syzbot
upstream test error: WARNING in rcu_tasks_verify_work_fn
Status:
upstream: reported on 2026/09/15 00:01
Subsystems:
kernel
Labels:
prio:low
[Documentation on labels]
Reported-by: syzbot+9d7ab3bc11055d9740f5@syzkaller.appspotmail.com
First crash: 7d14h, last: 46m
Sample crash report:
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
Registered RDS/infiniband transport
Registered RDS/tcp transport
tipc: Activated (version 2.0.0)
NET: Registered PF_TIPC protocol family
tipc: Started in single node mode
smc: adding smcd device lo without pnetid
NET: Registered PF_SMC protocol family
9pnet: Installing 9P2000 support
NET: Registered PF_IEEE802154 protocol family
Key type dns_resolver registered
Key type ceph registered
libceph: loaded (mon/osd proto 15/24)
batman_adv: B.A.T.M.A.N. advanced syzkaller (compatibility version 15) loaded
openvswitch: Open vSwitch switching datapath
NET: Registered PF_VSOCK protocol family
mpls_gso: MPLS GSO support
IPI shorthand broadcast: enabled
sched_clock: Marking stable (34000030151, 87432703)->(34112638300, -25175446)
call_rcu_tasks() has failed boot-time tests.
rcu_tasks: RTGS_WAIT_SCAN_HOLDOUTS(6) since 48 g:5 i:0 kCuUP l:25
------------[ cut here ]------------
ret < 0
WARNING: kernel/rcu/tasks.h:1541 at rcu_tasks_verify_self_tests kernel/rcu/tasks.h:1541 [inline], CPU#1: swapper/0/1
WARNING: kernel/rcu/tasks.h:1541 at rcu_tasks_verify_work_fn+0x1b6/0x270 kernel/rcu/tasks.h:1553, 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: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:rcu_tasks_verify_self_tests kernel/rcu/tasks.h:1541 [inline]
RIP: 0010:rcu_tasks_verify_work_fn+0x1b6/0x270 kernel/rcu/tasks.h:1553
Code: 80 3c 10 00 0f 85 b5 00 00 00 48 8b 35 5b 5a 77 0c b9 64 00 00 00 bf 08 00 00 00 48 c7 c2 a0 ca 99 9b e8 ad 6d e2 ff eb 97 90 <0f> 0b 90 eb 91 48 89 df e8 3d 8d 8f 00 e9 69 ff ff ff 48 89 df e8
RSP: 0000:ffffc90000067cd0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffff8edeb928 RCX: 0000000000000000
RDX: 1ffffffff1dbd725 RSI: ffffffff81e97b49 RDI: fffff5200000cf6d
RBP: 1ffff9200000cf9a R08: 0000000000000007 R09: 0000000000000000
R10: 8000000000000000 R11: 0000000000000001 R12: 0000000000000bb8
R13: 00000000ffffffff R14: 0000000000000001 R15: ffffffff8edeb928
FS: 0000000000000000(0000) GS:ffff888123c5c000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000000eb96000 CR4: 00000000003526f0
Call Trace:
<TASK>
rcu_tasks_verify_schedule_work+0x95/0xa0 kernel/rcu/tasks.h:1565
do_one_initcall+0x11c/0x6f0 init/main.c:1362
do_initcall_level init/main.c:1424 [inline]
do_initcalls init/main.c:1440 [inline]
do_basic_setup init/main.c:1460 [inline]
kernel_init_freeable+0x6ea/0x7b0 init/main.c:1675
kernel_init+0x21/0x1e0 init/main.c:1565
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
* Struck through repros no longer work on HEAD.