Re: [syzbot] [btrfs] KMSAN: uninit-value in __crc32c_le_base (4)

[syzbot <syzbot+549710bad9c798e25b15@syzkaller.appspotmail.com>]

syzbot has found a reproducer for the following issue on:

HEAD commit:    6d7ddd805123 Merge tag 'soc-fixes-6.9-3' of git://git.kern..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1094303f180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=617171361dd3cd47
dashboard link: https://syzkaller.appspot.com/bug?extid=549710bad9c798e25b15
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11047204980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17a2905c980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/49caca594b2f/disk-6d7ddd80.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cad0ed0e7e81/vmlinux-6d7ddd80.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c5403827515b/bzImage-6d7ddd80.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/dfb350d62061/mount_2.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+549710bad9c798e25b15@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 __crc32c_le_base+0x43c/0xd80 lib/crc32.c:201
 crc32_body lib/crc32.c:110 [inline]
 crc32_le_generic lib/crc32.c:179 [inline]
 __crc32c_le_base+0x43c/0xd80 lib/crc32.c:201
 chksum_update+0x5b/0xd0 crypto/crc32c_generic.c:88
 crypto_shash_update+0x79/0xa0 crypto/shash.c:70
 csum_tree_block+0x35f/0x5d0 fs/btrfs/disk-io.c:96
 btree_csum_one_bio+0x4d5/0xeb0 fs/btrfs/disk-io.c:294
 btrfs_bio_csum fs/btrfs/bio.c:538 [inline]
 btrfs_submit_chunk fs/btrfs/bio.c:741 [inline]
 btrfs_submit_bio+0x1eb6/0x2930 fs/btrfs/bio.c:770
 write_one_eb+0x13fa/0x1570 fs/btrfs/extent_io.c:1740
 submit_eb_page fs/btrfs/extent_io.c:1899 [inline]
 btree_write_cache_pages+0x1d2a/0x29a0 fs/btrfs/extent_io.c:1949
 btree_writepages+0x84/0x270 fs/btrfs/disk-io.c:516
 do_writepages+0x427/0xc30 mm/page-writeback.c:2612
 filemap_fdatawrite_wbc+0x1d8/0x270 mm/filemap.c:397
 __filemap_fdatawrite_range mm/filemap.c:430 [inline]
 filemap_fdatawrite_range+0xe1/0x110 mm/filemap.c:448
 btrfs_write_marked_extents+0x2e7/0x620 fs/btrfs/transaction.c:1153
 btrfs_sync_log+0x9fd/0x3830 fs/btrfs/tree-log.c:2969
 btrfs_sync_file+0x144c/0x1c60 fs/btrfs/file.c:1968
 vfs_fsync_range+0x20d/0x270 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2795 [inline]
 btrfs_do_write_iter+0x1c5f/0x2270 fs/btrfs/file.c:1695
 btrfs_file_write_iter+0x38/0x50 fs/btrfs/file.c:1705
 do_iter_readv_writev+0x7e6/0x960
 vfs_writev+0x574/0x1450 fs/read_write.c:971
 do_writev+0x251/0x5c0 fs/read_write.c:1018
 __do_sys_writev fs/read_write.c:1091 [inline]
 __se_sys_writev fs/read_write.c:1088 [inline]
 __x64_sys_writev+0x98/0xe0 fs/read_write.c:1088
 x64_sys_call+0x23dc/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:21
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_pages+0x9d6/0xe70 mm/page_alloc.c:4598
 __alloc_pages_bulk+0x19e/0x21e0 mm/page_alloc.c:4523
 alloc_pages_bulk_array include/linux/gfp.h:202 [inline]
 btrfs_alloc_page_array fs/btrfs/extent_io.c:690 [inline]
 alloc_eb_folio_array+0x19b/0x760 fs/btrfs/extent_io.c:714
 alloc_extent_buffer+0x965/0x3ad0 fs/btrfs/extent_io.c:3849
 btrfs_find_create_tree_block+0x46/0x60 fs/btrfs/disk-io.c:610
 btrfs_init_new_buffer fs/btrfs/extent-tree.c:5071 [inline]
 btrfs_alloc_tree_block+0x35c/0x17c0 fs/btrfs/extent-tree.c:5186
 btrfs_alloc_log_tree_node fs/btrfs/disk-io.c:960 [inline]
 btrfs_add_log_tree+0x1b7/0x7a0 fs/btrfs/disk-io.c:1008
 start_log_trans fs/btrfs/tree-log.c:208 [inline]
 btrfs_log_inode_parent+0x9b6/0x1dd0 fs/btrfs/tree-log.c:7066
 btrfs_log_dentry_safe+0x9a/0x100 fs/btrfs/tree-log.c:7171
 btrfs_sync_file+0x126c/0x1c60 fs/btrfs/file.c:1933
 vfs_fsync_range+0x20d/0x270 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2795 [inline]
 btrfs_do_write_iter+0x1c5f/0x2270 fs/btrfs/file.c:1695
 btrfs_file_write_iter+0x38/0x50 fs/btrfs/file.c:1705
 do_iter_readv_writev+0x7e6/0x960
 vfs_writev+0x574/0x1450 fs/read_write.c:971
 do_writev+0x251/0x5c0 fs/read_write.c:1018
 __do_sys_writev fs/read_write.c:1091 [inline]
 __se_sys_writev fs/read_write.c:1088 [inline]
 __x64_sys_writev+0x98/0xe0 fs/read_write.c:1088
 x64_sys_call+0x23dc/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:21
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 PID: 5036 Comm: syz-executor761 Not tainted 6.9.0-rc7-syzkaller-00023-g6d7ddd805123 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
=====================================================


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