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Yongpeng Yang 1e39da974c fscrypt: fix left shift underflow when inode->i_blkbits > PAGE_SHIFT
When simulating an nvme device on qemu with both logical_block_size and
physical_block_size set to 8 KiB, an error trace appears during
partition table reading at boot time. The issue is caused by
inode->i_blkbits being larger than PAGE_SHIFT, which leads to a left
shift of -1 and triggering a UBSAN warning.

[    2.697306] ------------[ cut here ]------------
[    2.697309] UBSAN: shift-out-of-bounds in fs/crypto/inline_crypt.c:336:37
[    2.697311] shift exponent -1 is negative
[    2.697315] CPU: 3 UID: 0 PID: 274 Comm: (udev-worker) Not tainted 6.18.0-rc2+ #34 PREEMPT(voluntary)
[    2.697317] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[    2.697320] Call Trace:
[    2.697324]  <TASK>
[    2.697325]  dump_stack_lvl+0x76/0xa0
[    2.697340]  dump_stack+0x10/0x20
[    2.697342]  __ubsan_handle_shift_out_of_bounds+0x1e3/0x390
[    2.697351]  bh_get_inode_and_lblk_num.cold+0x12/0x94
[    2.697359]  fscrypt_set_bio_crypt_ctx_bh+0x44/0x90
[    2.697365]  submit_bh_wbc+0xb6/0x190
[    2.697370]  block_read_full_folio+0x194/0x270
[    2.697371]  ? __pfx_blkdev_get_block+0x10/0x10
[    2.697375]  ? __pfx_blkdev_read_folio+0x10/0x10
[    2.697377]  blkdev_read_folio+0x18/0x30
[    2.697379]  filemap_read_folio+0x40/0xe0
[    2.697382]  filemap_get_pages+0x5ef/0x7a0
[    2.697385]  ? mmap_region+0x63/0xd0
[    2.697389]  filemap_read+0x11d/0x520
[    2.697392]  blkdev_read_iter+0x7c/0x180
[    2.697393]  vfs_read+0x261/0x390
[    2.697397]  ksys_read+0x71/0xf0
[    2.697398]  __x64_sys_read+0x19/0x30
[    2.697399]  x64_sys_call+0x1e88/0x26a0
[    2.697405]  do_syscall_64+0x80/0x670
[    2.697410]  ? __x64_sys_newfstat+0x15/0x20
[    2.697414]  ? x64_sys_call+0x204a/0x26a0
[    2.697415]  ? do_syscall_64+0xb8/0x670
[    2.697417]  ? irqentry_exit_to_user_mode+0x2e/0x2a0
[    2.697420]  ? irqentry_exit+0x43/0x50
[    2.697421]  ? exc_page_fault+0x90/0x1b0
[    2.697422]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[    2.697425] RIP: 0033:0x75054cba4a06
[    2.697426] Code: 5d e8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 75 19 83 e2 39 83 fa 08 75 11 e8 26 ff ff ff 66 0f 1f 44 00 00 48 8b 45 10 0f 05 <48> 8b 5d f8 c9 c3 0f 1f 40 00 f3 0f 1e fa 55 48 89 e5 48 83 ec 08
[    2.697427] RSP: 002b:00007fff973723a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
[    2.697430] RAX: ffffffffffffffda RBX: 00005ea9a2c02760 RCX: 000075054cba4a06
[    2.697432] RDX: 0000000000002000 RSI: 000075054c190000 RDI: 000000000000001b
[    2.697433] RBP: 00007fff973723c0 R08: 0000000000000000 R09: 0000000000000000
[    2.697434] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
[    2.697434] R13: 00005ea9a2c027c0 R14: 00005ea9a2be5608 R15: 00005ea9a2be55f0
[    2.697436]  </TASK>
[    2.697436] ---[ end trace ]---

This situation can happen for block devices because when
CONFIG_TRANSPARENT_HUGEPAGE is enabled, the maximum logical_block_size
is 64 KiB. set_init_blocksize() then sets the block device
inode->i_blkbits to 13, which is within this limit.

File I/O does not trigger this problem because for filesystems that do
not support the FS_LBS feature, sb_set_blocksize() prevents
sb->s_blocksize_bits from being larger than PAGE_SHIFT. During inode
allocation, alloc_inode()->inode_init_always() assigns inode->i_blkbits
from sb->s_blocksize_bits. Currently, only xfs_fs_type has the FS_LBS
flag, and since xfs I/O paths do not reach submit_bh_wbc(), it does not
hit the left-shift underflow issue.

Signed-off-by: Yongpeng Yang <yangyongpeng@xiaomi.com>
Fixes: 47dd675323 ("block/bdev: lift block size restrictions to 64k")
Cc: stable@vger.kernel.org
[EB: use folio_pos() and consolidate the two shifts by i_blkbits]
Link: https://lore.kernel.org/r/20251105003642.42796-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
2025-11-04 16:37:38 -08:00
arch Miscellaneous fixes: 2025-11-01 10:20:07 -07:00
block block-6.18-20251031 2025-10-31 12:57:19 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push contains the following changes: 2025-10-10 08:56:16 -07:00
Documentation sound fixes for 6.18-rc4 2025-10-31 07:29:09 -07:00
drivers spi: Fix for v6.18 2025-11-01 10:50:43 -07:00
fs fscrypt: fix left shift underflow when inode->i_blkbits > PAGE_SHIFT 2025-11-04 16:37:38 -08:00
include regmap: Fixes for v6.18 2025-11-01 10:45:39 -07:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring: fix buffer auto-commit for multishot uring_cmd 2025-10-23 19:41:31 -06:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel bpf-fixes 2025-10-31 18:22:26 -07:00
lib Second round of Kbuild fixes for 6.19 2025-11-01 10:00:53 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm slab fixes for 6.18-rc3 2025-10-24 12:40:51 -07:00
net bpf-fixes 2025-10-31 18:22:26 -07:00
rust Driver core fixes for 6.18-rc3 2025-10-25 11:03:46 -07:00
samples Char/Misc/IIO/Binder changes for 6.18-rc1 2025-10-04 16:26:32 -07:00
scripts kconfig/nconf: Initialize the default locale at startup 2025-11-01 00:23:22 -04:00
security integrity-v6.18 2025-10-05 10:48:33 -07:00
sound ASoC: Fixes for v6.18 2025-10-30 13:08:08 +01:00
tools objtool: Fix skip_alt_group() for non-alternative STAC/CLAC 2025-11-01 07:43:20 +01:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM x86 fixes for 6.18: 2025-10-18 10:25:43 +02:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap linux_kselftest-kunit-fixes-6.18-rc4 2025-10-30 19:11:27 -07:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS MAINTAINERS: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Second round of Kbuild fixes for 6.19 2025-11-01 10:00:53 -07:00
Makefile Linux 6.18-rc4 2025-11-02 11:28:02 -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.