linux-stable/kernel
Xiao Yang 57f2a2ad73 tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation
commit 0bbe7f7199 upstream.

Traced event can trigger 'snapshot' operation(i.e. calls snapshot_trigger()
or snapshot_count_trigger()) when register_snapshot_trigger() has completed
registration but doesn't allocate buffer for 'snapshot' event trigger.  In
the rare case, 'snapshot' operation always detects the lack of allocated
buffer so make register_snapshot_trigger() allocate buffer first.

trigger-snapshot.tc in kselftest reproduces the issue on slow vm:
-----------------------------------------------------------
cat trace
...
ftracetest-3028  [002] ....   236.784290: sched_process_fork: comm=ftracetest pid=3028 child_comm=ftracetest child_pid=3036
     <...>-2875  [003] ....   240.460335: tracing_snapshot_instance_cond: *** SNAPSHOT NOT ALLOCATED ***
     <...>-2875  [003] ....   240.460338: tracing_snapshot_instance_cond: *** stopping trace here!   ***
-----------------------------------------------------------

Link: http://lkml.kernel.org/r/20200414015145.66236-1-yangx.jy@cn.fujitsu.com

Cc: stable@vger.kernel.org
Fixes: 93e31ffbf4 ("tracing: Add 'snapshot' event trigger command")
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-21 09:03:09 +02:00
..
bpf bpf: Explicitly memset some bpf info structures declared on the stack 2020-04-02 15:28:23 +02:00
cgroup cgroup1: don't call release_agent when it is "" 2020-04-02 15:28:14 +02:00
configs
debug kdb: do a sanity check on the cpu in kdb_per_cpu() 2020-01-27 14:50:48 +01:00
dma dma-debug: add a schedule point in debug_dma_dump_mappings() 2020-01-04 19:12:43 +01:00
events perf/core: Fix mlock accounting in perf_mmap() 2020-02-11 04:34:19 -08:00
gcov
irq genirq/irqdomain: Check pointer in irq_domain_alloc_irqs_hierarchy() 2020-04-17 10:48:41 +02:00
livepatch livepatch: Nullify obj->mod in klp_module_coming()'s error path 2019-10-07 18:57:10 +02:00
locking locking/lockdep: Avoid recursion in lockdep_count_{for,back}ward_deps() 2020-04-17 10:48:42 +02:00
power PM / hibernate: memory_bm_find_bit(): Tighten node optimisation 2020-01-09 10:18:58 +01:00
printk printk: fix exclusive_console replaying 2020-02-11 04:33:51 -08:00
rcu rcu: Avoid data-race in rcu_gp_fqs_check_wake() 2020-02-11 04:33:55 -08:00
sched sched: Avoid scale real weight down to zero 2020-04-17 10:48:40 +02:00
time clocksource: Prevent double add_timer_on() for watchdog_timer 2020-02-11 04:34:18 -08:00
trace tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation 2020-04-21 09:03:09 +02:00
.gitignore
acct.c acct_on(): don't mess with freeze protection 2019-05-31 06:46:05 -07:00
async.c
audit.c audit: always check the netlink payload length in audit_receive_msg() 2020-03-05 16:42:23 +01:00
audit.h
audit_fsnotify.c
audit_tree.c audit: Embed key into chunk 2019-12-13 08:51:11 +01:00
audit_watch.c audit_get_nd(): don't unlock parent too early 2019-12-13 08:51:02 +01:00
auditfilter.c audit: fix error handling in audit_data_to_entry() 2020-03-05 16:42:17 +01:00
auditsc.c audit: print empty EXECVE args 2019-12-01 09:17:17 +01:00
backtracetest.c
bounds.c kbuild: fix kernel/bounds.c 'W=1' warning 2018-11-13 11:08:47 -08:00
capability.c LSM: generalize flag passing to security_capable 2020-01-23 08:21:29 +01:00
compat.c
configs.c
context_tracking.c
cpu.c x86/speculation: Remove redundant arch_smt_update() invocation 2020-04-17 10:48:50 +02:00
cpu_pm.c
crash_core.c kernel/crash_core.c: print timestamp using time64_t 2018-08-22 10:52:47 -07:00
crash_dump.c
cred.c memcg: account security cred as well to kmemcg 2020-01-09 10:19:00 +01:00
delayacct.c
dma.c
elfcore.c kernel/elfcore.c: include proper prototypes 2019-10-11 18:21:23 +02:00
exec_domain.c
exit.c exit: panic before exit_mm() on global init exit 2020-01-09 10:19:02 +01:00
extable.c
fail_function.c
fork.c fork,memcg: alloc_thread_stack_node needs to set tsk->stack 2020-01-27 14:50:58 +01:00
freezer.c PM / reboot: Eliminate race between reboot and suspend 2018-08-06 12:35:20 +02:00
futex.c futex: Unbreak futex hashing 2020-03-25 08:06:14 +01:00
groups.c
hung_task.c kernel: hung_task.c: disable on suspend 2019-04-20 09:16:02 +02:00
iomem.c
irq_work.c irq_work: Do not raise an IPI when queueing work on the local CPU 2019-05-31 06:46:19 -07:00
jump_label.c jump_label: move 'asm goto' support test to Kconfig 2019-06-04 08:02:34 +02:00
kallsyms.c kallsyms: Don't let kallsyms_lookup_size_offset() fail on retrieving the first symbol 2019-09-21 07:17:02 +02:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt kconfig: include kernel/Kconfig.preempt from init/Kconfig 2018-08-02 08:06:54 +09:00
kcov.c kernel/kcov.c: mark write_comp_data() as notrace 2019-02-12 19:47:20 +01:00
kexec.c
kexec_core.c kexec: Allocate decrypted control pages for kdump if SME is enabled 2019-11-24 08:20:29 +01:00
kexec_file.c
kexec_internal.h
kmod.c kmod: make request_module() return an error when autoloading is disabled 2020-04-17 10:48:52 +02:00
kprobes.c kprobes: Fix optimize_kprobe()/unoptimize_kprobe() cancellation logic 2020-03-11 14:14:47 +01:00
ksysfs.c
kthread.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-13 11:25:07 -07:00
latencytop.c
Makefile y2038: futex: Move compat implementation into futex.c 2019-12-01 09:17:38 +01:00
memremap.c mm/memory_hotplug: shrink zones when offlining memory 2020-01-29 16:43:27 +01:00
module-internal.h
module.c module: avoid setting info->name early in case we can fall back to info->mod->name 2020-02-24 08:34:49 +01:00
module_signing.c
notifier.c x86/mm: split vmalloc_sync_all() 2020-03-25 08:06:13 +01:00
nsproxy.c
padata.c padata: always acquire cpu_hotplug_lock before pinst->lock 2020-04-13 10:45:05 +02:00
panic.c kernel/panic.c: do not append newline to the stack protector panic string 2019-12-01 09:17:10 +01:00
params.c
pid.c Fix failure path in alloc_pid() 2019-01-13 09:51:06 +01:00
pid_namespace.c signal/pid_namespace: Fix reboot_pid_ns to use send_sig not force_sig 2019-07-26 09:14:01 +02:00
profile.c
ptrace.c ptrace: reintroduce usage of subjective credentials in ptrace_has_cap() 2020-01-23 08:21:29 +01:00
range.c
reboot.c PM / reboot: Eliminate race between reboot and suspend 2018-08-06 12:35:20 +02:00
relay.c relay: check return of create_buf_file() properly 2019-03-13 14:02:35 -07:00
resource.c resource: fix locking in find_next_iomem_res() 2019-09-16 08:22:20 +02:00
rseq.c
seccomp.c LSM: generalize flag passing to security_capable 2020-01-23 08:21:29 +01:00
signal.c signal: Extend exec_id to 64bits 2020-04-17 10:48:47 +02:00
smp.c cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM 2019-02-12 19:47:25 +01:00
smpboot.c
smpboot.h
softirq.c nohz: Fix missing tick reprogram when interrupting an inline softirq 2018-08-03 15:52:10 +02:00
stacktrace.c
stop_machine.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-08-13 11:25:07 -07:00
sys.c kernel/sys.c: prctl: fix false positive in validate_prctl_map() 2019-06-15 11:54:01 +02:00
sys_ni.c
sysctl.c kernel: sysctl: make drop_caches write-only 2020-01-04 19:13:17 +01:00
sysctl_binary.c
task_work.c
taskstats.c taskstats: fix data-race 2020-01-09 10:18:59 +01:00
test_kprobes.c
torture.c
tracepoint.c tracepoint: Fix tracepoint array element size mismatch 2018-10-17 15:35:29 -04:00
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c
up.c
user-return-notifier.c
user.c userns: use irqsave variant of refcount_dec_and_lock() 2018-08-22 10:52:47 -07:00
user_namespace.c userns: also map extents in the reverse map to kernel IDs 2018-11-13 11:09:00 -08:00
utsname.c
utsname_sysctl.c sys: don't hold uts_sem while accessing userspace memory 2018-08-11 02:05:53 -05:00
watchdog.c watchdog/softlockup: Enforce that timestamp is valid on boot 2020-02-24 08:34:49 +01:00
watchdog_hld.c watchdog: Mark watchdog touch functions as notrace 2018-08-30 12:56:40 +02:00
workqueue.c workqueue: don't use wq_select_unbound_cpu() for bound works 2020-03-18 07:14:20 +01:00
workqueue_internal.h