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Filename Latest commit message Latest commit date
Shiju Jose 56ee31167c tracing: Fix poll() and select() do not work on per_cpu trace_pipe and trace_pipe_raw
commit 3e46d910d8acf94e5360126593b68bf4fee4c4a1 upstream.

poll() and select() on per_cpu trace_pipe and trace_pipe_raw do not work
since kernel 6.1-rc6. This issue is seen after the commit
42fb0a1e84ff525ebe560e2baf9451ab69127e2b ("tracing/ring-buffer: Have
polling block on watermark").

This issue is firstly detected and reported, when testing the CXL error
events in the rasdaemon and also erified using the test application for poll()
and select().

This issue occurs for the per_cpu case, when calling the ring_buffer_poll_wait(),
in kernel/trace/ring_buffer.c, with the buffer_percent > 0 and then wait until the
percentage of pages are available. The default value set for the buffer_percent is 50
in the kernel/trace/trace.c.

As a fix, allow userspace application could set buffer_percent as 0 through
the buffer_percent_fops, so that the task will wake up as soon as data is added
to any of the specific cpu buffer.

Link: https://lore.kernel.org/linux-trace-kernel/20230202182309.742-2-shiju.jose@huawei.com

Cc: <mhiramat@kernel.org>
Cc: <mchehab@kernel.org>
Cc: <linux-edac@vger.kernel.org>
Cc: stable@vger.kernel.org
Fixes: 42fb0a1e84ff5 ("tracing/ring-buffer: Have polling block on watermark")
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-22 12:50:30 +01:00
arch powerpc/imc-pmu: Revert nest_init_lock to being a mutex 2023-02-22 12:50:29 +01:00
block blk-cgroup: fix missing pd_online_fn() while activating policy 2023-02-06 07:52:48 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: tcrypt - Fix multibuffer skcipher speed test mem leak 2023-01-18 11:41:19 +01:00
Documentation docs: Fix path paste-o for /sys/kernel/warn_count 2023-02-06 07:52:50 +01:00
drivers iio:adc:twl6030: Enable measurement of VAC 2023-02-22 12:50:30 +01:00
fs btrfs: zlib: zero-initialize zlib workspace 2023-02-22 12:50:30 +01:00
include mm: hugetlb: proc: check for hugetlb shared PMD in /proc/PID/smaps 2023-02-22 12:50:28 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-08 11:22:59 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel tracing: Fix poll() and select() do not work on per_cpu trace_pipe and trace_pipe_raw 2023-02-22 12:50:30 +01:00
lib netlink: prevent potential spectre v1 gadgets 2023-02-06 07:52:45 +01:00
LICENSES
mm mm: swap: properly update readahead statistics in unuse_pte_range() 2023-02-22 12:50:29 +01:00
net xprtrdma: Fix regbuf data not freed in rpcrdma_req_create() 2023-02-22 12:50:29 +01:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2023-01-18 11:41:26 +01:00
scripts ftrace/scripts: Update the instructions for ftrace-bisect.sh 2023-02-06 07:52:44 +01:00
security tomoyo: fix broken dependency on *.conf.default 2023-02-06 07:52:35 +01:00
sound ALSA: emux: Avoid potential array out-of-bound in snd_emux_xg_control() 2023-02-22 12:50:30 +01:00
tools selftests: net: udpgso_bench_tx: Cater for pending datagrams zerocopy benchmarking 2023-02-22 12:50:25 +01:00
usr
virt KVM: arm64: vgic: Fix exit condition in scan_its_table() 2022-10-29 10:20:35 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS net/phy/mdio-i2c: Move header file to include/linux/mdio 2023-02-06 07:52:46 +01:00
Makefile Linux 5.4.231 2023-02-06 07:52:51 +01:00
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.