[syzbot] [bcachefs?] KMSAN: uninit-value in __bch2_bkey_cmp_left_packed

[syzbot <syzbot+ed0bdc5b29ea2e281a83@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    8faabc041a00 Merge tag 'net-6.13-rc4' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10099cf8580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=caeefc00e8b4dc9f
dashboard link: https://syzkaller.appspot.com/bug?extid=ed0bdc5b29ea2e281a83
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=131100c4580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d3426cd3c012/disk-8faabc04.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c05067e0c579/vmlinux-8faabc04.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4788f870d98f/bzImage-8faabc04.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/71ea5ea439f5/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ed0bdc5b29ea2e281a83@syzkaller.appspotmail.com

 done
bcachefs (loop3): going read-write
bcachefs (loop3): journal_replay...
=====================================================
BUG: KMSAN: uninit-value in packed_to_bkey_c fs/bcachefs/bkey.h:251 [inline]
BUG: KMSAN: uninit-value in __bch2_bkey_cmp_left_packed+0x256/0x770 fs/bcachefs/bkey.c:1046
 packed_to_bkey_c fs/bcachefs/bkey.h:251 [inline]
 __bch2_bkey_cmp_left_packed+0x256/0x770 fs/bcachefs/bkey.c:1046
 bkey_cmp_left_packed fs/bcachefs/bkey.h:88 [inline]
 bkey_iter_pos_cmp fs/bcachefs/bset.h:391 [inline]
 btree_path_advance_to_pos fs/bcachefs/btree_iter.c:599 [inline]
 __bch2_btree_path_set_pos+0x1a9b/0x1ec0 fs/bcachefs/btree_iter.c:1301
 bch2_btree_path_set_pos fs/bcachefs/btree_iter.h:229 [inline]
 bch2_btree_iter_traverse+0x8d0/0x1020 fs/bcachefs/btree_iter.c:1875
 wb_flush_one fs/bcachefs/btree_write_buffer.c:149 [inline]
 bch2_btree_write_buffer_flush_locked+0x28d3/0x7090 fs/bcachefs/btree_write_buffer.c:379
 btree_write_buffer_flush_seq+0x2ec7/0x30b0 fs/bcachefs/btree_write_buffer.c:517
 bch2_btree_write_buffer_journal_flush+0x103/0x1f0 fs/bcachefs/btree_write_buffer.c:533
 journal_flush_pins+0xce6/0x1780 fs/bcachefs/journal_reclaim.c:565
 journal_flush_done+0xe1/0x3f0 fs/bcachefs/journal_reclaim.c:819
 bch2_journal_flush_pins+0x2a9/0x3b0 fs/bcachefs/journal_reclaim.c:852
 bch2_journal_flush_all_pins fs/bcachefs/journal_reclaim.h:76 [inline]
 bch2_journal_replay+0x4937/0x4d30 fs/bcachefs/recovery.c:383
 bch2_run_recovery_pass fs/bcachefs/recovery_passes.c:191 [inline]
 bch2_run_recovery_passes+0xaf9/0xf80 fs/bcachefs/recovery_passes.c:244
 bch2_fs_recovery+0x447b/0x5b00 fs/bcachefs/recovery.c:861
 bch2_fs_start+0x7b2/0xbd0 fs/bcachefs/super.c:1037
 bch2_fs_get_tree+0x13ea/0x22d0 fs/bcachefs/fs.c:2170
 vfs_get_tree+0xb1/0x5a0 fs/super.c:1814
 do_new_mount+0x71f/0x15e0 fs/namespace.c:3507
 path_mount+0x742/0x1f10 fs/namespace.c:3834
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x722/0x810 fs/namespace.c:4034
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4034
 x64_sys_call+0x39bf/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 ___kmalloc_large_node+0x22c/0x370 mm/slub.c:4253
 __kmalloc_large_node_noprof+0x3f/0x1e0 mm/slub.c:4270
 __do_kmalloc_node mm/slub.c:4286 [inline]
 __kmalloc_node_noprof+0xc96/0x1250 mm/slub.c:4304
 __kvmalloc_node_noprof+0xc0/0x2d0 mm/util.c:650
 btree_node_data_alloc fs/bcachefs/btree_cache.c:153 [inline]
 __bch2_btree_node_mem_alloc+0x2be/0xa80 fs/bcachefs/btree_cache.c:198
 bch2_fs_btree_cache_init+0x4e4/0xb50 fs/bcachefs/btree_cache.c:653
 bch2_fs_alloc fs/bcachefs/super.c:917 [inline]
 bch2_fs_open+0x4d3a/0x5b40 fs/bcachefs/super.c:2065
 bch2_fs_get_tree+0x983/0x22d0 fs/bcachefs/fs.c:2157
 vfs_get_tree+0xb1/0x5a0 fs/super.c:1814
 do_new_mount+0x71f/0x15e0 fs/namespace.c:3507
 path_mount+0x742/0x1f10 fs/namespace.c:3834
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x722/0x810 fs/namespace.c:4034
 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4034
 x64_sys_call+0x39bf/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 6246 Comm: syz.3.37 Not tainted 6.13.0-rc3-syzkaller-00136-g8faabc041a00 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
=====================================================


---
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