Re: [syzbot] [bcachefs?] KMSAN: uninit-value in bch2_bkey_val_validate

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    feffde684ac2 Merge tag 'for-6.13-rc1-tag' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1625ade8580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=96ee18b6611821ab
dashboard link: https://syzkaller.appspot.com/bug?extid=09c915024af5057b77da
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=10a390f8580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1125ade8580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b31883c9ce49/disk-feffde68.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cd0fe66ddb61/vmlinux-feffde68.xz
kernel image: https://storage.googleapis.com/syzbot-assets/88e3455fb342/bzImage-feffde68.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/01cd3582aecd/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+09c915024af5057b77da@xxxxxxxxxxxxxxxxxxxxxxxxx

=====================================================
BUG: KMSAN: uninit-value in bch2_backpointer_validate+0x63a/0x8f0 fs/bcachefs/backpointers.c:57
 bch2_backpointer_validate+0x63a/0x8f0 fs/bcachefs/backpointers.c:57
 bch2_bkey_val_validate+0x2b5/0x440 fs/bcachefs/bkey_methods.c:143
 bset_key_validate fs/bcachefs/btree_io.c:841 [inline]
 validate_bset_keys+0x1531/0x2080 fs/bcachefs/btree_io.c:910
 validate_bset_for_write+0x142/0x290 fs/bcachefs/btree_io.c:1942
 __bch2_btree_node_write+0x53df/0x6830 fs/bcachefs/btree_io.c:2152
 bch2_btree_node_write+0x256/0x2e0 fs/bcachefs/btree_io.c:2296
 btree_node_write_if_need fs/bcachefs/btree_io.h:151 [inline]
 __btree_node_flush+0x606/0x680 fs/bcachefs/btree_trans_commit.c:252
 bch2_btree_node_flush1+0x38/0x60 fs/bcachefs/btree_trans_commit.c:266
 journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:565
 __bch2_journal_reclaim+0xda8/0x1670 fs/bcachefs/journal_reclaim.c:698
 bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:740
 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:393 [inline]
 bkey_p_copy fs/bcachefs/bkey.h:47 [inline]
 bch2_sort_keys_keep_unwritten_whiteouts+0x12d5/0x19d0 fs/bcachefs/bkey_sort.c:187
 __bch2_btree_node_write+0x3ae8/0x6830 fs/bcachefs/btree_io.c:2095
 bch2_btree_node_write+0x256/0x2e0 fs/bcachefs/btree_io.c:2296
 btree_node_write_if_need fs/bcachefs/btree_io.h:151 [inline]
 __btree_node_flush+0x606/0x680 fs/bcachefs/btree_trans_commit.c:252
 bch2_btree_node_flush1+0x38/0x60 fs/bcachefs/btree_trans_commit.c:266
 journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:565
 __bch2_journal_reclaim+0xda8/0x1670 fs/bcachefs/journal_reclaim.c:698
 bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:740
 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+0x22c/0x370 mm/slub.c:4238
 __kmalloc_large_node_noprof+0x3f/0x1e0 mm/slub.c:4255
 __do_kmalloc_node mm/slub.c:4271 [inline]
 __kmalloc_node_noprof+0xc96/0x1250 mm/slub.c:4289
 __kvmalloc_node_noprof+0xc0/0x2d0 mm/util.c:650
 btree_bounce_alloc fs/bcachefs/btree_io.c:124 [inline]
 btree_node_sort+0x78a/0x1d30 fs/bcachefs/btree_io.c:323
 bch2_btree_post_write_cleanup+0x1b0/0xf20 fs/bcachefs/btree_io.c:2248
 bch2_btree_node_write+0x21c/0x2e0 fs/bcachefs/btree_io.c:2289
 btree_node_write_if_need fs/bcachefs/btree_io.h:151 [inline]
 __btree_node_flush+0x606/0x680 fs/bcachefs/btree_trans_commit.c:252
 bch2_btree_node_flush0+0x35/0x60 fs/bcachefs/btree_trans_commit.c:261
 journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:565
 __bch2_journal_reclaim+0xda8/0x1670 fs/bcachefs/journal_reclaim.c:698
 bch2_journal_reclaim_thread+0x18e/0x760 fs/bcachefs/journal_reclaim.c:740
 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

CPU: 0 UID: 0 PID: 5790 Comm: bch-reclaim/loo Not tainted 6.13.0-rc1-syzkaller-00025-gfeffde684ac2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
=====================================================


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