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Filename Latest commit message Latest commit date
Filipe Manana 2daa2a8e89 btrfs: fix data race at btrfs_use_block_rsv() when accessing block reserve
[ Upstream commit c7bb26b847e5b97814f522686068c5628e2b3646 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:22:13 -04:00
arch parisc/ftrace: add missing CONFIG_DYNAMIC_FTRACE check 2024-03-26 18:22:12 -04:00
block block: sed-opal: handle empty atoms when parsing response 2024-03-26 18:22:12 -04:00
certs
crypto crypto: api - Disallow identical driver names 2024-02-23 08:24:48 +01:00
Documentation net: sysfs: Fix /sys/class/net/<iface> path 2024-02-23 08:25:05 +01:00
drivers dm-verity, dm-crypt: align "struct bvec_iter" correctly 2024-03-26 18:22:12 -04:00
fs btrfs: fix data race at btrfs_use_block_rsv() when accessing block reserve 2024-03-26 18:22:13 -04:00
include io_uring/unix: drop usage of io_uring socket 2024-03-26 18:22:12 -04:00
init rootfs: Fix support for rootfstype= when root= is given 2024-01-25 14:34:30 -08:00
ipc
kernel getrusage: use sig->stats_lock rather than lock_task_sighand() 2024-03-15 10:48:19 -04:00
lib ida: Fix crash in ida_free when the bitmap is empty 2024-01-25 14:34:21 -08:00
LICENSES
mm userfaultfd: fix mmap_changing checking in mfill_atomic_hugetlb 2024-03-01 13:13:33 +01:00
net net/iucv: fix the allocation size of iucv_path_table array 2024-03-26 18:22:12 -04:00
samples
scripts scripts/bpf: Fix xdp_md forward declaration typo 2024-03-01 13:13:38 +01:00
security lsm: new security_file_ioctl_compat() hook 2024-02-23 08:25:15 +01:00
sound ASoC: rt5645: Make LattePanda board DMI match more precise 2024-03-26 18:22:12 -04:00
tools selftests: tls: use exact comparison in recv_partial 2024-03-26 18:22:12 -04:00
usr
virt KVM: arm64: vgic-its: Test for valid IRQ in MOVALL handler 2024-03-01 13:13:32 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.272 2024-03-15 14:40:56 -04:00
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.