[syzbot] [xfs?] KMSAN: uninit-value in xfs_getfsmap_helper

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: eda666ff2276 kmsan: silence -Wmissing-prototypes warnings
git tree: https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=10edfcbd480000
kernel config: https://syzkaller.appspot.com/x/.config?x=f27365aeb365b358
dashboard link: https://syzkaller.appspot.com/bug?extid=090ae72d552e6bd93cfe
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project.git 610139d2d9ce6746b3c617fb3e2f7886272d26ff), GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/fc16035efde4/disk-eda666ff.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/084efc06a321/vmlinux-eda666ff.xz
kernel image: https://storage.googleapis.com/syzbot-assets/35c07fcfcbf2/bzImage-eda666ff.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+090ae7...@syzkaller.appspotmail.com

loop4: detected capacity change from 0 to 32768
XFS (loop4): Mounting V5 Filesystem c496e05e-540d-4c72-b591-04d79d8b4eeb
XFS (loop4): Ending clean mount
=====================================================
BUG: KMSAN: uninit-value in xfs_getfsmap_helper+0xbd5/0x1b20 fs/xfs/xfs_fsmap.c:341
xfs_getfsmap_helper+0xbd5/0x1b20 fs/xfs/xfs_fsmap.c:341
xfs_getfsmap_datadev_bnobt_helper+0x225/0x2d0 fs/xfs/xfs_fsmap.c:385
xfs_getfsmap_datadev_bnobt_query+0xad/0x2e0 fs/xfs/xfs_fsmap.c:744
__xfs_getfsmap_datadev+0x13e8/0x1f70 fs/xfs/xfs_fsmap.c:676
xfs_getfsmap_datadev_bnobt+0x8a/0xd0 fs/xfs/xfs_fsmap.c:765
xfs_getfsmap+0x1690/0x18d0 fs/xfs/xfs_fsmap.c:962
xfs_ioc_getfsmap+0x5e6/0x1080 fs/xfs/xfs_ioctl.c:1558
xfs_file_ioctl+0x1c5/0x27a0 fs/xfs/xfs_ioctl.c:1952
xfs_file_compat_ioctl+0x334/0xbb0
__do_compat_sys_ioctl fs/ioctl.c:968 [inline]
__se_compat_sys_ioctl+0x781/0xfa0 fs/ioctl.c:910
__ia32_compat_sys_ioctl+0x8f/0xd0 fs/ioctl.c:910
do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
__do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
entry_SYSENTER_compat_after_hwframe+0x70/0x82

Uninit was stored to memory at:
xfs_getfsmap_datadev_bnobt_helper+0x29b/0x2d0 fs/xfs/xfs_fsmap.c:380
xfs_getfsmap_datadev_bnobt_query+0xad/0x2e0 fs/xfs/xfs_fsmap.c:744
__xfs_getfsmap_datadev+0x13e8/0x1f70 fs/xfs/xfs_fsmap.c:676
xfs_getfsmap_datadev_bnobt+0x8a/0xd0 fs/xfs/xfs_fsmap.c:765
xfs_getfsmap+0x1690/0x18d0 fs/xfs/xfs_fsmap.c:962
xfs_ioc_getfsmap+0x5e6/0x1080 fs/xfs/xfs_ioctl.c:1558
xfs_file_ioctl+0x1c5/0x27a0 fs/xfs/xfs_ioctl.c:1952
xfs_file_compat_ioctl+0x334/0xbb0
__do_compat_sys_ioctl fs/ioctl.c:968 [inline]
__se_compat_sys_ioctl+0x781/0xfa0 fs/ioctl.c:910
__ia32_compat_sys_ioctl+0x8f/0xd0 fs/ioctl.c:910
do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
__do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
entry_SYSENTER_compat_after_hwframe+0x70/0x82

Local variable akeys created at:
xfs_getfsmap_datadev_bnobt+0x50/0xd0 fs/xfs/xfs_fsmap.c:762
xfs_getfsmap+0x1690/0x18d0 fs/xfs/xfs_fsmap.c:962

CPU: 1 PID: 7205 Comm: syz-executor.4 Not tainted 6.2.0-rc6-syzkaller-80422-geda666ff2276 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
=====================================================


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