[syzbot] [afs?] [net?] BUG: using smp_processor_id() in preemptible code in radix_tree_node_alloc (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 11028ab62899 Merge tag 'probes-fixes-v7.2-rc5' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=130cec99580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c05be6c9b0d36cb9
dashboard link: https://syzkaller.appspot.com/bug?extid=86abcd2aa855d0add658
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-11028ab6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/511647651d7f/vmlinux-11028ab6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1c76180d0109/bzImage-11028ab6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+86abcd...@syzkaller.appspotmail.com

BUG: using smp_processor_id() in preemptible [00000000] code: krxrpcio/0/5331
caller is radix_tree_node_alloc+0x1b3/0x3a0 lib/radix-tree.c:263
CPU: 0 UID: 0 PID: 5331 Comm: krxrpcio/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
check_preemption_disabled+0xd3/0xe0 lib/smp_processor_id.c:47
radix_tree_node_alloc+0x1b3/0x3a0 lib/radix-tree.c:263
idr_get_free+0x28f/0xa10 lib/radix-tree.c:1506
idr_alloc_u32+0x18a/0x330 lib/idr.c:48
idr_alloc_cyclic+0x9c/0x1b0 lib/idr.c:127
rxrpc_alloc_client_connection net/rxrpc/conn_client.c:165 [inline]
rxrpc_add_conn_to_bundle net/rxrpc/conn_client.c:353 [inline]
rxrpc_bundle_has_space net/rxrpc/conn_client.c:404 [inline]
rxrpc_connect_client_calls+0x74f/0x12c0 net/rxrpc/conn_client.c:524
rxrpc_io_thread+0x2d9a/0x3290 net/rxrpc/io_thread.c:536
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>


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