[syzbot] [io-uring?] KMSAN: uninit-value in xa_find

[syzbot] [io-uring?] KMSAN: uninit-value in xa_find

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    914873bc7df9 Merge tag 'x86-build-2025-05-25' of git://git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14727df4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=19f03604c8d216a8
dashboard link: https://syzkaller.appspot.com/bug?extid=c3ff04150c30d3df0f57
compiler:       Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/624ebec879d9/disk-914873bc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f44c87154c1f/vmlinux-914873bc.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a922731b5aab/bzImage-914873bc.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c3ff04150c30d3df0f57@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in xas_start lib/xarray.c:193 [inline]
BUG: KMSAN: uninit-value in xas_load+0xd20/0xd70 lib/xarray.c:239
 xas_start lib/xarray.c:193 [inline]
 xas_load+0xd20/0xd70 lib/xarray.c:239
 xas_find+0x2c8/0xd40 lib/xarray.c:1406
 xa_find+0x15a/0x2a0 lib/xarray.c:2194
 io_unregister_zcrx_ifqs+0x75/0x1d0 io_uring/zcrx.c:639
 io_ring_ctx_free+0x61/0x740 io_uring/io_uring.c:2723
 io_ring_exit_work+0xdec/0xe20 io_uring/io_uring.c:2963
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd5c/0xf00 kernel/kthread.c:464
 ret_from_fork+0x71/0x90 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Uninit was stored to memory at:
 xa_find+0x26c/0x2a0 lib/xarray.c:2186
 io_unregister_zcrx_ifqs+0x75/0x1d0 io_uring/zcrx.c:639
 io_ring_ctx_free+0x61/0x740 io_uring/io_uring.c:2723
 io_ring_exit_work+0xdec/0xe20 io_uring/io_uring.c:2963
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xb97/0x1d90 kernel/workqueue.c:3319
 worker_thread+0xedf/0x1590 kernel/workqueue.c:3400
 kthread+0xd5c/0xf00 kernel/kthread.c:464
 ret_from_fork+0x71/0x90 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Local variable id created at:
 io_unregister_zcrx_ifqs+0x3d/0x1d0 io_uring/zcrx.c:633
 io_ring_ctx_free+0x61/0x740 io_uring/io_uring.c:2723

CPU: 0 UID: 0 PID: 3749 Comm: kworker/u8:17 Not tainted 6.15.0-syzkaller-01972-g914873bc7df9 #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: iou_exit io_ring_exit_work
=====================================================


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