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Filipe Manana c7bb26b847 btrfs: fix data race at btrfs_use_block_rsv() when accessing block reserve
At btrfs_use_block_rsv() we read the size of a block reserve without
locking its spinlock, which makes KCSAN complain because the size of a
block reserve is always updated while holding its spinlock. The report
from KCSAN is the following:

  [653.313148] BUG: KCSAN: data-race in btrfs_update_delayed_refs_rsv [btrfs] / btrfs_use_block_rsv [btrfs]

  [653.314755] read to 0x000000017f5871b8 of 8 bytes by task 7519 on cpu 0:
  [653.314779]  btrfs_use_block_rsv+0xe4/0x2f8 [btrfs]
  [653.315606]  btrfs_alloc_tree_block+0xdc/0x998 [btrfs]
  [653.316421]  btrfs_force_cow_block+0x220/0xe38 [btrfs]
  [653.317242]  btrfs_cow_block+0x1ac/0x568 [btrfs]
  [653.318060]  btrfs_search_slot+0xda2/0x19b8 [btrfs]
  [653.318879]  btrfs_del_csums+0x1dc/0x798 [btrfs]
  [653.319702]  __btrfs_free_extent.isra.0+0xc24/0x2028 [btrfs]
  [653.320538]  __btrfs_run_delayed_refs+0xd3c/0x2390 [btrfs]
  [653.321340]  btrfs_run_delayed_refs+0xae/0x290 [btrfs]
  [653.322140]  flush_space+0x5e4/0x718 [btrfs]
  [653.322958]  btrfs_preempt_reclaim_metadata_space+0x102/0x2f8 [btrfs]
  [653.323781]  process_one_work+0x3b6/0x838
  [653.323800]  worker_thread+0x75e/0xb10
  [653.323817]  kthread+0x21a/0x230
  [653.323836]  __ret_from_fork+0x6c/0xb8
  [653.323855]  ret_from_fork+0xa/0x30

  [653.323887] write to 0x000000017f5871b8 of 8 bytes by task 576 on cpu 3:
  [653.323906]  btrfs_update_delayed_refs_rsv+0x1a4/0x250 [btrfs]
  [653.324699]  btrfs_add_delayed_data_ref+0x468/0x6d8 [btrfs]
  [653.325494]  btrfs_free_extent+0x76/0x120 [btrfs]
  [653.326280]  __btrfs_mod_ref+0x6a8/0x6b8 [btrfs]
  [653.327064]  btrfs_dec_ref+0x50/0x70 [btrfs]
  [653.327849]  walk_up_proc+0x236/0xa50 [btrfs]
  [653.328633]  walk_up_tree+0x21c/0x448 [btrfs]
  [653.329418]  btrfs_drop_snapshot+0x802/0x1328 [btrfs]
  [653.330205]  btrfs_clean_one_deleted_snapshot+0x184/0x238 [btrfs]
  [653.330995]  cleaner_kthread+0x2b0/0x2f0 [btrfs]
  [653.331781]  kthread+0x21a/0x230
  [653.331800]  __ret_from_fork+0x6c/0xb8
  [653.331818]  ret_from_fork+0xa/0x30

So add a helper to get the size of a block reserve while holding the lock.
Reading the field while holding the lock instead of using the data_race()
annotation is used in order to prevent load tearing.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
History 2024-02-22 12:15:12 +01:00
arch Current release - regressions: 2023-12-14 13:11:49 -08:00
block block-6.7-2023-12-01 2023-12-02 06:39:30 +09:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto This push fixes a regression in ahash and hides the Kconfig sub-options for the jitter RNG. 2023-11-09 17:04:58 -08:00
Documentation fuse fixes for 6.7-rc6 2023-12-12 11:06:41 -08:00
drivers platform-drivers-x86 for v6.7-4 2023-12-14 17:15:33 -08:00
fs btrfs: fix data race at btrfs_use_block_rsv() when accessing block reserve 2024-02-22 12:15:12 +01:00
include btrfs: defrag: reject unknown flags of btrfs_ioctl_defrag_range_args 2024-01-12 02:04:19 +01:00
init As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
io_uring io_uring/af_unix: disable sending io_uring over sockets 2023-12-09 21:20:33 +00:00
ipc Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
kernel - Make sure tasks are thawed exactly and only once to avoid their state 2023-12-10 11:09:16 -08:00
lib 31 hotfixes. 10 of these address pre-6.6 issues and are marked cc:stable. 2023-12-08 08:36:23 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/madvise: add cond_resched() in madvise_cold_or_pageout_pte_range() 2023-12-06 16:12:50 -08:00
net appletalk: Fix Use-After-Free in atalk_ioctl 2023-12-14 12:02:45 +01:00
rust Kbuild updates for v6.7 2023-11-04 08:07:19 -10:00
samples Landlock updates for v6.7-rc1 2023-11-03 09:28:53 -10:00
scripts sign-file: Fix incorrect return values check 2023-12-13 12:55:11 -08:00
security + Features 2023-11-03 09:48:17 -10:00
sound ALSA: hda/realtek: Add quirk for Lenovo Yoga Pro 7 2023-12-07 19:21:08 +01:00
tools Generic: 2023-12-10 10:46:46 -08:00
usr arch: Remove Itanium (IA-64) architecture 2023-09-11 08:13:17 +00:00
virt Revert "KVM: Prevent module exit until all VMs are freed" 2023-12-01 08:12:30 -08:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: generate kernel.spec in rpmbuild/SPECS/ 2023-10-03 20:49:09 +09:00
.mailmap hid-for-linus-2023121201 2023-12-12 17:02:56 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: drop Antti Palosaari 2023-12-06 16:12:49 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Current release - regressions: 2023-12-14 13:11:49 -08:00
Makefile Linux 6.7-rc5 2023-12-10 14:33:40 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.