qiurui
/
linux-kernelorg-stable
mirror of https://kernel.googlesource.com/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
1,321,295 Commits 110 Branches 5,412 Tags 3.5 GiB
C 97.4%
Assembly 1%
Shell 0.6%
Python 0.3%
Makefile 0.3%
Other 0.2%
Go to file
Tengda Wu ced94e137e ftrace: Fix potential warning in trace_printk_seq during ftrace_dump 
[ Upstream commit 4013aef2ce ]

When calling ftrace_dump_one() concurrently with reading trace_pipe,
a WARN_ON_ONCE() in trace_printk_seq() can be triggered due to a race
condition.

The issue occurs because:

CPU0 (ftrace_dump)                              CPU1 (reader)
echo z > /proc/sysrq-trigger

!trace_empty(&iter)
trace_iterator_reset(&iter) <- len = size = 0
                                                cat /sys/kernel/tracing/trace_pipe
trace_find_next_entry_inc(&iter)
  __find_next_entry
    ring_buffer_empty_cpu <- all empty
  return NULL

trace_printk_seq(&iter.seq)
  WARN_ON_ONCE(s->seq.len >= s->seq.size)

In the context between trace_empty() and trace_find_next_entry_inc()
during ftrace_dump, the ring buffer data was consumed by other readers.
This caused trace_find_next_entry_inc to return NULL, failing to populate
`iter.seq`. At this point, due to the prior trace_iterator_reset, both
`iter.seq.len` and `iter.seq.size` were set to 0. Since they are equal,
the WARN_ON_ONCE condition is triggered.

Move the trace_printk_seq() into the if block that checks to make sure the
return value of trace_find_next_entry_inc() is non-NULL in
ftrace_dump_one(), ensuring the 'iter.seq' is properly populated before
subsequent operations.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ingo Molnar <mingo@elte.hu>
Link: https://lore.kernel.org/20250822033343.3000289-1-wutengda@huaweicloud.com
Fixes: d769041f86 ("ring_buffer: implement new locking")
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
 		2025-09-04 15:31:43 +02:00
Documentation mptcp: disable add_addr retransmission when timeout is 0 2025-08-28 16:31:07 +02:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
arch mips: lantiq: xway: sysctrl: rename the etop node 2025-09-04 15:31:43 +02:00
block block: Introduce bio_needs_zone_write_plugging() 2025-08-20 18:30:51 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: jitter - fix intermediary handling 2025-08-20 18:30:42 +02:00
drivers of: dynamic: Fix use after free in of_changeset_add_prop_helper() 2025-09-04 15:31:43 +02:00
fs alloc_fdtable(): change calling conventions. 2025-08-28 16:31:16 +02:00
include net/mlx5: Add IFC bits and enums for buf_ownership 2025-08-28 16:31:15 +02:00
init io_uring: fix breakage in EXPERT menu 2025-08-15 12:13:32 +02:00
io_uring io_uring/futex: ensure io_futex_wait() cleans up properly on failure 2025-08-28 16:31:05 +02:00
ipc ipc: fix to protect IPCS lookups using RCU 2025-06-27 11:11:22 +01:00
kernel ftrace: Fix potential warning in trace_printk_seq during ftrace_dump 2025-09-04 15:31:43 +02:00
lib lib/sbitmap: convert shallow_depth from one word to the whole sbitmap 2025-08-20 18:30:49 +02:00
mm mm/memory-failure: fix infinite UCE for VM_PFNMAP pfn 2025-08-28 16:31:05 +02:00
net netfilter: nf_reject: don't leak dst refcount for loopback packets 2025-08-28 16:31:16 +02:00
rust rust: alloc: fix `rusttest` by providing `Cmalloc::aligned_layout` too 2025-08-28 16:31:13 +02:00
samples samples: mei: Fix building on musl libc 2025-08-15 12:13:38 +02:00
scripts kconfig: lxdialog: fix 'space' to (de)select options 2025-08-20 18:30:48 +02:00
security apparmor: Fix 8-byte alignment for initial dfa blob streams 2025-08-28 16:30:56 +02:00
sound ALSA: usb-audio: Use correct sub-type for UAC3 feature unit validation 2025-08-28 16:31:16 +02:00
tools rtla: Check pkg-config install 2025-09-04 15:31:42 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-13 13:02:18 +01:00
virt KVM: Allow CPU to reschedule while setting per-page memory attributes 2025-07-17 18:37:08 +02:00
.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: give Clippy the minimum supported Rust version 2025-08-01 09:48:44 +01:00
.cocciconfig
…
.editorconfig
…
.get_maintainer.ignore
…
.gitattributes
…
.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
…
COPYING
…
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild
…
Kconfig
…
MAINTAINERS MAINTAINERS: Update Alexey Makhalov's email address 2025-05-22 14:29:46 +02:00
Makefile Linux 6.12.44 2025-08-28 16:31:16 +02:00
README
…

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 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.