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Mukesh Ojha 9674390ac5 ring-buffer: Handle race between rb_move_tail and rb_check_pages 
commit 8843e06f67 upstream.

It seems a data race between ring_buffer writing and integrity check.
That is, RB_FLAG of head_page is been updating, while at same time
RB_FLAG was cleared when doing integrity check rb_check_pages():

  rb_check_pages()            rb_handle_head_page():
  --------                    --------
  rb_head_page_deactivate()
                              rb_head_page_set_normal()
  rb_head_page_activate()

We do intergrity test of the list to check if the list is corrupted and
it is still worth doing it. So, let's refactor rb_check_pages() such that
we no longer clear and set flag during the list sanity checking.

[1] and [2] are the test to reproduce and the crash report respectively.

1:
``` read_trace.sh
  while true;
  do
    # the "trace" file is closed after read
    head -1 /sys/kernel/tracing/trace > /dev/null
  done
```
``` repro.sh
  sysctl -w kernel.panic_on_warn=1
  # function tracer will writing enough data into ring_buffer
  echo function > /sys/kernel/tracing/current_tracer
  ./read_trace.sh &
  ./read_trace.sh &
  ./read_trace.sh &
  ./read_trace.sh &
  ./read_trace.sh &
  ./read_trace.sh &
  ./read_trace.sh &
  ./read_trace.sh &
```

2:
------------[ cut here ]------------
WARNING: CPU: 9 PID: 62 at kernel/trace/ring_buffer.c:2653
rb_move_tail+0x450/0x470
Modules linked in:
CPU: 9 PID: 62 Comm: ksoftirqd/9 Tainted: G        W          6.2.0-rc6+
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014
RIP: 0010:rb_move_tail+0x450/0x470
Code: ff ff 4c 89 c8 f0 4d 0f b1 02 48 89 c2 48 83 e2 fc 49 39 d0 75 24
83 e0 03 83 f8 02 0f 84 e1 fb ff ff 48 8b 57 10 f0 ff 42 08 <0f> 0b 83
f8 02 0f 84 ce fb ff ff e9 db
RSP: 0018:ffffb5564089bd00 EFLAGS: 00000203
RAX: 0000000000000000 RBX: ffff9db385a2bf81 RCX: ffffb5564089bd18
RDX: ffff9db281110100 RSI: 0000000000000fe4 RDI: ffff9db380145400
RBP: ffff9db385a2bf80 R08: ffff9db385a2bfc0 R09: ffff9db385a2bfc2
R10: ffff9db385a6c000 R11: ffff9db385a2bf80 R12: 0000000000000000
R13: 00000000000003e8 R14: ffff9db281110100 R15: ffffffffbb006108
FS:  0000000000000000(0000) GS:ffff9db3bdcc0000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005602323024c8 CR3: 0000000022e0c000 CR4: 00000000000006e0
Call Trace:
 <TASK>
 ring_buffer_lock_reserve+0x136/0x360
 ? __do_softirq+0x287/0x2df
 ? __pfx_rcu_softirq_qs+0x10/0x10
 trace_function+0x21/0x110
 ? __pfx_rcu_softirq_qs+0x10/0x10
 ? __do_softirq+0x287/0x2df
 function_trace_call+0xf6/0x120
 0xffffffffc038f097
 ? rcu_softirq_qs+0x5/0x140
 rcu_softirq_qs+0x5/0x140
 __do_softirq+0x287/0x2df
 run_ksoftirqd+0x2a/0x30
 smpboot_thread_fn+0x188/0x220
 ? __pfx_smpboot_thread_fn+0x10/0x10
 kthread+0xe7/0x110
 ? __pfx_kthread+0x10/0x10
 ret_from_fork+0x2c/0x50
 </TASK>
---[ end trace 0000000000000000 ]---

[ crash report and test reproducer credit goes to Zheng Yejian]

Link: https://lore.kernel.org/linux-trace-kernel/1676376403-16462-1-git-send-email-quic_mojha@quicinc.com

Cc: <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 1039221cc2 ("ring-buffer: Do not disable recording when there is an iterator")
Reported-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2023-03-10 09:34:27 +01:00
arch mips: fix syscall_get_nr 2023-03-10 09:34:26 +01:00
block block: be a bit more careful in checking for NULL bdev while polling 2023-03-10 09:34:02 +01:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: rsa-pkcs1pad - Use akcipher_request_complete 2023-03-10 09:33:03 +01:00
Documentation mm: memcontrol: deprecate charge moving 2023-03-10 09:34:26 +01:00
drivers remoteproc/mtk_scp: Move clk ops outside send_lock 2023-03-10 09:34:26 +01:00
fs ceph: update the time stamps and try to drop the suid/sgid 2023-03-10 09:34:25 +01:00
include mm/hwpoison: convert TTU_IGNORE_HWPOISON to TTU_HWPOISON 2023-03-10 09:34:25 +01:00
init gcc: disable -Warray-bounds for gcc-11 too 2023-01-14 10:33:43 +01:00
io_uring io_uring: mark task TASK_RUNNING before handling resume/task work 2023-03-10 09:34:07 +01:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel ring-buffer: Handle race between rb_move_tail and rb_check_pages 2023-03-10 09:34:27 +01:00
lib cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG 2023-03-10 09:33:47 +01:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm memory tier: release the new_memtier in find_create_memory_tier() 2023-03-10 09:34:27 +01:00
net wifi: cfg80211: Set SSID if it is not already set 2023-03-10 09:34:22 +01:00
rust rust: print: avoid evaluating arguments in pr_* macros in unsafe blocks 2023-02-06 08:06:34 +01:00
samples ftrace: Export ftrace_free_filter() to modules 2023-02-01 08:34:37 +01:00
scripts gcc-plugins: drop -std=gnu++11 to fix GCC 13 build 2023-03-10 09:33:51 +01:00
security ima: Align ima_file_mmap() parameters with mmap_file LSM hook 2023-03-10 09:34:15 +01:00
sound ALSA: hda/realtek: Add quirk for HP EliteDesk 800 G6 Tower PC 2023-03-10 09:34:20 +01:00
tools ktest.pl: Add RUN_TIMEOUT option with default unlimited 2023-03-10 09:34:27 +01:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Register /dev/kvm as the _very_ last thing during initialization 2023-03-10 09:34:11 +01:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS audit: update the mailing list in MAINTAINERS 2023-02-25 11:25:42 +01:00
Makefile Linux 6.1.15 2023-03-03 11:52:25 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.