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Yu Kuai 8d28d0ddb9 md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime
After commit ec6bb299c7 ("md/md-bitmap: add 'sync_size' into struct
md_bitmap_stats"), following panic is reported:

Oops: general protection fault, probably for non-canonical address
RIP: 0010:bitmap_get_stats+0x2b/0xa0
Call Trace:
 <TASK>
 md_seq_show+0x2d2/0x5b0
 seq_read_iter+0x2b9/0x470
 seq_read+0x12f/0x180
 proc_reg_read+0x57/0xb0
 vfs_read+0xf6/0x380
 ksys_read+0x6c/0xf0
 do_syscall_64+0x82/0x170
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Root cause is that bitmap_get_stats() can be called at anytime if mddev
is still there, even if bitmap is destroyed, or not fully initialized.
Deferenceing bitmap in this case can crash the kernel. Meanwhile, the
above commit start to deferencing bitmap->storage, make the problem
easier to trigger.

Fix the problem by protecting bitmap_get_stats() with bitmap_info.mutex.

Cc: stable@vger.kernel.org # v6.12+
Fixes: 32a7627cf3 ("[PATCH] md: optimised resync using Bitmap based intent logging")
Reported-and-tested-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Closes: https://lore.kernel.org/linux-raid/ca3a91a2-50ae-4f68-b317-abd9889f3907@oracle.com/T/#m6e5086c95201135e4941fe38f9efa76daf9666c5
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20250124092055.4050195-1-yukuai1@huaweicloud.com
Signed-off-by: Song Liu <song@kernel.org>
2025-01-24 10:03:32 -08:00
arch A pretty quiet cycle this time around. We have a bunch of new Qualcomm clk 2025-01-22 10:54:18 -08:00
block blk-mq: create correct map for fallback case 2025-01-23 06:34:32 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Kthreads affinity follow either of 4 existing different patterns: 2025-01-21 17:10:05 -08:00
Documentation hid-for-linus-2025012001 2025-01-22 11:56:39 -08:00
drivers md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime 2025-01-24 10:03:32 -08:00
fs lsm/stable-6.14 PR 20250121 2025-01-21 20:03:04 -08:00
include linux_kselftest-kunit-6.14-rc1 2025-01-22 12:32:39 -08:00
init Rust changes for v6.14 2025-01-21 17:48:03 -08:00
io_uring for-6.14/io_uring-20250119 2025-01-20 20:27:33 -08:00
ipc - The series "resource: A couple of cleanups" from Andy Shevchenko 2024-11-25 16:09:48 -08:00
kernel Power management updates for 6.14-rc1 2025-01-22 11:16:14 -08:00
lib linux_kselftest-kunit-6.14-rc1 2025-01-22 12:32:39 -08:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm cachestat: fix page cache statistics permission checking 2025-01-21 20:30:19 -08:00
net Networking changes for 6.14. 2025-01-22 08:28:57 -08:00
rust Networking changes for 6.14. 2025-01-22 08:28:57 -08:00
samples Rust changes for v6.14 2025-01-21 17:48:03 -08:00
scripts Networking changes for 6.14. 2025-01-22 08:28:57 -08:00
security selinux/stable-6.14 PR 20250121 2025-01-21 20:09:14 -08:00
sound i2c-for-6.14-rc1 2025-01-22 10:47:46 -08:00
tools linux_kselftest-nolibc-6.14-rc1 2025-01-22 12:36:16 -08:00
usr kbuild: Drop support for include/asm-<arch> in headers_check.pl 2024-12-21 11:43:17 +09:00
virt VFIO updates for v6.13 2024-11-27 12:57:03 -08:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-01-10 00:17:25 +01:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: use host dylib naming convention to support macOS 2025-01-10 01:01:24 +01:00
.mailmap Networking changes for 6.14. 2025-01-22 08:28:57 -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: remove Andy Gospodarek from bonding 2025-01-09 08:30:01 -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 hid-for-linus-2025012001 2025-01-22 11:56:39 -08:00
Makefile Networking changes for 6.14. 2025-01-22 08:28:57 -08:00
README README: Fix spelling 2024-03-18 03:36:32 -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 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.