Steven Rostedt (VMware) 34324394f9 tracing/blktrace: Fix to allow setting same value ...

commit 757d914007 upstream.

Masami Hiramatsu reported:

  Current trace-enable attribute in sysfs returns an error
  if user writes the same setting value as current one,
  e.g.

    # cat /sys/block/sda/trace/enable
    0
    # echo 0 > /sys/block/sda/trace/enable
    bash: echo: write error: Invalid argument
    # echo 1 > /sys/block/sda/trace/enable
    # echo 1 > /sys/block/sda/trace/enable
    bash: echo: write error: Device or resource busy

  But this is not a preferred behavior, it should ignore
  if new setting is same as current one. This fixes the
  problem as below.

    # cat /sys/block/sda/trace/enable
    0
    # echo 0 > /sys/block/sda/trace/enable
    # echo 1 > /sys/block/sda/trace/enable
    # echo 1 > /sys/block/sda/trace/enable

Link: http://lkml.kernel.org/r/20180816103802.08678002@gandalf.local.home

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: cd649b8bb8 ("blktrace: remove sysfs_blk_trace_enable_show/store()")
Reported-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2018-09-09 20:04:34 +02:00

..

bpf

bpf: fix references to free_bpf_prog_info() in comments

2018-08-06 16:24:37 +02:00

configs

kconfig: tinyconfig: provide whole choice blocks to avoid warnings

2016-09-24 10:07:42 +02:00

debug

kdb: make "mdr" command repeat

2018-05-30 07:49:17 +02:00

events

perf/core: Fix perf_output_read_group()

2018-05-30 07:49:12 +02:00

gcov

gcov: disable for COMPILE_TEST

2018-01-23 19:50:10 +01:00

irq

genirq: Make force irq threading setup more robust

2018-08-09 12:19:27 +02:00

livepatch

livepatch: x86: fix relocation computation with kASLR

2015-11-11 17:36:04 +01:00

locking

locking/lockdep: Do not record IRQ state within lockdep code

2018-08-24 13:26:55 +02:00

power

PM / hibernate: Fix oops at snapshot_write()

2018-07-17 11:31:46 +02:00

printk

braille-console: Fix value returned by _braille_console_setup

2018-03-22 09:23:23 +01:00

rcu

rcu: Allow for page faults in NMI handlers

2017-10-18 09:20:41 +02:00

sched

sched/rt: Fix rq->clock_update_flags < RQCF_ACT_SKIP warning

2018-05-30 07:49:08 +02:00

time

nohz: Fix local_timer_softirq_pending()

2018-08-09 12:19:27 +02:00

trace

tracing/blktrace: Fix to allow setting same value

2018-09-09 20:04:34 +02:00

.gitignore

certs: add .gitignore to stop git nagging about x509_certificate_list

2015-10-21 15:18:35 +01:00

acct.c

kernel/acct.c: fix the acct->needcheck check in check_free_space()

2018-01-10 09:27:08 +01:00

async.c

kernel/async.c: revert "async: simplify lowest_in_progress()"

2018-02-16 20:09:45 +01:00

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

audit: Fix use after free in audit_remove_watch_rule()

2017-08-24 17:02:35 -07:00

audit.c

audit: return on memory error to avoid null pointer dereference

2018-05-30 07:49:16 +02:00

audit.h

audit: audit_tree_match can be boolean

2015-11-04 08:23:51 -05:00

auditfilter.c

audit: allow not equal op for audit by executable

2018-08-06 16:24:38 +02:00

auditsc.c

audit: allow not equal op for audit by executable

2018-08-06 16:24:38 +02:00

backtracetest.c

…

bounds.c

…

capability.c

exec: Ensure mm->user_ns contains the execed files

2017-01-06 11:16:14 +01:00

cgroup_freezer.c

cgroup: fix handling of multi-destination migration from subtree_control enabling

2015-12-03 10:18:21 -05:00

cgroup_pids.c

cgroup_pids: don't account for the root cgroup

2015-12-03 10:18:21 -05:00

cgroup.c

cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups

2017-04-21 09:30:04 +02:00

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

stable-fixup: hotplug: fix unused function warning

2017-01-12 11:22:48 +01:00

cpuset.c

sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs

2017-10-12 11:27:35 +02:00

crash_dump.c

…

cred.c

cred: Reject inodes with invalid ids in set_create_file_as()

2016-09-15 08:27:49 +02:00

delayacct.c

…

dma.c

…

elfcore.c

…

exec_domain.c

Remove rest of exec domains.

2015-04-12 21:03:31 +02:00

exit.c

kernel/exit.c: avoid undefined behaviour when calling wait4()

2018-05-26 08:48:51 +02:00

extable.c

kernel/extable.c: mark core_kernel_text notrace

2017-07-21 07:44:56 +02:00

fork.c

kaiser: stack map PAGE_SIZE at THREAD_SIZE-PAGE_SIZE

2018-01-05 15:44:23 +01:00

freezer.c

…

futex_compat.c

ptrace: use fsuid, fsgid, effective creds for fs access checks

2016-02-25 12:01:16 -08:00

futex.c

futex: futex_wake_op, fix sign_extend32 sign bits

2018-05-26 08:48:51 +02:00

groups.c

kernel: make groups_sort calling a responsibility group_info allocators

2018-01-10 09:27:10 +01:00

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

treewide: Remove old email address

2015-11-23 09:44:58 +01:00

jump_label.c

jump_label: Invoke jump_label_test() via early_initcall()

2017-12-16 10:33:55 +01:00

kallsyms.c

…

kcmp.c

ptrace: use fsuid, fsgid, effective creds for fs access checks

2016-02-25 12:01:16 -08:00

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: fix double-free when failing to relocate the purgatory

2016-09-24 10:07:36 +02:00

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

kprobes: Make list and blacklist root user read only

2018-09-05 09:18:40 +02:00

ksysfs.c

kexec: split kexec_load syscall from kexec core code

2015-09-10 13:29:01 -07:00

kthread.c

cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups

2017-04-21 09:30:04 +02:00

latencytop.c

…

Makefile

sys_membarrier(): system-wide memory barrier (generic, x86)

2015-09-11 15:21:34 -07:00

membarrier.c

Fix: Disable sys_membarrier when nohz_full is enabled

2017-03-12 06:37:26 +01:00

memremap.c

mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}

2017-01-19 20:17:18 +01:00

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/retpoline: Warn about missing retpoline in module

2018-02-25 11:03:52 +01:00

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

bury struct proc_ns in fs/proc

2014-12-04 14:34:54 -05:00

padata.c

padata: free correct variable

2017-05-20 14:27:02 +02:00

panic.c

kernel/panic.c: add missing \n

2017-07-05 14:37:19 +02:00

params.c

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2015-11-09 15:53:39 -08:00

pid_namespace.c

pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes

2017-05-25 14:30:11 +02:00

pid.c

pidns: disable pid allocation if pid_ns_prepare_proc() is failed in alloc_pid()

2018-04-13 19:50:03 +02:00

profile.c

profile: hide unused functions when !CONFIG_PROC_FS

2018-02-25 11:03:44 +01:00

ptrace.c

ptrace: Properly initialize ptracer_cred on fork

2017-06-14 13:16:20 +02:00

range.c

kernel: avoid overflow in cmp_range

2015-01-17 10:02:23 +13:00

reboot.c

kexec: split kexec_load syscall from kexec core code

2015-09-10 13:29:01 -07:00

relay.c

kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE

2018-05-30 07:49:00 +02:00

resource.c

resource: fix integer overflow at reallocation

2018-04-24 09:32:05 +02:00

seccomp.c

seccomp: Move speculation migitation control to arch code

2018-07-25 10:18:27 +02:00

signal.c

kernel/signal.c: avoid undefined behaviour in kill_something_info

2018-05-30 07:48:52 +02:00

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

Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-02-09 15:24:03 -08:00

stacktrace.c

stacktrace: introduce snprint_stack_trace for buffer output

2014-12-13 12:42:48 -08:00

stop_machine.c

kernel: remove stop_machine() Kconfig dependency

2015-12-12 10:15:34 -08:00

sys_ni.c

mm: mlock: add new mlock system call

2015-11-05 19:34:48 -08:00

sys.c

nospec: Allow getting/setting on non-current task

2018-07-25 10:18:26 +02:00

sysctl_binary.c

fs/coredump: prevent fsuid=0 dumps into user-controlled directories

2016-04-12 09:08:58 -07:00

sysctl.c

sched/sysctl: Check user input value of sysctl_sched_time_avg

2018-09-05 09:18:33 +02:00

task_work.c

task_work: remove fifo ordering guarantee

2015-09-05 13:46:58 -07:00

taskstats.c

netlink: make nlmsg_end() and genlmsg_end() void

2015-01-18 01:03:45 -05:00

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: Do not warn on ENOMEM

2018-05-16 10:06:47 +02:00

tsacct.c

…

uid16.c

kernel: make groups_sort calling a responsibility group_info allocators

2018-01-10 09:27:10 +01:00

up.c

…

user_namespace.c

capabilities: ambient capabilities

2015-09-04 16:54:41 -07:00

user-return-notifier.c

…

user.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2014-12-17 12:31:40 -08:00

utsname_sysctl.c

…

utsname.c

copy address of proc_ns_ops into ns_common

2014-12-04 14:34:47 -05:00

watchdog.c

kernel/watchdog: use nmi registers snapshot in hardlockup handler

2017-01-06 11:16:16 +01:00

workqueue_internal.h

workqueue: Fix NULL pointer dereference

2017-11-15 17:13:11 +01:00

workqueue.c

workqueue: use put_device() instead of kfree()

2018-05-30 07:49:04 +02:00