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

[syzbot <syzbot+681f3c43b6970652376b@syzkaller.appspotmail.com>]

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 output: https://syzkaller.appspot.com/x/log.txt?x=124e4572980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f5d2cbf33633f507
dashboard link: https://syzkaller.appspot.com/bug?extid=681f3c43b6970652376b
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=10b28f42980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=142ddb52980000

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/61af6ba34933/mount_2.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+681f3c43b6970652376b@syzkaller.appspotmail.com

bcachefs (loop0): going read-only
bcachefs (loop0): finished waiting for writes to stop
bcachefs (loop0): flushing journal and stopping allocators, journal seq 12
=====================================================
BUG: KMSAN: uninit-value in bkey_unpack_pos fs/bcachefs/bkey.h:455 [inline]
BUG: KMSAN: uninit-value in rw_aux_tree_set+0x4d2/0x580 fs/bcachefs/bset.c:521
 bkey_unpack_pos fs/bcachefs/bkey.h:455 [inline]
 rw_aux_tree_set+0x4d2/0x580 fs/bcachefs/bset.c:521
 bch2_bset_fix_lookup_table+0x16b2/0x1e90 fs/bcachefs/bset.c:995
 bch2_bset_insert+0x1617/0x19f0 fs/bcachefs/bset.c:1042
 bch2_btree_bset_insert_key+0xf56/0x2b70 fs/bcachefs/btree_trans_commit.c:194
 bch2_btree_insert_key_leaf+0x276/0x1050 fs/bcachefs/btree_trans_commit.c:277
 bch2_trans_commit_write_locked fs/bcachefs/btree_trans_commit.c:744 [inline]
 do_bch2_trans_commit fs/bcachefs/btree_trans_commit.c:854 [inline]
 __bch2_trans_commit+0x98e6/0xab10 fs/bcachefs/btree_trans_commit.c:1093
 bch2_trans_commit fs/bcachefs/btree_update.h:168 [inline]
 btree_key_cache_flush_pos fs/bcachefs/btree_key_cache.c:672 [inline]
 bch2_btree_key_cache_journal_flush+0x10f9/0x1990 fs/bcachefs/btree_key_cache.c:748
 journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:553
 journal_flush_done+0xe1/0x3f0 fs/bcachefs/journal_reclaim.c:806
 bch2_journal_flush_pins+0xdb/0x3b0 fs/bcachefs/journal_reclaim.c:839
 bch2_journal_flush_all_pins fs/bcachefs/journal_reclaim.h:76 [inline]
 __bch2_fs_read_only+0x1b9/0x750 fs/bcachefs/super.c:277
 bch2_fs_read_only+0xcb4/0x1540 fs/bcachefs/super.c:357
 __bch2_fs_stop+0x112/0x6f0 fs/bcachefs/super.c:622
 bch2_put_super+0x3c/0x50 fs/bcachefs/fs.c:1791
 generic_shutdown_super+0x194/0x4c0 fs/super.c:641
 bch2_kill_sb+0x3d/0x70 fs/bcachefs/fs.c:2015
 deactivate_locked_super+0xe0/0x3f0 fs/super.c:472
 deactivate_super+0x14f/0x160 fs/super.c:505
 cleanup_mnt+0x6c6/0x730 fs/namespace.c:1267
 __cleanup_mnt+0x22/0x30 fs/namespace.c:1274
 task_work_run+0x268/0x310 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [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+0xce/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:
 __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: 5060 Comm: syz-executor338 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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