Re: [syzbot] [bcachefs?] KMSAN: uninit-value in bch2_checksum_update

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    614da38e2f7a Merge tag 'hid-for-linus-2024051401' of git:/..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1731aa4a980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f5d2cbf33633f507
dashboard link: https://syzkaller.appspot.com/bug?extid=8d0e17030490d2299222
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=16412bd2980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11c1b1c2980000

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
mounted in repro: https://storage.googleapis.com/syzbot-assets/d711157b6e8c/mount_2.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8d0e17030490d2299222@xxxxxxxxxxxxxxxxxxxxxxxxx

=====================================================
BUG: KMSAN: uninit-value in crc64_be+0x202/0x310 lib/crc64.c:59
 crc64_be+0x202/0x310 lib/crc64.c:59
 bch2_checksum_update+0x15e/0x1d0 fs/bcachefs/checksum.c:87
 bch2_checksum+0x3c5/0x7c0 fs/bcachefs/checksum.c:216
 __bch2_btree_node_write+0x528c/0x67c0 fs/bcachefs/btree_io.c:2151
 bch2_btree_node_write+0xa5/0x2e0 fs/bcachefs/btree_io.c:2288
 btree_node_write_if_need fs/bcachefs/btree_io.h:153 [inline]
 __btree_node_flush+0x4d0/0x640 fs/bcachefs/btree_trans_commit.c:229
 bch2_btree_node_flush0+0x35/0x60 fs/bcachefs/btree_trans_commit.c:238
 journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:553
 __bch2_journal_reclaim+0xd88/0x1610 fs/bcachefs/journal_reclaim.c:685
 bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:727
 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_u64s_small fs/bcachefs/util.h:511 [inline]
 bkey_p_copy fs/bcachefs/bkey.h:46 [inline]
 bch2_sort_keys+0x1b4d/0x2cb0 fs/bcachefs/bkey_sort.c:194
 __bch2_btree_node_write+0x3acd/0x67c0 fs/bcachefs/btree_io.c:2100
 bch2_btree_node_write+0xa5/0x2e0 fs/bcachefs/btree_io.c:2288
 btree_node_write_if_need fs/bcachefs/btree_io.h:153 [inline]
 __btree_node_flush+0x4d0/0x640 fs/bcachefs/btree_trans_commit.c:229
 bch2_btree_node_flush0+0x35/0x60 fs/bcachefs/btree_trans_commit.c:238
 journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:553
 __bch2_journal_reclaim+0xd88/0x1610 fs/bcachefs/journal_reclaim.c:685
 bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:727
 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 created at:
 __kmalloc_large_node+0x231/0x370 mm/slub.c:3994
 __do_kmalloc_node mm/slub.c:4027 [inline]
 __kmalloc_node+0xb10/0x10c0 mm/slub.c:4046
 kmalloc_node include/linux/slab.h:648 [inline]
 kvmalloc_node+0xc0/0x2d0 mm/util.c:634
 kvmalloc include/linux/slab.h:766 [inline]
 btree_bounce_alloc fs/bcachefs/btree_io.c:118 [inline]
 bch2_btree_node_read_done+0x4e68/0x75e0 fs/bcachefs/btree_io.c:1185
 btree_node_read_work+0x8a5/0x1eb0 fs/bcachefs/btree_io.c:1324
 bch2_btree_node_read+0x3d42/0x4b50
 __bch2_btree_root_read fs/bcachefs/btree_io.c:1748 [inline]
 bch2_btree_root_read+0xa6c/0x13d0 fs/bcachefs/btree_io.c:1772
 read_btree_roots+0x454/0xee0 fs/bcachefs/recovery.c:457
 bch2_fs_recovery+0x7b6a/0x93e0 fs/bcachefs/recovery.c:785
 bch2_fs_start+0x7b2/0xbd0 fs/bcachefs/super.c:1043
 bch2_fs_open+0x152a/0x15f0 fs/bcachefs/super.c:2105
 bch2_mount+0x90d/0x1d90 fs/bcachefs/fs.c:1906
 legacy_get_tree+0x114/0x290 fs/fs_context.c:662
 vfs_get_tree+0xa7/0x570 fs/super.c:1779
 do_new_mount+0x71f/0x15e0 fs/namespace.c:3352
 path_mount+0x742/0x1f20 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x725/0x810 fs/namespace.c:3875
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:3875
 x64_sys_call+0x2bf4/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:166
 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: 0 PID: 5054 Comm: bch-reclaim/loo Not tainted 6.9.0-syzkaller-02707-g614da38e2f7a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
=====================================================


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