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Charan Teja Kalla 250f71a575 dma-buf: ensure unique directory name for dmabuf stats 
commit 370704e707 upstream.

The dmabuf file uses get_next_ino()(through dma_buf_getfile() ->
alloc_anon_inode()) to get an inode number and uses the same as a
directory name under /sys/kernel/dmabuf/buffers/<ino>. This directory is
used to collect the dmabuf stats and it is created through
dma_buf_stats_setup(). At current, failure to create this directory
entry can make the dma_buf_export() to fail.

Now, as the get_next_ino() can definitely give a repetitive inode no
causing the directory entry creation to fail with -EEXIST. This is a
problem on the systems where dmabuf stats functionality is enabled on
the production builds can make the dma_buf_export(), though the dmabuf
memory is allocated successfully, to fail just because it couldn't
create stats entry.

This issue we are able to see on the snapdragon system within 13 days
where there already exists a directory with inode no "122602" so
dma_buf_stats_setup() failed with -EEXIST as it is trying to create
the same directory entry.

To make the dentry name as unique, use the dmabuf fs specific inode
which is based on the simple atomic variable increment. There is tmpfs
subsystem too which relies on its own inode generation rather than
relying on the get_next_ino() for the same reason of avoiding the
duplicate inodes[1].

[1] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/patch/?id=e809d5f0b5c912fe981dce738f3283b2010665f0

Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: <stable@vger.kernel.org> # 5.15.x+
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1652441296-1986-1-git-send-email-quic_charante@quicinc.com
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-25 09:57:29 +02:00
arch arm64: mte: Ensure the cleared tags are visible before setting the PTE 2022-05-25 09:57:28 +02:00
block iocost: don't reset the inuse weight of under-weighted debtors 2022-05-09 09:14:31 +02:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto crypto: xts - Add softdep on ecb 2022-04-08 14:23:55 +02:00
Documentation ext4, doc: fix incorrect h_reserved size 2022-04-27 14:39:01 +02:00
drivers dma-buf: ensure unique directory name for dmabuf stats 2022-05-25 09:57:29 +02:00
fs nilfs2: fix lockdep warnings during disk space reclamation 2022-05-25 09:57:26 +02:00
include dma-buf: fix use of DMA_BUF_SET_NAME_{A,B} in userspace 2022-05-25 09:57:28 +02:00
init init/main.c: return 1 from handled __setup() functions 2022-04-13 20:59:10 +02:00
ipc ipc/sem: do not sleep with a spin lock held 2022-02-08 18:34:03 +01:00
kernel perf: Fix sys_perf_event_open() race against self 2022-05-25 09:57:27 +02:00
lib dim: initialize all struct fields 2022-05-18 10:26:49 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool 2022-05-25 09:57:23 +02:00
net libceph: fix potential use-after-free on linger ping and resends 2022-05-25 09:57:28 +02:00
samples x86: Prepare inline-asm for straight-line-speculation 2022-05-15 20:18:50 +02:00
scripts x86: Add straight-line-speculation mitigation 2022-05-15 20:18:51 +02:00
security selinux: fix bad cleanup on error in hashtab_duplicate() 2022-05-25 09:57:27 +02:00
sound ALSA: hda/realtek: Add quirk for TongFang devices with pop noise 2022-05-25 09:57:27 +02:00
tools tools/virtio: compile with -pthread 2022-05-25 09:57:25 +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: avoid NULL pointer dereference in kvm_dirty_ring_push 2022-04-13 20:59:26 +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 Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.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 MAINTAINERS: adjust file entry for of_net.c after movement 2022-03-08 19:12:53 +01:00
Makefile Linux 5.15.41 2022-05-18 10:26:57 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.