[syzbot] [bcachefs?] KMSAN: uninit-value in bch2_inode_flush_nocow_writes_async

[syzbot <syzbot+917694e2e9db5284865f@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    101b7a97143a Merge tag 'acpi-6.10-rc1' of git://git.kernel..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14d948f2980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7ac2f8c387a23814
dashboard link: https://syzkaller.appspot.com/bug?extid=917694e2e9db5284865f
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4f673334a91c/disk-101b7a97.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8e6db59f4091/vmlinux-101b7a97.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7e5782387c9d/bzImage-101b7a97.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+917694e2e9db5284865f@syzkaller.appspotmail.com

bcachefs (loop0): snapshots_read... done
bcachefs (loop0): journal_replay... done
bcachefs (loop0): resume_logged_ops... done
bcachefs (loop0): going read-write
bcachefs (loop0): done starting filesystem
=====================================================
BUG: KMSAN: uninit-value in find_first_bit include/linux/find.h:207 [inline]
BUG: KMSAN: uninit-value in bch2_inode_flush_nocow_writes_async+0x6bd/0x6f0 fs/bcachefs/fs-io.c:64
 find_first_bit include/linux/find.h:207 [inline]
 bch2_inode_flush_nocow_writes_async+0x6bd/0x6f0 fs/bcachefs/fs-io.c:64
 bch2_inode_flush_nocow_writes fs/bcachefs/fs-io.c:99 [inline]
 bch2_flush_inode+0x3d4/0x480 fs/bcachefs/fs-io.c:186
 bch2_fsync+0x1d1/0x2a0 fs/bcachefs/fs-io.c:203
 vfs_fsync_range+0x20d/0x270 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2811 [inline]
 bch2_buffered_write fs/bcachefs/fs-io-buffered.c:1136 [inline]
 bch2_write_iter+0xe59/0x5b30 fs/bcachefs/fs-io-buffered.c:1144
 do_iter_readv_writev+0x7e6/0x960
 vfs_writev+0x574/0x1450 fs/read_write.c:971
 do_pwritev fs/read_write.c:1072 [inline]
 __do_compat_sys_pwritev2 fs/read_write.c:1218 [inline]
 __se_compat_sys_pwritev2+0x2a8/0x490 fs/read_write.c:1210
 __ia32_compat_sys_pwritev2+0x11d/0x1a0 fs/read_write.c:1210
 ia32_sys_call+0x918/0x40a0 arch/x86/include/generated/asm/syscalls_32.h:380
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xb4/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:411
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:449
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3877 [inline]
 slab_alloc_node mm/slub.c:3918 [inline]
 kmem_cache_alloc+0x5b9/0xc20 mm/slub.c:3925
 bch2_alloc_inode+0x56/0x280 fs/bcachefs/fs.c:1497
 alloc_inode+0x86/0x460 fs/inode.c:261
 new_inode_pseudo fs/inode.c:1007 [inline]
 new_inode+0x38/0x4f0 fs/inode.c:1033
 bch2_new_inode+0xc8/0x290 fs/bcachefs/fs.c:224
 bch2_lookup_trans fs/bcachefs/fs.c:408 [inline]
 bch2_lookup+0x1993/0x1fc0 fs/bcachefs/fs.c:437
 lookup_open fs/namei.c:3483 [inline]
 open_last_lookups fs/namei.c:3574 [inline]
 path_openat+0x27a9/0x5b00 fs/namei.c:3804
 do_filp_open+0x20e/0x590 fs/namei.c:3834
 do_sys_openat2+0x1bf/0x2f0 fs/open.c:1406
 do_sys_open fs/open.c:1421 [inline]
 __do_compat_sys_openat fs/open.c:1481 [inline]
 __se_compat_sys_openat fs/open.c:1479 [inline]
 __ia32_compat_sys_openat+0x298/0x300 fs/open.c:1479
 ia32_sys_call+0x38e1/0x40a0 arch/x86/include/generated/asm/syscalls_32.h:296
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xb4/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:411
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:449
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

CPU: 0 PID: 15357 Comm: syz-executor.0 Not tainted 6.9.0-syzkaller-02339-g101b7a97143a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
=====================================================


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