linux-kernel - [syzbot] [nilfs?] KMSAN: uninit-value in nilfs_add_checksums_on

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Date: Sat, 15 Jun 2024 12:43:17 -0700
From: syzbot <syzbot+206133fb2e7b32bba4be@...kaller.appspotmail.com>
To: konishi.ryusuke@...il.com, linux-kernel@...r.kernel.org, 
	linux-nilfs@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [nilfs?] KMSAN: uninit-value in nilfs_add_checksums_on_logs (3)

Hello,

syzbot found the following issue on:

HEAD commit:    614da38e2f7a Merge tag 'hid-for-linus-2024051401' of git:/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12d26ada980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f5d2cbf33633f507
dashboard link: https://syzkaller.appspot.com/bug?extid=206133fb2e7b32bba4be
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/89eafb874b71/disk-614da38e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/356000512ad9/vmlinux-614da38e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/839c73939115/bzImage-614da38e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+206133fb2e7b32bba4be@...kaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in crc32_body lib/crc32.c:110 [inline]
BUG: KMSAN: uninit-value in crc32_le_generic lib/crc32.c:179 [inline]
BUG: KMSAN: uninit-value in crc32_le_base+0x43c/0xd80 lib/crc32.c:197
 crc32_body lib/crc32.c:110 [inline]
 crc32_le_generic lib/crc32.c:179 [inline]
 crc32_le_base+0x43c/0xd80 lib/crc32.c:197
 nilfs_segbuf_fill_in_data_crc fs/nilfs2/segbuf.c:224 [inline]
 nilfs_add_checksums_on_logs+0xb80/0xe40 fs/nilfs2/segbuf.c:327
 nilfs_segctor_do_construct+0x9876/0xdeb0 fs/nilfs2/segment.c:2078
 nilfs_segctor_construct+0x1eb/0xe30 fs/nilfs2/segment.c:2381
 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2489 [inline]
 nilfs_segctor_thread+0xc50/0x11e0 fs/nilfs2/segment.c:2573
 kthread+0x3e2/0x540 kernel/kthread.c:389
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was stored to memory at:
 memcpy_from_iter lib/iov_iter.c:73 [inline]
 iterate_bvec include/linux/iov_iter.h:122 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:249 [inline]
 iterate_and_advance include/linux/iov_iter.h:271 [inline]
 __copy_from_iter lib/iov_iter.c:249 [inline]
 copy_page_from_iter_atomic+0x12b7/0x2ae0 lib/iov_iter.c:481
 generic_perform_write+0x4c1/0xc60 mm/filemap.c:3982
 __generic_file_write_iter+0x20a/0x460 mm/filemap.c:4069
 generic_file_write_iter+0x103/0x5b0 mm/filemap.c:4095
 __kernel_write_iter+0x64d/0xc80 fs/read_write.c:523
 dump_emit_page fs/coredump.c:895 [inline]
 dump_user_range+0x8dc/0xee0 fs/coredump.c:956
 elf_core_dump+0x57c7/0x5ae0 fs/binfmt_elf.c:2083
 do_coredump+0x32d5/0x4920 fs/coredump.c:769
 get_signal+0x267e/0x2d00 kernel/signal.c:2896
 arch_do_signal_or_restart+0x53/0xcb0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x5d/0x160 kernel/entry/common.c:218
 do_syscall_64+0xdc/0x1e0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_pages+0x9d6/0xe70 mm/page_alloc.c:4598
 alloc_pages_mpol+0x299/0x990 mm/mempolicy.c:2264
 alloc_pages+0x1bf/0x1e0 mm/mempolicy.c:2335
 dump_user_range+0x4a/0xee0 fs/coredump.c:940
 elf_core_dump+0x57c7/0x5ae0 fs/binfmt_elf.c:2083
 do_coredump+0x32d5/0x4920 fs/coredump.c:769
 get_signal+0x267e/0x2d00 kernel/signal.c:2896
 arch_do_signal_or_restart+0x53/0xcb0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x5d/0x160 kernel/entry/common.c:218
 do_syscall_64+0xdc/0x1e0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 PID: 5368 Comm: segctord Not tainted 6.9.0-syzkaller-02707-g614da38e2f7a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
=====================================================


---
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