twx-linux/kernel
Zheng Yejian 6455b6163d ring-buffer: Fix race while reader and writer are on the same page
When user reads file 'trace_pipe', kernel keeps printing following logs
that warn at "cpu_buffer->reader_page->read > rb_page_size(reader)" in
rb_get_reader_page(). It just looks like there's an infinite loop in
tracing_read_pipe(). This problem occurs several times on arm64 platform
when testing v5.10 and below.

  Call trace:
   rb_get_reader_page+0x248/0x1300
   rb_buffer_peek+0x34/0x160
   ring_buffer_peek+0xbc/0x224
   peek_next_entry+0x98/0xbc
   __find_next_entry+0xc4/0x1c0
   trace_find_next_entry_inc+0x30/0x94
   tracing_read_pipe+0x198/0x304
   vfs_read+0xb4/0x1e0
   ksys_read+0x74/0x100
   __arm64_sys_read+0x24/0x30
   el0_svc_common.constprop.0+0x7c/0x1bc
   do_el0_svc+0x2c/0x94
   el0_svc+0x20/0x30
   el0_sync_handler+0xb0/0xb4
   el0_sync+0x160/0x180

Then I dump the vmcore and look into the problematic per_cpu ring_buffer,
I found that tail_page/commit_page/reader_page are on the same page while
reader_page->read is obviously abnormal:
  tail_page == commit_page == reader_page == {
    .write = 0x100d20,
    .read = 0x8f9f4805,  // Far greater than 0xd20, obviously abnormal!!!
    .entries = 0x10004c,
    .real_end = 0x0,
    .page = {
      .time_stamp = 0x857257416af0,
      .commit = 0xd20,  // This page hasn't been full filled.
      // .data[0...0xd20] seems normal.
    }
 }

The root cause is most likely the race that reader and writer are on the
same page while reader saw an event that not fully committed by writer.

To fix this, add memory barriers to make sure the reader can see the
content of what is committed. Since commit a0fcaaed0c46 ("ring-buffer: Fix
race between reset page and reading page") has added the read barrier in
rb_get_reader_page(), here we just need to add the write barrier.

Link: https://lore.kernel.org/linux-trace-kernel/20230325021247.2923907-1-zhengyejian1@huawei.com

Cc: stable@vger.kernel.org
Fixes: 77ae365eca89 ("ring-buffer: make lockless")
Suggested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-04-03 11:51:38 -04:00
..
bpf bpf: Adjust insufficient default bpf_jit_limit 2023-03-21 12:43:05 -07:00
cgroup Networking changes for 6.3. 2023-02-21 18:24:12 -08:00
configs mm, slob: rename CONFIG_SLOB to CONFIG_SLOB_DEPRECATED 2022-12-01 00:09:20 +01:00
debug kdb: use srcu console list iterator 2022-12-02 11:25:00 +01:00
dma swiotlb: fix slot alignment checks 2023-03-22 09:03:17 +01:00
entry entry/rcu: Check TIF_RESCHED _after_ delayed RCU wake-up 2023-03-21 15:13:15 +01:00
events perf: Fix check before add_event_to_groups() in perf_group_detach() 2023-03-15 21:49:47 +01:00
futex - Prevent the leaking of a debug timer in futex_waitv() 2023-01-01 11:15:05 -08:00
gcov gcov: add support for checksum field 2022-12-21 14:31:52 -08:00
irq A set of updates for the interrupt susbsystem: 2023-03-05 11:19:16 -08:00
kcsan kcsan: avoid passing -g for test 2023-03-23 17:18:35 -07:00
livepatch Livepatching changes for 6.3 2023-02-23 14:00:10 -08:00
locking RCU pull request for v6.3 2023-02-21 10:45:51 -08:00
module modules-6.3-rc1 2023-02-23 14:05:08 -08:00
power Merge branches 'powercap', 'pm-domains', 'pm-em' and 'pm-opp' 2023-02-15 20:06:26 +01:00
printk printk changes for 6.3 2023-02-23 13:49:45 -08:00
rcu Merge branch 'stall.2023.01.09a' into HEAD 2023-02-02 16:40:07 -08:00
sched sched/fair: Sanitize vruntime of entity being migrated 2023-03-21 14:43:04 +01:00
time Updates for timekeeping, timers and clockevent/source drivers: 2023-02-21 09:45:13 -08:00
trace ring-buffer: Fix race while reader and writer are on the same page 2023-04-03 11:51:38 -04:00
.gitignore
acct.c acct: fix potential integer overflow in encode_comp_t() 2022-11-30 16:13:18 -08:00
async.c
audit_fsnotify.c audit: fix potential double free on error path from fsnotify_add_inode_mark 2022-08-22 18:50:06 -04:00
audit_tree.c
audit_watch.c audit_init_parent(): constify path 2022-09-01 17:39:30 -04:00
audit.c audit: use time_after to compare time 2022-08-29 19:47:03 -04:00
audit.h audit: remove selinux_audit_rule_update() declaration 2022-09-07 11:30:15 -04:00
auditfilter.c
auditsc.c capability: just use a 'u64' instead of a 'u32[2]' array 2023-03-01 10:01:22 -08:00
backtracetest.c
bounds.c mm: multi-gen LRU: minimal implementation 2022-09-26 19:46:09 -07:00
capability.c capability: just use a 'u64' instead of a 'u32[2]' array 2023-03-01 10:01:22 -08:00
cfi.c cfi: Switch to -fsanitize=kcfi 2022-09-26 10:13:13 -07:00
compat.c sched_getaffinity: don't assume 'cpumask_size()' is fully initialized 2023-03-14 19:32:38 -07:00
configs.c
context_tracking.c context_tracking: Fix noinstr vs KASAN 2023-01-13 11:48:18 +01:00
cpu_pm.c cpuidle, cpu_pm: Remove RCU fiddling from cpu_pm_{enter,exit}() 2023-01-13 11:48:15 +01:00
cpu.c cpu/hotplug: Do not bail-out in DYING/STARTING sections 2022-12-02 12:43:02 +01:00
crash_core.c mm: remove 'First tail page' members from struct page 2023-02-02 22:32:59 -08:00
crash_dump.c
cred.c cred: Do not default to init_cred in prepare_kernel_cred() 2022-11-01 10:04:52 -07:00
delayacct.c delayacct: support re-entrance detection of thrashing accounting 2022-09-26 19:46:07 -07:00
dma.c
exec_domain.c
exit.c arm64 updates for 6.3: 2023-02-21 15:27:48 -08:00
extable.c context_tracking: Take NMI eqs entrypoints over RCU 2022-07-05 13:32:59 -07:00
fail_function.c kernel/fail_function: fix memory leak with using debugfs_lookup() 2023-02-08 13:36:22 +01:00
fork.c Fixes for 6.3-rc3: 2023-03-25 12:57:34 -07:00
freezer.c freezer,sched: Rewrite core freezer logic 2022-09-07 21:53:50 +02:00
gen_kheaders.sh kheaders: use standard naming for the temporary directory 2023-01-22 23:43:34 +09:00
groups.c security: Add LSM hook to setgroups() syscall 2022-07-15 18:21:49 +00:00
hung_task.c hung_task: print message when hung_task_warnings gets down to zero. 2023-02-09 17:03:20 -08:00
iomem.c
irq_work.c
jump_label.c jump_label: Prevent key->enabled int overflow 2022-12-01 15:53:05 -08:00
kallsyms_internal.h kallsyms: Reduce the memory occupied by kallsyms_seqs_of_names[] 2022-11-12 18:47:36 -08:00
kallsyms_selftest.c kallsyms: Fix scheduling with interrupts disabled in self-test 2023-01-13 15:09:08 -08:00
kallsyms_selftest.h kallsyms: Add self-test facility 2022-11-15 00:42:02 -08:00
kallsyms.c kallsyms: Add self-test facility 2022-11-15 00:42:02 -08:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c mm: replace vma->vm_flags direct modifications with modifier calls 2023-02-09 16:51:39 -08:00
kexec_core.c There is no particular theme here - mainly quick hits all over the tree. 2023-02-23 17:55:40 -08:00
kexec_elf.c
kexec_file.c kexec: introduce sysctl parameters kexec_load_limit_* 2023-02-02 22:50:05 -08:00
kexec_internal.h panic, kexec: make __crash_kexec() NMI safe 2022-09-11 21:55:06 -07:00
kexec.c kexec: introduce sysctl parameters kexec_load_limit_* 2023-02-02 22:50:05 -08:00
kheaders.c
kmod.c
kprobes.c x86/kprobes: Fix arch_check_optimized_kprobe check within optimized_kprobe range 2023-02-21 08:49:16 +09:00
ksysfs.c kernels/ksysfs.c: export kernel address bits 2023-01-20 14:30:45 +01:00
kthread.c kthread_worker: check all delayed works when destroy kthread worker 2023-02-02 22:50:02 -08:00
latencytop.c latencytop: use the last element of latency_record of system 2022-09-11 21:55:12 -07:00
Makefile kernel hardening fixes for v6.2-rc1 2022-12-23 12:00:24 -08:00
module_signature.c
notifier.c kernel/notifier: Remove CONFIG_SRCU 2023-02-02 16:26:06 -08:00
nsproxy.c fs/exec: switch timens when a task gets a new mm 2022-10-25 15:15:52 -07:00
padata.c Kbuild updates for v6.2 2022-12-19 12:33:32 -06:00
panic.c panic: fix the panic_print NMI backtrace setting 2023-03-02 21:54:23 -08:00
params.c kernel/params.c: Use kstrtobool() instead of strtobool() 2023-01-25 14:07:21 -08:00
pid_namespace.c - Daniel Verkamp has contributed a memfd series ("mm/memfd: add 2023-02-23 17:09:35 -08:00
pid_sysctl.h mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC 2023-01-18 17:12:37 -08:00
pid.c gfs2: Add glockfd debugfs file 2022-06-29 13:07:16 +02:00
profile.c kernel/profile.c: simplify duplicated code in profile_setup() 2022-09-11 21:55:12 -07:00
ptrace.c rseq: Introduce extensible rseq ABI 2022-12-27 12:52:10 +01:00
range.c
reboot.c kernel/reboot: Add SYS_OFF_MODE_RESTART_PREPARE mode 2022-10-04 15:59:36 +02:00
regset.c
relay.c mm: replace vma->vm_flags direct modifications with modifier calls 2023-02-09 16:51:39 -08:00
resource_kunit.c
resource.c dax/kmem: Fix leak of memory-hotplug resources 2023-02-17 14:58:01 -08:00
rseq.c rseq: Extend struct rseq with per-memory-map concurrency ID 2022-12-27 12:52:12 +01:00
scftorture.c
scs.c scs: add support for dynamic shadow call stacks 2022-11-09 18:06:35 +00:00
seccomp.c seccomp: fix kernel-doc function name warning 2023-01-13 17:01:06 -08:00
signal.c sched: Introduce per-memory-map concurrency ID 2022-12-27 12:52:11 +01:00
smp.c bitmap patches for v6.1-rc1 2022-10-10 12:49:34 -07:00
smpboot.c smpboot: use atomic_try_cmpxchg in cpu_wait_death and cpu_report_death 2022-09-11 21:55:10 -07:00
smpboot.h
softirq.c context_tracking: Take IRQ eqs entrypoints over RCU 2022-07-05 13:32:59 -07:00
stackleak.c
stacktrace.c
static_call_inline.c static_call: Add call depth tracking support 2022-10-17 16:41:16 +02:00
static_call.c
stop_machine.c
sys_ni.c kernel/sys_ni: add compat entry for fadvise64_64 2022-08-20 15:17:45 -07:00
sys.c - Daniel Verkamp has contributed a memfd series ("mm/memfd: add 2023-02-23 17:09:35 -08:00
sysctl-test.c kernel/sysctl-test: use SYSCTL_{ZERO/ONE_HUNDRED} instead of i_{zero/one_hundred} 2022-09-08 16:56:45 -07:00
sysctl.c sysctl: fix proc_dobool() usability 2023-02-21 13:34:07 -08:00
task_work.c task_work: use try_cmpxchg in task_work_add, task_work_cancel_match and task_work_run 2022-09-11 21:55:10 -07:00
taskstats.c genetlink: start to validate reserved header bytes 2022-08-29 12:47:15 +01:00
torture.c torture: Fix hang during kthread shutdown phase 2023-01-05 12:10:35 -08:00
tracepoint.c tracepoint: Allow livepatch module add trace event 2023-02-18 14:34:36 -05:00
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c umh: simplify the capability pointer logic 2023-03-03 16:18:19 -08:00
up.c
user_namespace.c userns: fix a struct's kernel-doc notation 2023-02-02 22:50:04 -08:00
user-return-notifier.c
user.c kernel/user: Allow user_struct::locked_vm to be usable for iommufd 2022-11-30 20:16:49 -04:00
usermode_driver.c
utsname_sysctl.c kernel/utsname_sysctl.c: Fix hostname polling 2022-10-23 12:01:01 -07:00
utsname.c
watch_queue.c watch_queue: fix IOC_WATCH_QUEUE_SET_SIZE alloc error paths 2023-03-08 11:44:45 +01:00
watchdog_hld.c Revert "printk: add functions to prefer direct printing" 2022-06-23 18:41:40 +02:00
watchdog.c powerpc updates for 6.0 2022-08-06 16:38:17 -07:00
workqueue_internal.h
workqueue.c workqueue: Fold rebind_worker() within rebind_workers() 2023-01-13 07:50:40 -10:00