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Zheng Yejian 299e0033f1 tracing: Fix cpu buffers unavailable due to 'record_disabled' missed
[ Upstream commit b71645d6af ]

Trace ring buffer can no longer record anything after executing
following commands at the shell prompt:

  # cd /sys/kernel/tracing
  # cat tracing_cpumask
  fff
  # echo 0 > tracing_cpumask
  # echo 1 > snapshot
  # echo fff > tracing_cpumask
  # echo 1 > tracing_on
  # echo "hello world" > trace_marker
  -bash: echo: write error: Bad file descriptor

The root cause is that:
  1. After `echo 0 > tracing_cpumask`, 'record_disabled' of cpu buffers
     in 'tr->array_buffer.buffer' became 1 (see tracing_set_cpumask());
  2. After `echo 1 > snapshot`, 'tr->array_buffer.buffer' is swapped
     with 'tr->max_buffer.buffer', then the 'record_disabled' became 0
     (see update_max_tr());
  3. After `echo fff > tracing_cpumask`, the 'record_disabled' become -1;
Then array_buffer and max_buffer are both unavailable due to value of
'record_disabled' is not 0.

To fix it, enable or disable both array_buffer and max_buffer at the same
time in tracing_set_cpumask().

Link: https://lkml.kernel.org/r/20230805033816.3284594-2-zhengyejian1@huawei.com

Cc: <mhiramat@kernel.org>
Cc: <vnagarnaik@google.com>
Cc: <shuah@kernel.org>
Fixes: 71babb2705 ("tracing: change CPU ring buffer state from tracing_cpumask")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-30 14:52:28 +02:00
arch arm64/ptrace: Ensure that the task sees ZT writes on first use 2023-08-23 17:32:53 +02:00
block blk-crypto: dynamically allocate fallback profile 2023-08-23 17:32:53 +02:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto crypto: jitter - correct health test during initialization 2023-07-19 16:36:19 +02:00
Documentation dt-bindings: pinctrl: qcom,sa8775p-tlmm: add gpio function constant 2023-08-23 17:32:53 +02:00
drivers wifi: iwlwifi: mvm: add dependency for PTP clock 2023-08-30 14:52:28 +02:00
fs jbd2: fix a race when checking checkpoint buffer busy 2023-08-30 14:52:28 +02:00
include jbd2: fix a race when checking checkpoint buffer busy 2023-08-30 14:52:28 +02:00
init init, x86: Move mem_encrypt_init() into arch_cpu_finalize_init() 2023-08-08 20:04:49 +02:00
io_uring io_uring: correct check for O_TMPFILE 2023-08-16 18:32:19 +02:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel tracing: Fix cpu buffers unavailable due to 'record_disabled' missed 2023-08-30 14:52:28 +02:00
lib debugobjects: Recheck debug_objects_enabled before reporting 2023-08-11 12:14:25 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: memory-failure: avoid false hwpoison page mapped error info 2023-08-16 18:32:20 +02:00
net can: raw: fix lockdep issue in raw_release() 2023-08-30 14:52:28 +02:00
rust rust: macros: vtable: fix HAS_* redefinition (gen_const_name) 2023-08-23 17:32:36 +02:00
samples samples: ftrace: Save required argument registers in sample trampolines 2023-07-23 13:54:09 +02:00
scripts kbuild: rust: avoid creating temporary files 2023-07-27 08:57:06 +02:00
security security: keys: Modify mismatched function name 2023-07-27 08:56:59 +02:00
sound ASoC: SOF: intel: hda: Clean up link DMA for IPC3 during stop 2023-08-23 17:32:56 +02:00
tools Revert "perf report: Append inlines to non-DWARF callchains" 2023-08-23 17:32:56 +02:00
usr initramfs: Check negative timestamp to prevent broken cpio archive 2023-04-16 17:37:01 +09:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-08-03 10:26:01 +02:00
.clang-format cxl for v6.4 2023-04-30 11:51:51 -07:00
.cocciconfig
.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 *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore linux-kselftest-kunit-6.4-rc1 2023-04-24 12:31:32 -07:00
.mailmap mailmap: add entries for Ben Dooks 2023-06-19 13:19:35 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS MAINTAINERS: sctp: move Neil to CREDITS 2023-05-12 08:51:32 +01:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig
MAINTAINERS Networking fixes for 6.4-rc8, including fixes from ipsec, bpf, 2023-06-22 17:59:51 -07:00
Makefile Linux 6.4.12 2023-08-23 17:32:56 +02:00
README

Linux kernel
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There are several guides for kernel developers and users. These guides can
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There are various text files in the Documentation/ subdirectory,
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