mirrors
/
linux-stable
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
1
0
Fork 0
Code Issues Releases Wiki Activity
1,067,393 Commits 103 Branches 5,015 Tags 5.4 GiB
C 97.6%
Assembly 1%
Shell 0.5%
Python 0.3%
Makefile 0.3%
Go to file
Steven Rostedt (Google) 898127d612 tracing: Use .flush() call to wake up readers 
commit e5d7c19165 upstream.

The .release() function does not get called until all readers of a file
descriptor are finished.

If a thread is blocked on reading a file descriptor in ring_buffer_wait(),
and another thread closes the file descriptor, it will not wake up the
other thread as ring_buffer_wake_waiters() is called by .release(), and
that will not get called until the .read() is finished.

The issue originally showed up in trace-cmd, but the readers are actually
other processes with their own file descriptors. So calling close() would wake
up the other tasks because they are blocked on another descriptor then the
one that was closed(). But there's other wake ups that solve that issue.

When a thread is blocked on a read, it can still hang even when another
thread closed its descriptor.

This is what the .flush() callback is for. Have the .flush() wake up the
readers.

Link: https://lore.kernel.org/linux-trace-kernel/20240308202432.107909457@goodmis.org

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linke li <lilinke99@qq.com>
Cc: Rabin Vincent <rabin@rab.in>
Fixes: f3ddb74ad0 ("tracing: Wake up ring buffer waiters on closing of the file")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 		2024-04-10 16:18:45 +02:00
Documentation x86/cpu: Support AMD Automatic IBRS 2024-04-10 16:18:33 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
arch KVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region() 2024-04-10 16:18:45 +02:00
block block: Clear zone limits for a non-zoned stacked queue 2024-04-10 16:18:35 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: api - Disallow identical driver names 2024-02-23 08:54:23 +01:00
drivers cpufreq: brcmstb-avs-cpufreq: fix up "add check for cpufreq_cpu_get's return value" 2024-04-10 16:18:44 +02:00
fs NFSD: Fix nfsd_clid_class use of __string_len() macro 2024-04-10 16:18:43 +02:00
include Drivers: hv: vmbus: Calculate ring buffer size for more efficient use of memory 2024-04-10 16:18:44 +02:00
init modules: wait do_free_init correctly 2024-03-26 18:21:31 -04:00
io_uring io_uring: don't save/restore iowait state 2024-03-26 18:21:35 -04:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:28:45 +01:00
kernel tracing: Use .flush() call to wake up readers 2024-04-10 16:18:45 +02:00
lib kasan/test: avoid gcc warning for intentional overflow 2024-04-10 16:18:35 +02:00
mm memtest: use {READ,WRITE}_ONCE in memory scanning 2024-04-10 16:18:42 +02:00
net xfrm: Avoid clang fortify warning in copy_to_user_tmpl() 2024-04-10 16:18:45 +02:00
samples samples/hw_breakpoint: fix building without module unloading 2023-09-23 11:10:01 +02:00
scripts kbuild: Move -Wenum-{compare-conditional,enum-conversion} into W=1 2024-04-10 16:18:41 +02:00
security landlock: Warn once if a Landlock action is requested while disabled 2024-04-10 16:18:39 +02:00
sound ALSA: usb-audio: Stop parsing channels bits when all channels are found. 2024-03-26 18:21:32 -04:00
tools selftests/mqueue: Set timeout to 180 seconds 2024-04-10 16:18:35 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Always flush async #PF workqueue when vCPU is being destroyed 2024-04-10 16:18:34 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
…
.get_maintainer.ignore
…
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-26 14:23:27 +02:00
Makefile Linux 5.15.153 2024-03-26 18:23:03 -04:00
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 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.