+Matthew for xarray On Tue, Nov 19, 2024 at 5:38 AM syzbot <syzbot+cc36d44ec9f368e443d3@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: cfaaa7d010d1 Merge tag 'net-6.12-rc8' of git://git.kernel... > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=13005cc0580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=d2aeec8c0b2e420c > dashboard link: https://syzkaller.appspot.com/bug?extid=cc36d44ec9f368e443d3 > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-cfaaa7d0.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/63eae0d3e67f/vmlinux-cfaaa7d0.xz > kernel image: https://storage.googleapis.com/syzbot-assets/6495d9e4ddee/bzImage-cfaaa7d0.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+cc36d44ec9f368e443d3@xxxxxxxxxxxxxxxxxxxxxxxxx > > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 16 at io_uring/tctx.c:51 __io_uring_free+0xfa/0x140 io_uring/tctx.c:51 This warning is a check for WARN_ON_ONCE(!xa_empty(&tctx->xa)); and as Jens pointed out, this was triggered after error injection caused a memory allocation inside xa_store() to fail. Is there maybe an issue where xa_store() can fail midway through while allocating memory for the xarray, so that xa_empty() is no longer true even though there is nothing in the xarray? (And if yes, is that working as intended?) > Modules linked in: > CPU: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.12.0-rc7-syzkaller-00125-gcfaaa7d010d1 #0 > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 > RIP: 0010:__io_uring_free+0xfa/0x140 io_uring/tctx.c:51 > Code: 80 7c 25 00 00 74 08 4c 89 f7 e8 a1 8a 49 fd 49 c7 06 00 00 00 00 5b 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc e8 37 ad df fc 90 <0f> 0b 90 e9 6a ff ff ff e8 29 ad df fc 90 0f 0b 90 eb 84 e8 1e ad > RSP: 0018:ffffc900004279b8 EFLAGS: 00010246 > RAX: ffffffff84b53cd9 RBX: ffff88804fc3b8e0 RCX: ffff88801b7e8000 > RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff88801f058000 > RBP: 0000000000000001 R08: ffffffff8154d881 R09: 1ffff11003e0b005 > R10: dffffc0000000000 R11: ffffed1003e0b006 R12: dffffc0000000000 > R13: 1ffff11003e0b120 R14: ffff88801f058900 R15: ffff88804fc3b800 > FS: 0000000000000000(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00005594393ad338 CR3: 000000000e734000 CR4: 0000000000352ef0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > io_uring_free include/linux/io_uring.h:31 [inline] > __put_task_struct+0xd5/0x290 kernel/fork.c:975 > put_task_struct include/linux/sched/task.h:144 [inline] > delayed_put_task_struct+0x125/0x300 kernel/exit.c:228 > rcu_do_batch kernel/rcu/tree.c:2567 [inline] > rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823 > handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 > run_ksoftirqd+0xca/0x130 kernel/softirq.c:927 > smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164 > kthread+0x2f0/0x390 kernel/kthread.c:389 > ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > </TASK> > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup >
