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Long Li 77035e4d27 ext4: fix race in buffer_head read fault injection 
[ Upstream commit 2f3d93e210 ]

When I enabled ext4 debug for fault injection testing, I encountered the
following warning:

  EXT4-fs error (device sda): ext4_read_inode_bitmap:201: comm fsstress:
         Cannot read inode bitmap - block_group = 8, inode_bitmap = 1051
  WARNING: CPU: 0 PID: 511 at fs/buffer.c:1181 mark_buffer_dirty+0x1b3/0x1d0

The root cause of the issue lies in the improper implementation of ext4's
buffer_head read fault injection. The actual completion of buffer_head
read and the buffer_head fault injection are not atomic, which can lead
to the uptodate flag being cleared on normally used buffer_heads in race
conditions.

[CPU0]           [CPU1]         [CPU2]
ext4_read_inode_bitmap
  ext4_read_bh()
  <bh read complete>
                 ext4_read_inode_bitmap
                   if (buffer_uptodate(bh))
                     return bh
                               jbd2_journal_commit_transaction
                                 __jbd2_journal_refile_buffer
                                   __jbd2_journal_unfile_buffer
                                     __jbd2_journal_temp_unlink_buffer
  ext4_simulate_fail_bh()
    clear_buffer_uptodate
                                      mark_buffer_dirty
                                        <report warning>
                                        WARN_ON_ONCE(!buffer_uptodate(bh))

The best approach would be to perform fault injection in the IO completion
callback function, rather than after IO completion. However, the IO
completion callback function cannot get the fault injection code in sb.

Fix it by passing the result of fault injection into the bh read function,
we simulate faults within the bh read function itself. This requires adding
an extra parameter to the bh read functions that need fault injection.

Fixes: 46f870d690 ("ext4: simulate various I/O and checksum errors when reading metadata")
Signed-off-by: Long Li <leo.lilong@huawei.com>
Link: https://patch.msgid.link/20240906091746.510163-1-leo.lilong@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2024-12-09 10:31:46 +01:00
arch s390/syscalls: Avoid creation of arch/arch/ directory 2024-12-09 10:31:45 +01:00
block block: fix bio_split_rw_at to take zone_write_granularity into account 2024-12-09 10:31:45 +01:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: api - Fix liveliness check in crypto_alg_tested 2024-11-17 15:08:56 +01:00
Documentation can: j1939: fix error in J1939 documentation. 2024-12-09 10:31:38 +01:00
drivers acpi/arm64: Adjust error handling procedure in gtdt_parse_timer_block() 2024-12-09 10:31:44 +01:00
fs ext4: fix race in buffer_head read fault injection 2024-12-09 10:31:46 +01:00
include bpf: support non-r10 register spill/fill to/from stack in precision tracking 2024-12-09 10:31:42 +01:00
init initramfs: avoid filename buffer overrun 2024-12-09 10:31:44 +01:00
io_uring io_uring: fix possible deadlock in io_register_iowq_max_workers() 2024-11-17 15:08:58 +01:00
ipc sysctl: treewide: drop unused argument ctl_table_root::set_ownership(table) 2024-08-11 12:47:13 +02:00
kernel bpf: support non-r10 register spill/fill to/from stack in precision tracking 2024-12-09 10:31:42 +01:00
lib lib/buildid: Fix build ID parsing logic 2024-11-22 15:38:36 +01:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/damon/core: copy nr_accesses when splitting region 2024-11-22 15:38:37 +01:00
net mptcp: fix possible integer overflow in mptcp_reset_tout_timer 2024-12-09 10:31:42 +01:00
rust rust: sync: require T: Sync for LockedBy::access 2024-10-10 11:57:44 +02:00
samples samples: pktgen: correct dev to DEV 2024-11-22 15:38:32 +01:00
scripts kconfig: qconf: fix buffer overflow in debug links 2024-10-10 11:58:01 +02:00
security ima: fix buffer overrun in ima_eventdigest_init_common 2024-11-22 15:38:34 +01:00
sound ALSA: usb-audio: Fix Yamaha P-125 Quirk Entry 2024-12-09 10:31:40 +01:00
tools kselftest/arm64: mte: fix printf type warnings about longs 2024-12-09 10:31:43 +01:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt KVM: Use dedicated mutex to protect kvm_usage_count to avoid deadlock 2024-10-04 16:29:47 +02:00
.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 Remove *.orig pattern from .gitignore 2024-10-04 16:29:44 +02:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.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 USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
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 membarrier: riscv: Add full memory barrier in switch_mm() 2024-09-12 11:11:45 +02:00
Makefile Linux 6.6.63 2024-11-22 15:38:37 +01:00
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.