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Carlos Maiolino 0a69b6b3a0 tmpfs: fix race on handling dquot rbtree
A syzkaller reproducer found a race while attempting to remove dquot
information from the rb tree.

Fetching the rb_tree root node must also be protected by the
dqopt->dqio_sem, otherwise, giving the right timing, shmem_release_dquot()
will trigger a warning because it couldn't find a node in the tree, when
the real reason was the root node changing before the search starts:

Thread 1				Thread 2
- shmem_release_dquot()			- shmem_{acquire,release}_dquot()

- fetch ROOT				- Fetch ROOT

					- acquire dqio_sem
- wait dqio_sem

					- do something, triger a tree rebalance
					- release dqio_sem

- acquire dqio_sem
- start searching for the node, but
  from the wrong location, missing
  the node, and triggering a warning.

Link: https://lkml.kernel.org/r/20240320124011.398847-1-cem@kernel.org
Fixes: eafc474e20 ("shmem: prepare shmem quota infrastructure")
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reported-by: Ubisectech Sirius <bugreport@ubisectech.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-03-26 11:07:23 -07:00
arch ARM: prctl: reject PR_SET_MDWE on pre-ARMv6 2024-03-26 11:07:22 -07:00
block
certs
crypto RISC-V Patches for the 6.9 Merge Window 2024-03-22 10:41:13 -07:00
Documentation A set of x86 fixes: 2024-03-24 11:13:56 -07:00
drivers EFI fixes for v6.9 #2 2024-03-24 13:54:06 -07:00
fs A patch to minimize blockage when processing very large batches of 2024-03-22 11:15:45 -07:00
include prctl: generalize PR_SET_MDWE support check to be per-arch 2024-03-26 11:07:22 -07:00
init init: open /initrd.image with O_LARGEFILE 2024-03-26 11:07:19 -07:00
io_uring io_uring/sqpoll: early exit thread if task_context wasn't allocated 2024-03-18 20:22:42 -06:00
ipc
kernel prctl: generalize PR_SET_MDWE support check to be per-arch 2024-03-26 11:07:22 -07:00
lib hardening fixes for v6.9-rc1 2024-03-23 08:43:21 -07:00
LICENSES
mm tmpfs: fix race on handling dquot rbtree 2024-03-26 11:07:23 -07:00
net Including fixes from CAN, netfilter, wireguard and IPsec. 2024-03-21 14:50:39 -07:00
rust Kbuild updates for v6.9 2024-03-21 14:41:00 -07:00
samples
scripts LoongArch changes for v6.9 2024-03-22 10:22:45 -07:00
security
sound sound fixes #2 for 6.9-rc2 2024-03-22 09:44:19 -07:00
tools selftests/mm: sigbus-wp test requires UFFD_FEATURE_WP_HUGETLBFS_SHMEM 2024-03-26 11:07:22 -07:00
usr
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.mailmap mailmap: update entry for Leonard Crestez 2024-03-26 11:07:20 -07:00
.rustfmt.toml
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MAINTAINERS MAINTAINERS: remove incorrect M: tag for dm-devel@lists.linux.dev 2024-03-26 11:07:21 -07:00
Makefile Linux 6.9-rc1 2024-03-24 14:10:05 -07:00
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 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.