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Date: Tue, 02 Jan 2024 02:48:27 -0800
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Subject: [syzbot] [nilfs?] KMSAN: uninit-value in nilfs_add_checksums_on_logs (2)
From: syzbot <syzbot+47a017c46edb25eff048@syzkaller.appspotmail.com>
To: konishi.ryusuke@gmail.com, linux-fsdevel@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-nilfs@vger.kernel.org, 
	syzkaller-bugs@googlegroups.com
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Hello,

syzbot found the following issue on:

HEAD commit:    fbafc3e621c3 Merge tag 'for_linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16e43009e80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
dashboard link: https://syzkaller.appspot.com/bug?extid=47a017c46edb25eff048
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/1520f7b6daa4/disk-fbafc3e6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8b490af009d5/vmlinux-fbafc3e6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/202ca200f4a4/bzImage-fbafc3e6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+47a017c46edb25eff048@syzkaller.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+0xbe4/0xf60 fs/nilfs2/segbuf.c:327
 nilfs_segctor_do_construct+0x9eff/0xe050 fs/nilfs2/segment.c:2112
 nilfs_segctor_construct+0x1eb/0xe30 fs/nilfs2/segment.c:2415
 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2523 [inline]
 nilfs_segctor_thread+0xc3f/0x11d0 fs/nilfs2/segment.c:2606
 kthread+0x3ed/0x540 kernel/kthread.c:388
 ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

Uninit was created at:
 __alloc_pages+0x9a4/0xe00 mm/page_alloc.c:4591
 alloc_pages_mpol+0x62b/0x9d0 mm/mempolicy.c:2133
 alloc_pages mm/mempolicy.c:2204 [inline]
 folio_alloc+0x1da/0x380 mm/mempolicy.c:2211
 filemap_alloc_folio+0xa5/0x430 mm/filemap.c:974
 __filemap_get_folio+0xa5a/0x1760 mm/filemap.c:1918
 pagecache_get_page+0x4a/0x1a0 mm/folio-compat.c:99
 grab_cache_page_write_begin+0x55/0x70 mm/folio-compat.c:109
 block_write_begin+0x4f/0x450 fs/buffer.c:2223
 nilfs_write_begin+0xfc/0x200 fs/nilfs2/inode.c:261
 generic_perform_write+0x3f5/0xc40 mm/filemap.c:3918
 __generic_file_write_iter+0x20a/0x460 mm/filemap.c:4013
 generic_file_write_iter+0x103/0x5b0 mm/filemap.c:4039
 __kernel_write_iter+0x329/0x930 fs/read_write.c:517
 dump_emit_page fs/coredump.c:888 [inline]
 dump_user_range+0x593/0xcd0 fs/coredump.c:915
 elf_core_dump+0x528d/0x5a40 fs/binfmt_elf.c:2077
 do_coredump+0x32c9/0x4920 fs/coredump.c:764
 get_signal+0x2185/0x2d10 kernel/signal.c:2890
 arch_do_signal_or_restart+0x53/0xca0 arch/x86/kernel/signal.c:309
 exit_to_user_mode_loop+0xe8/0x320 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0x163/0x220 kernel/entry/common.c:204
 irqentry_exit_to_user_mode+0xd/0x30 kernel/entry/common.c:309
 irqentry_exit+0x16/0x40 kernel/entry/common.c:412
 exc_page_fault+0x246/0x6f0 arch/x86/mm/fault.c:1564
 asm_exc_page_fault+0x2b/0x30 arch/x86/include/asm/idtentry.h:570

CPU: 1 PID: 5307 Comm: segctord Not tainted 6.7.0-rc7-syzkaller-00003-gfbafc3e621c3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
=====================================================


---
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