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Eiichi Tsukata 46cc0b4442 tracing/snapshot: Resize spare buffer if size changed 
Current snapshot implementation swaps two ring_buffers even though their
sizes are different from each other, that can cause an inconsistency
between the contents of buffer_size_kb file and the current buffer size.

For example:

  # cat buffer_size_kb
  7 (expanded: 1408)
  # echo 1 > events/enable
  # grep bytes per_cpu/cpu0/stats
  bytes: 1441020
  # echo 1 > snapshot             // current:1408, spare:1408
  # echo 123 > buffer_size_kb     // current:123,  spare:1408
  # echo 1 > snapshot             // current:1408, spare:123
  # grep bytes per_cpu/cpu0/stats
  bytes: 1443700
  # cat buffer_size_kb
  123                             // != current:1408

And also, a similar per-cpu case hits the following WARNING:

Reproducer:

  # echo 1 > per_cpu/cpu0/snapshot
  # echo 123 > buffer_size_kb
  # echo 1 > per_cpu/cpu0/snapshot

WARNING:

  WARNING: CPU: 0 PID: 1946 at kernel/trace/trace.c:1607 update_max_tr_single.part.0+0x2b8/0x380
  Modules linked in:
  CPU: 0 PID: 1946 Comm: bash Not tainted 5.2.0-rc6 #20
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014
  RIP: 0010:update_max_tr_single.part.0+0x2b8/0x380
  Code: ff e8 dc da f9 ff 0f 0b e9 88 fe ff ff e8 d0 da f9 ff 44 89 ee bf f5 ff ff ff e8 33 dc f9 ff 41 83 fd f5 74 96 e8 b8 da f9 ff <0f> 0b eb 8d e8 af da f9 ff 0f 0b e9 bf fd ff ff e8 a3 da f9 ff 48
  RSP: 0018:ffff888063e4fca0 EFLAGS: 00010093
  RAX: ffff888066214380 RBX: ffffffff99850fe0 RCX: ffffffff964298a8
  RDX: 0000000000000000 RSI: 00000000fffffff5 RDI: 0000000000000005
  RBP: 1ffff1100c7c9f96 R08: ffff888066214380 R09: ffffed100c7c9f9b
  R10: ffffed100c7c9f9a R11: 0000000000000003 R12: 0000000000000000
  R13: 00000000ffffffea R14: ffff888066214380 R15: ffffffff99851060
  FS:  00007f9f8173c700(0000) GS:ffff88806d000000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000714dc0 CR3: 0000000066fa6000 CR4: 00000000000006f0
  Call Trace:
   ? trace_array_printk_buf+0x140/0x140
   ? __mutex_lock_slowpath+0x10/0x10
   tracing_snapshot_write+0x4c8/0x7f0
   ? trace_printk_init_buffers+0x60/0x60
   ? selinux_file_permission+0x3b/0x540
   ? tracer_preempt_off+0x38/0x506
   ? trace_printk_init_buffers+0x60/0x60
   __vfs_write+0x81/0x100
   vfs_write+0x1e1/0x560
   ksys_write+0x126/0x250
   ? __ia32_sys_read+0xb0/0xb0
   ? do_syscall_64+0x1f/0x390
   do_syscall_64+0xc1/0x390
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

This patch adds resize_buffer_duplicate_size() to check if there is a
difference between current/spare buffer sizes and resize a spare buffer
if necessary.

Link: http://lkml.kernel.org/r/20190625012910.13109-1-devel@etsukata.com

Cc: stable@vger.kernel.org
Fixes: ad909e21bbe69 ("tracing: Add internal tracing_snapshot() functions")
Signed-off-by: Eiichi Tsukata <devel@etsukata.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-06-28 14:58:52 -04:00
..
bpf
bpf: fix undefined behavior in narrow load handling
2019-05-13 02:05:50 +02:00
cgroup
kernel/sched/psi.c: expose pressure metrics on root cgroup
2019-05-14 19:52:48 -07:00
configs
kvm_config: add CONFIG_VIRTIO_MENU
2018-10-24 20:55:56 -04:00
debug
kdb: Fix bound check compiler warning
2019-05-14 13:44:24 +01:00
dma
DMA mapping updates for 5.2
2019-05-09 08:40:55 -07:00
events
mm/mmu_notifier: use correct mmu_notifier events for each invalidation
2019-05-14 09:47:49 -07:00
gcov
gcov: clang support
2019-05-14 19:52:51 -07:00
irq
Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2019-05-19 10:58:45 -07:00
livepatch
module: Fix livepatch/ftrace module text permissions race
2019-06-14 17:01:50 -04:00
locking
locking/rwsem: Prevent decrement of reader count before increment
2019-05-07 08:46:46 +02:00
power
Power management updates for 5.2-rc1
2019-05-06 19:40:31 -07:00
printk
panic: add an option to replay all the printk message in buffer
2019-05-18 15:52:26 -07:00
rcu
The major changes in this tracing update includes:
2019-05-15 16:05:47 -07:00
sched
kernel/sched/psi.c: expose pressure metrics on root cgroup
2019-05-14 19:52:48 -07:00
time
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2019-05-16 11:00:20 -07:00
trace
tracing/snapshot: Resize spare buffer if size changed
2019-06-28 14:58:52 -04:00
.gitignore
Provide in-kernel headers to make extending kernel easier
2019-04-29 16:48:03 +02:00
acct.c
acct_on(): don't mess with freeze protection
2019-04-04 21:04:13 -04:00
async.c
treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively
2019-04-09 14:19:06 +02:00
audit_fsnotify.c
audit_compare_dname_path(): switch to const struct qstr *
2019-04-28 20:33:43 -04:00
audit_tree.c
fsnotify: switch send_to_group() and ->handle_event to const struct qstr *
2019-04-26 13:51:03 -04:00
audit_watch.c
audit_compare_dname_path(): switch to const struct qstr *
2019-04-28 20:33:43 -04:00
audit.c
audit: connect LOGIN record to its syscall record
2019-03-20 20:57:48 -04:00
audit.h
audit_compare_dname_path(): switch to const struct qstr *
2019-04-28 20:33:43 -04:00
auditfilter.c
Merge branch 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2019-05-07 20:03:32 -07:00
auditsc.c
Merge branch 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2019-05-07 20:03:32 -07:00
backtracetest.c
backtrace-test: Simplify stack trace handling
2019-04-29 12:37:47 +02:00
bounds.c
kbuild: fix kernel/bounds.c 'W=1' warning
2018-10-31 08:54:14 -07:00
capability.c
LSM: add SafeSetID module that gates setid calls
2019-01-25 11:22:43 -08:00
compat.c
kernel/compat.c: mark expected switch fall-throughs
2019-05-15 08:16:14 -07:00
configs.c
kernel/configs: use .incbin directive to embed config_data.gz
2019-03-07 18:32:02 -08:00
context_tracking.c
…
cpu_pm.c
…
cpu.c
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2019-05-06 14:50:46 -07:00
crash_core.c
kexec: export PG_offline to VMCOREINFO
2019-03-05 21:07:14 -08:00
crash_dump.c
…
cred.c
SELinux: Remove cred security blob poisoning
2019-01-08 13:18:44 -08:00
delayacct.c
delayacct: track delays from thrashing cache pages
2018-10-26 16:26:32 -07:00
dma.c
…
elfcore.c
…
exec_domain.c
…
exit.c
mm: change mm_update_next_owner() to update mm->owner with WRITE_ONCE
2019-05-14 19:52:47 -07:00
extable.c
…
fail_function.c
treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively
2019-04-09 14:19:06 +02:00
fork.c
kernel/latencytop.c: rename clear_all_latency_tracing to clear_tsk_latency_tracing
2019-05-14 19:52:49 -07:00
freezer.c
…
futex.c
mm/gup: change GUP fast to use flags rather than a write 'bool'
2019-05-14 09:47:46 -07:00
gen_ikh_data.sh
Provide in-kernel headers to make extending kernel easier
2019-04-29 16:48:03 +02:00
groups.c
…
hung_task.c
kernel/hung_task.c: Use continuously blocked time when reporting.
2019-03-07 18:31:59 -08:00
iomem.c
mm/resource: Use resource_overlaps() to simplify region_intersects()
2019-04-19 12:59:36 +02:00
irq_work.c
irq_work: Do not raise an IPI when queueing work on the local CPU
2019-04-18 14:07:52 +02:00
jump_label.c
locking/static_key: Don't take sleeping locks in __static_key_slow_dec_deferred()
2019-04-29 08:29:21 +02:00
kallsyms.c
bpf: Add module name [bpf] to ksymbols for bpf programs
2019-01-21 17:38:56 -03:00
kcmp.c
…
Kconfig.freezer
…
Kconfig.hz
…
Kconfig.locks
Remove Mysterious Macro Intended to Obscure Weird Behaviours (mmiowb())
2019-05-06 16:57:52 -07:00
Kconfig.preempt
kconfig: warn no new line at end of file
2018-12-15 17:44:35 +09:00
kcov.c
kcov: convert kcov.refcount to refcount_t
2019-03-07 18:32:02 -08:00
kexec_core.c
power/suspend: Add function to disable secondaries for suspend
2019-05-03 19:42:41 +02:00
kexec_file.c
mm: memblock: make keeping memblock memory opt-in rather than opt-out
2019-05-14 09:47:50 -07:00
kexec_internal.h
…
kexec.c
…
kheaders.c
Provide in-kernel headers to make extending kernel easier
2019-04-29 16:48:03 +02:00
kmod.c
…
kprobes.c
kprobes: Fix error check when reusing optimized probes
2019-04-16 09:38:16 +02:00
ksysfs.c
…
kthread.c
include/: refactor headers to allow kthread.h inclusion in psi_types.h
2019-05-14 19:52:48 -07:00
latencytop.c
kernel/latencytop.c: rename clear_all_latency_tracing to clear_tsk_latency_tracing
2019-05-14 19:52:49 -07:00
Makefile
kernel/Makefile: don't assume that kernel/gen_ikh_data.sh is executable
2019-05-14 19:52:47 -07:00
memremap.c
kernel/memremap.c: remove the unused device_private_entry_fault() export
2019-05-14 09:47:51 -07:00
module_signing.c
modsign: use all trusted keys to verify module signature
2018-11-07 14:41:41 +01:00
module-internal.h
kallsyms: store type information in its own array
2019-03-28 15:00:37 +01:00
module.c
Modules updates for v5.2
2019-05-14 10:55:54 -07:00
notifier.c
kernel/notifier.c: double register detection
2019-05-14 19:52:49 -07:00
nsproxy.c
…
padata.c
padata: Replace padata_attr_type default_attrs field with groups
2019-04-25 22:06:11 +02:00
panic.c
panic: add an option to replay all the printk message in buffer
2019-05-18 15:52:26 -07:00
params.c
…
pid_namespace.c
signal: Use group_send_sig_info to kill all processes in a pid namespace
2018-09-16 16:08:25 +02:00
pid.c
kernel/pid.c: remove unneeded hash header file
2019-05-14 19:52:51 -07:00
profile.c
mm: remove include/linux/bootmem.h
2018-10-31 08:54:16 -07:00
ptrace.c
ptrace: take into account saved_sigmask in PTRACE{GET,SET}SIGMASK
2019-03-29 10:01:37 -07:00
range.c
…
reboot.c
panic/reboot: allow specifying reboot_mode for panic only
2019-05-14 19:52:51 -07:00
relay.c
Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2019-03-12 13:27:20 -07:00
resource.c
mm/resource: Use resource_overlaps() to simplify region_intersects()
2019-04-19 12:59:36 +02:00
rseq.c
rseq: Remove superfluous rseq_len from task_struct
2019-04-19 12:39:32 +02:00
seccomp.c
audit/stable-5.2 PR 20190507
2019-05-07 19:06:04 -07:00
signal.c
signal: unconditionally leave the frozen state in ptrace_stop()
2019-05-16 10:43:58 -07:00
smp.c
cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM
2019-01-30 19:27:00 +01:00
smpboot.c
…
smpboot.h
…
softirq.c
softirq: Remove tasklet_hrtimer
2019-03-22 14:36:02 +01:00
stackleak.c
stackleak: Mark stackleak_track_stack() as notrace
2018-12-05 19:31:44 -08:00
stacktrace.c
stacktrace: Provide common infrastructure
2019-04-29 12:37:57 +02:00
stop_machine.c
treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively
2019-04-09 14:19:06 +02:00
sys_ni.c
signal: support CLONE_PIDFD with pidfd_send_signal
2019-05-07 14:31:03 +02:00
sys.c
kernel/sys.c: prctl: fix false positive in validate_prctl_map()
2019-05-14 09:47:44 -07:00
sysctl_binary.c
kernel/sysctl: add panic_print into sysctl
2019-01-04 13:13:47 -08:00
sysctl.c
kernel/sysctl.c: fix proc_do_large_bitmap for large input buffers
2019-05-14 19:52:51 -07:00
task_work.c
…
taskstats.c
genetlink: optionally validate strictly/dumps
2019-04-27 17:07:22 -04:00
test_kprobes.c
…
torture.c
torture: Don't try to offline the last CPU
2019-03-26 14:42:53 -07:00
tracepoint.c
tracing: Replace synchronize_sched() and call_rcu_sched()
2018-11-27 09:21:41 -08:00
tsacct.c
…
ucount.c
…
uid16.c
…
uid16.h
…
umh.c
umh: add exit routine for UMH process
2019-01-11 18:05:40 -08:00
up.c
smp,cpumask: introduce on_each_cpu_cond_mask
2018-10-09 16:51:11 +02:00
user_namespace.c
userns: also map extents in the reverse map to kernel IDs
2018-11-07 23:51:16 -06:00
user-return-notifier.c
…
user.c
kernel/user.c: clean up some leftover code
2019-05-14 19:52:49 -07:00
utsname_sysctl.c
…
utsname.c
…
watchdog_hld.c
kernel/watchdog_hld.c: hard lockup message should end with a newline
2019-04-19 09:46:05 -07:00
watchdog.c
watchdog: Fix typo in comment
2019-04-18 14:05:51 +02:00
workqueue_internal.h
sched/core, workqueues: Distangle worker accounting from rq lock
2019-04-16 16:55:15 +02:00
workqueue.c
Merge branch 'for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2019-05-09 13:48:52 -07:00