[syzbot ci] Re: net/rds: replace tasklets with workqueue

[syzbot ci]

syzbot ci has tested the following series

[v1] net/rds: replace tasklets with workqueue
https://lore.kernel.org/all/6b07af04b3ba66a09009e1a0a7b98ec5e...@google.com
* [PATCH net-next] net/rds: replace tasklets with workqueue

and found the following issue:
WARNING in __alloc_workqueue

Full report is available here:
https://ci.syzbot.org/series/e7102860-1b25-4e10-b653-afe8e9820ef8

***

WARNING in __alloc_workqueue

tree: net-next
URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/netdev/net-next.git
base: 42a9fb3382fc2573e92f41d203b095d9a372cfc9
arch: amd64
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
config: https://ci.syzbot.org/builds/220e9c3a-eede-449e-8bb1-d34ad95dc867/config

gre: GRE over IPv4 demultiplexer driver
ip_gre: GRE over IPv4 tunneling driver
IPv4 over IPsec tunneling driver
Initializing XFRM netlink socket
IPsec XFRM device driver
xfrm_iptfs: IPsec IP-TFS tunnel mode module
NET: Registered PF_INET6 protocol family
Segment Routing with IPv6
RPL Segment Routing with IPv6
In-situ OAM (IOAM) with IPv6
mip6: Mobile IPv6
sit: IPv6, IPv4 and MPLS over IPv4 tunneling driver
ip6_gre: GRE over IPv6 tunneling driver
NET: Registered PF_PACKET protocol family
PFKEY is deprecated and scheduled to be removed in 2027, please contact the netdev mailing list
NET: Registered PF_KEY protocol family
Bridge firewalling registered
NET: Registered PF_X25 protocol family
X25: Linux Version 0.2
can: controller area network core
NET: Registered PF_CAN protocol family
can: raw protocol
can: broadcast manager protocol
can: netlink gateway - max_hops=1
can: SAE J1939
can: isotp protocol (max_pdu_size 8300)
Bluetooth: RFCOMM TTY layer initialized
Bluetooth: RFCOMM socket layer initialized
Bluetooth: RFCOMM ver 1.11
Bluetooth: BNEP (Ethernet Emulation) ver 1.3
Bluetooth: BNEP filters: protocol multicast
Bluetooth: BNEP socket layer initialized
Bluetooth: HIDP (Human Interface Emulation) ver 1.2
Bluetooth: HIDP socket layer initialized
NET: Registered PF_RXRPC protocol family
Key type rxrpc registered
Key type rxrpc_s registered
NET: Registered PF_KCM protocol family
l2tp_core: L2TP core driver, V2.0
l2tp_ppp: PPPoL2TP kernel driver, V2.0
l2tp_ip: L2TP IP encapsulation support (L2TPv3)
l2tp_netlink: L2TP netlink interface
l2tp_eth: L2TP ethernet pseudowire support (L2TPv3)
l2tp_ip6: L2TP IP encapsulation support for IPv6 (L2TPv3)
NET: Registered PF_PHONET protocol family
8021q: 802.1Q VLAN Support v1.8
sctp: Hash tables configured (bind 32/56)
NET: Registered PF_RDS protocol family
------------[ cut here ]------------
workqueue: rds_ib_wq is using neither WQ_PERCPU or WQ_UNBOUND. Setting WQ_PERCPU.
WARNING: kernel/workqueue.c:5939 at __alloc_workqueue+0x1cd2/0x1fe0, CPU#1: swapper/0/1
Modules linked in:
CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:__alloc_workqueue+0x1cd5/0x1fe0
Code: 0b 90 e9 6d fc ff ff e8 89 02 39 00 e9 7f fb ff ff e8 7f 02 39 00 e9 85 fb ff ff e8 75 02 39 00 48 8d 3d ce 68 ee 0e 4c 89 f6 <67> 48 0f b9 3a 41 81 cf 00 01 00 00 e9 10 e6 ff ff e8 55 02 39 00
RSP: 0000:ffffc900000676a8 EFLAGS: 00010293
RAX: ffffffff818ed98b RBX: 0000000000000000 RCX: ffff888102adda00
RDX: 0000000000000000 RSI: ffff888173f5d170 RDI: ffffffff907d4260
RBP: ffffffff8d43a5a0 R08: ffff888102adda00 R09: 0000000000000002
R10: 0000000000000102 R11: 0000000000000000 R12: ffff888173f5d000
R13: ffff888173f5d000 R14: ffff888173f5d170 R15: 0000000000000018
FS: 0000000000000000(0000) GS:ffff8882a8cc6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000eb48000 CR4: 00000000000006f0
Call Trace:
<TASK>
alloc_workqueue_noprof+0xe3/0x210
rds_ib_init+0x54/0x190
rds_rdma_init+0x74/0x170
do_one_initcall+0x250/0x870
do_initcall_level+0x10a/0x1a0
do_initcalls+0x59/0xa0
kernel_init_freeable+0x29d/0x3e0
kernel_init+0x22/0x1d0
ret_from_fork+0x514/0xb70
ret_from_fork_asm+0x1a/0x30
</TASK>


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
Tested-by: syz...@syzkaller.appspotmail.com

---
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Notes:
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- To test a new version of the whole series, please send it directly
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[Sunny Tiwari]

These issues were present in v1 but have already been addressed in my v2 submission.
https://lore.kernel.org/linux-rdma/0a141f59b37b9055764c97d...@kernel.org/T/#t