf: Ensure correct locking around vulnerable function find_vpid()	2022-10-26 13:25:21 +02:00
cgroup	cgroup/cpuset: Enable update_tasks_cpumask() on top_cpuset	2022-10-26 13:25:41 +02:00
configs
debug	lockdown: also lock down previous kgdb use	2022-05-30 09:33:22 +02:00
dma	swiotlb: max mapping size takes min align mask into account	2022-10-05 10:38:40 +02:00
entry	KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guest	2021-10-06 15:55:49 +02:00
events	perf/core: Fix data race between perf_event_set_output() and perf_mmap_close()	2022-07-29 17:19:11 +02:00
gcov	gcov: support GCC 12.1 and newer compilers	2022-10-26 13:25:56 +02:00
irq	genirq: GENERIC_IRQ_IPI depends on SMP	2022-08-21 15:15:28 +02:00
kcsan	kcsan: Fix debugfs initcall return type	2021-05-26 12:06:54 +02:00
livepatch	livepatch: fix race between fork and KLP transition	2022-10-26 13:25:14 +02:00
locking	locking/lockdep: Fix lockdep_init_map_*() confusion	2022-08-21 15:15:33 +02:00
power	PM: hibernate: defer device probing when resuming from hibernation	2022-08-21 15:15:31 +02:00
printk	printk: fix return value of printk.devkmsg __setup handler	2022-04-08 14:40:08 +02:00
rcu	rcu-tasks: Convert RCU_LOCKDEP_WARN() to WARN_ONCE()	2022-10-26 13:25:44 +02:00
sched	sched/fair: Fix fault in reweight_entity	2022-08-21 15:16:26 +02:00
time	timekeeping: contribute wall clock to rng on time change	2022-08-21 15:16:20 +02:00
trace	tracing: Do not free snapshot if tracer is on cmdline	2022-10-30 09:41:18 +01:00
.gitignore	kbuild: update config_data.gz only when the content of .config is changed	2021-05-11 14:47:37 +02:00
acct.c	kernel: acct.c: fix some kernel-doc nits	2020-10-16 11:11:19 -07:00
async.c	Revert "module, async: async_synchronize_full() on module init iff async is used"	2022-02-23 12:01:00 +01:00
audit_fsnotify.c	audit: fix potential double free on error path from fsnotify_add_inode_mark	2022-08-31 17:15:13 +02:00
audit_tree.c	audit: move put_tree() to avoid trim_trees refcount underflow and UAF	2021-09-03 10:09:31 +02:00
audit_watch.c	fsnotify: generalize handle_inode_event()	2020-12-30 11:54:18 +01:00
audit.c	audit: improve audit queue handling when "audit=1" on cmdline	2022-02-08 18:30:34 +01:00
audit.h	audit: log AUDIT_TIME_* records only from rules	2022-04-08 14:40:00 +02:00
auditfilter.c
auditsc.c	audit: log AUDIT_TIME_* records only from rules	2022-04-08 14:40:00 +02:00
backtracetest.c
bounds.c
capability.c	LSM: Signal to SafeSetID when setting group IDs	2020-10-13 09:17:34 -07:00
compat.c
configs.c
context_tracking.c
cpu_pm.c	PM: cpu: Make notifier chain use a raw_spinlock_t	2021-09-15 09:50:40 +02:00
cpu.c	random: clear fast pool, crng, and batches in cpuhp bring up	2022-05-30 09:33:36 +02:00
crash_core.c	crash_core, vmcoreinfo: append 'SECTION_SIZE_BITS' to vmcoreinfo	2021-06-23 14:42:52 +02:00
crash_dump.c
cred.c	Revert "Add a reference to ucounts for each cred"	2021-09-08 08:49:00 +02:00
delayacct.c
dma.c
exec_domain.c
exit.c	fix race between exit_itimers() and /proc/pid/timers	2022-07-21 21:19:59 +02:00
extable.c
fail_function.c	fail_function: Remove a redundant mutex unlock	2020-11-19 11:58:16 -08:00
fork.c	IB/core: Fix a nested dead lock as part of ODP flow	2022-09-15 11:32:05 +02:00
freezer.c	Revert "kernel: freezer should treat PF_IO_WORKER like PF_KTHREAD for freezing"	2021-04-07 15:00:14 +02:00
futex.c	mm, futex: fix shared futex pgoff on shmem huge page	2021-06-30 08:47:29 -04:00
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	jump_label: Fix jump_label_text_reserved() vs __init	2021-07-20 16:05:58 +02:00
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
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: force signature verification when CONFIG_KEXEC_SIG is configured	2022-07-21 21:20:11 +02:00
kexec_internal.h
kexec.c	LSM: Introduce kernel_post_load_data() hook	2020-10-05 13:37:03 +02:00
kheaders.c
kmod.c
kprobes.c	kprobes: Prohibit probes in gate area	2022-09-15 11:32:03 +02:00
ksysfs.c
kthread.c	kthread: Fix PF_KTHREAD vs to_kthread() race	2021-09-03 10:09:31 +02:00
latencytop.c
Makefile	kbuild: update config_data.gz only when the content of .config is changed	2021-05-11 14:47:37 +02:00
module_signature.c	module: harden ELF info handling	2021-03-25 09:04:11 +01:00
module_signing.c	module: harden ELF info handling	2021-03-25 09:04:11 +01:00
module-internal.h
module.c	module: check for exit sections in layout_sections() instead of module_init_section()	2022-05-25 09:18:02 +02:00
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	memcg: enable accounting for pids in nested pid namespaces	2021-09-18 13:40:36 +02:00
pid.c	exec: Transform exec_update_mutex into a rw_semaphore	2021-01-09 13:46:24 +01:00
profile.c	profiling: fix shift too large makes kernel panic	2022-08-21 15:16:05 +02:00
ptrace.c	ptrace: Reimplement PTRACE_KILL by always sending SIGKILL	2022-06-09 10:20:49 +02:00
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 walk_mem_res() find all busy IORESOURCE_MEM resources	2021-05-19 10:13:09 +02:00
rseq.c	rseq: Remove broken uapi field layout on 32-bit little endian	2022-04-08 14:40:03 +02:00
scftorture.c	scftorture: Fix distribution of short handler delays	2022-06-09 10:21:01 +02:00
scs.c
seccomp.c	seccomp: Fix setting loaded filter count during TSYNC	2021-08-18 08:59:06 +02:00
signal.c	signal handling: don't use BUG_ON() for debugging	2022-07-21 21:20:18 +02:00
smp.c	smp: Fix offline cpu check in flush_smp_call_function_queue()	2022-04-20 09:23:29 +02:00
smpboot.c	sched/core: Initialize the idle task with preemption disabled	2021-07-14 16:55:50 +02:00
smpboot.h
softirq.c	softirq: Add debug check to __raise_softirq_irqoff()	2020-09-16 15:18:56 +02:00
stackleak.c	gcc-plugins/stackleak: Use noinstr in favor of notrace	2022-02-23 12:01:00 +01:00
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 unused variable warn w/o MODULE	2021-09-08 08:49:00 +02:00
stop_machine.c	stop_machine, rcu: Mark functions as notrace	2020-10-26 12:12:27 +01:00
sys_ni.c	kernel/sys_ni: add compat entry for fadvise64_64	2022-08-31 17:15:13 +02:00
sys.c	prctl: allow to setup brk for et_dyn executables	2021-09-26 14:08:57 +02:00
sysctl-test.c
sysctl.c	mm: sysctl: fix missing numa_stat when !CONFIG_HUGETLB_PAGE	2022-07-21 21:20:13 +02:00
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: Use rcu get state and cond sync for static call updates	2021-09-03 10:09:30 +02:00
tsacct.c	taskstats: Cleanup the use of task->exit_code	2022-01-27 10:54:33 +01:00
ucount.c	Revert "Add a reference to ucounts for each cred"	2021-09-08 08:49:00 +02:00
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	smp: Fix smp_call_function_single_async prototype	2021-05-14 09:50:46 +02:00
user_namespace.c	Revert "Add a reference to ucounts for each cred"	2021-09-08 08:49:00 +02:00
user-return-notifier.c
user.c
usermode_driver.c	bpf: Fix umd memory leak in copy_process()	2021-03-30 14:32:03 +02:00
utsname_sysctl.c
utsname.c
watch_queue.c	watch_queue: Fix missing locking in add_watch_to_object()	2022-08-03 12:00:44 +02:00
watchdog_hld.c
watchdog.c	watchdog: export lockup_detector_reconfigure	2022-08-25 11:38:20 +02:00
workqueue_internal.h
workqueue.c	workqueue: don't skip lockdep work dependency in cancel_work_sync()	2022-09-28 11:10:40 +02:00