No description
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Kan Liang 95bbfeb4ff perf/core: Fix the same task check in perf_event_set_output
[ Upstream commit 24d3ae2f37d8bc3c14b31d353c5d27baf582b6a6 ]

The same task check in perf_event_set_output has some potential issues
for some usages.

For the current perf code, there is a problem if using of
perf_event_open() to have multiple samples getting into the same mmap’d
memory when they are both attached to the same process.
https://lore.kernel.org/all/92645262-D319-4068-9C44-2409EF44888E@gmail.com/
Because the event->ctx is not ready when the perf_event_set_output() is
invoked in the perf_event_open().

Besides the above issue, before the commit bd2756811766 ("perf: Rewrite
core context handling"), perf record can errors out when sampling with
a hardware event and a software event as below.
 $ perf record -e cycles,dummy --per-thread ls
 failed to mmap with 22 (Invalid argument)
That's because that prior to the commit a hardware event and a software
event are from different task context.

The problem should be a long time issue since commit c3f00c7027
("perk: Separate find_get_context() from event initialization").

The task struct is stored in the event->hw.target for each per-thread
event. It is a more reliable way to determine whether two events are
attached to the same task.

The event->hw.target was also introduced several years ago by the
commit 50f16a8bf9 ("perf: Remove type specific target pointers"). It
can not only be used to fix the issue with the current code, but also
back port to fix the issues with an older kernel.

Note: The event->hw.target was introduced later than commit
c3f00c7027. The patch may cannot be applied between the commit
c3f00c7027 and commit 50f16a8bf9. Anybody that wants to back-port
this at that period may have to find other solutions.

Fixes: c3f00c7027 ("perf: Separate find_get_context() from event initialization")
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>
Link: https://lkml.kernel.org/r/20230322202449.512091-1-kan.liang@linux.intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-20 12:07:34 +02:00
arch treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD() 2023-04-20 12:07:32 +02:00
block blk-iocost: fix divide by 0 error in calc_lcoefs() 2023-03-11 16:43:54 +01:00
certs
crypto crypto: rsa-pkcs1pad - Use akcipher_request_complete 2023-03-11 16:43:41 +01:00
Documentation docs: Correct missing "d_" prefix for dentry_operations member d_weak_revalidate 2023-03-22 13:28:03 +01:00
drivers tty: serial: fsl_lpuart: avoid checking for transfer complete when UARTCTRL_SBK is asserted in lpuart32_tx_empty 2023-04-20 12:07:34 +02:00
fs nilfs2: fix sysfs interface lifetime 2023-04-20 12:07:34 +02:00
include treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD() 2023-04-20 12:07:32 +02:00
init
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel perf/core: Fix the same task check in perf_event_set_output 2023-04-20 12:07:34 +02:00
lib lib/mpi: Fix buffer overrun when SG is too long 2023-03-11 16:43:38 +01:00
LICENSES
mm mm/thp: check and bail out if page in deferred queue already 2023-03-11 16:44:05 +01:00
net sunrpc: only free unix grouplist after RCU settles 2023-04-20 12:07:33 +02:00
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 keys: Do not cache key in task struct if key is requested from kernel thread 2023-04-05 11:16:37 +02:00
sound ALSA: hda/realtek: Add quirk for Clevo X370SNW 2023-04-20 12:07:34 +02:00
tools selftests/bpf: check that modifier resolves after pointer 2023-04-05 11:16:39 +02:00
usr
virt KVM: Destroy target device if coalesced MMIO unregistration fails 2023-03-11 16:44:01 +01:00
.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 5.4.240 2023-04-05 11:16:46 +02:00
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.