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Tengda Wu c85efe6e13 tracing: Fix use-after-free in print_graph_function_flags during tracer switching
commit 7f81f27b10 upstream.

Kairui reported a UAF issue in print_graph_function_flags() during
ftrace stress testing [1]. This issue can be reproduced if puting a
'mdelay(10)' after 'mutex_unlock(&trace_types_lock)' in s_start(),
and executing the following script:

  $ echo function_graph > current_tracer
  $ cat trace > /dev/null &
  $ sleep 5  # Ensure the 'cat' reaches the 'mdelay(10)' point
  $ echo timerlat > current_tracer

The root cause lies in the two calls to print_graph_function_flags
within print_trace_line during each s_show():

  * One through 'iter->trace->print_line()';
  * Another through 'event->funcs->trace()', which is hidden in
    print_trace_fmt() before print_trace_line returns.

Tracer switching only updates the former, while the latter continues
to use the print_line function of the old tracer, which in the script
above is print_graph_function_flags.

Moreover, when switching from the 'function_graph' tracer to the
'timerlat' tracer, s_start only calls graph_trace_close of the
'function_graph' tracer to free 'iter->private', but does not set
it to NULL. This provides an opportunity for 'event->funcs->trace()'
to use an invalid 'iter->private'.

To fix this issue, set 'iter->private' to NULL immediately after
freeing it in graph_trace_close(), ensuring that an invalid pointer
is not passed to other tracers. Additionally, clean up the unnecessary
'iter->private = NULL' during each 'cat trace' when using wakeup and
irqsoff tracers.

 [1] https://lore.kernel.org/all/20231112150030.84609-1-ryncsn@gmail.com/

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Zheng Yejian <zhengyejian1@huawei.com>
Link: https://lore.kernel.org/20250320122137.23635-1-wutengda@huaweicloud.com
Fixes: eecb91b9f9 ("tracing: Fix memleak due to race between current_tracer and trace")
Closes: https://lore.kernel.org/all/CAMgjq7BW79KDSCyp+tZHjShSzHsScSiJxn5ffskp-QzVM06fxw@mail.gmail.com/
Reported-by: Kairui Song <kasong@tencent.com>
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-04-10 14:39:39 +02:00
arch KVM: SVM: Don't change target vCPU state on AP Creation VMGEXIT error 2025-04-10 14:39:38 +02:00
block block: fix 'kmem_cache of name 'bio-108' already exists' 2025-03-22 12:54:21 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: api - Fix larval relookup type and mask 2025-04-10 14:39:20 +02:00
Documentation dt-bindings: vendor-prefixes: add GOcontroll 2025-04-10 14:39:13 +02:00
drivers mmc: sdhci-omap: Disable MMC_CAP_AGGRESSIVE_PM for eMMC/SD 2025-04-10 14:39:38 +02:00
fs exfat: fix potential wrong error return from get_block 2025-04-10 14:39:39 +02:00
include uprobes/x86: Harden uretprobe syscall trampoline check 2025-04-10 14:39:37 +02:00
init rust: Disallow BTF generation with Rust + LTO 2025-03-22 12:54:23 -07:00
io_uring io_uring/net: fix sendzc double notif flush 2025-03-28 22:03:32 +01:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel tracing: Fix use-after-free in print_graph_function_flags during tracer switching 2025-04-10 14:39:39 +02:00
lib rust: fix signature of rust_fmt_argument 2025-04-10 14:39:20 +02:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm x86/mm/pat: Fix VM_PAT handling when fork() fails in copy_page_range() 2025-04-10 14:39:18 +02:00
net wifi: mac80211: Fix sparse warning for monitor_sdata 2025-04-10 14:39:36 +02:00
rust rust: Fix enabling Rust and building with GCC for LoongArch 2025-04-10 14:39:36 +02:00
samples rust: treewide: switch to the kernel Vec type 2025-03-13 13:01:46 +01:00
scripts kbuild: deb-pkg: don't set KBUILD_BUILD_VERSION unconditionally 2025-04-10 14:39:35 +02:00
security smack: ipv4/ipv6: tcp/dccp/sctp: fix incorrect child socket label 2025-04-10 14:39:10 +02:00
sound ALSA: hda/realtek: Fix built-in mic on another ASUS VivoBook model 2025-04-10 14:39:33 +02:00
tools tools/power turbostat: report CoreThr per measurement interval 2025-04-10 14:39:35 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-13 13:02:18 +01:00
virt KVM: x86: switch hugepage recovery thread to vhost_task 2024-12-05 14:02:43 +01:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: enable Clippy's check-private-items 2025-03-13 13:01:42 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -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 self from DSA entry 2024-11-03 12:52:38 -08:00
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 MAINTAINERS: add entry for the Rust alloc module 2025-03-13 13:01:47 +01:00
Makefile Linux 6.12.22 2025-04-07 10:08:37 +02:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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 reStructuredText 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.