[syzbot ci] Re: bpf: Prep patches for static stack liveness.

[syzbot ci] Re: bpf: Prep patches for static stack liveness.

[syzbot ci]

syzbot ci has tested the following series

[v1] bpf: Prep patches for static stack liveness.
https://lore.kernel.org/all/20260401021635.34636-1-alexei.starovoitov@gmail.com
* [PATCH bpf-next 1/6] bpf: Do register range validation early
* [PATCH bpf-next 2/6] bpf: Sort subprogs in topological order after check_cfg()
* [PATCH bpf-next 3/6] selftests/bpf: Add tests for subprog topological ordering
* [PATCH bpf-next 4/6] bpf: Add compute_const_regs() and prune_dead_branches() passes
* [PATCH bpf-next 5/6] bpf: Move verifier helpers to header
* [PATCH bpf-next 6/6] bpf: Add helper and kfunc stack access size resolution

and found the following issue:
UBSAN: array-index-out-of-bounds in do_check

Full report is available here:
https://ci.syzbot.org/series/3bdef783-321d-4d8d-9fbb-fd61f6cd92d5

***

UBSAN: array-index-out-of-bounds in do_check

tree:      bpf-next
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf-next.git
base:      0eeb0094ba0321f0927806857b5f01c1577bc245
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/925251e6-c091-44e6-a321-22bd3bffd780/config

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
lec:lane_module_init: lec.c: initialized
mpoa:atm_mpoa_init: mpc.c: initialized
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_CAIF protocol family
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 2025.5 (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 (25300061146, 122105816)->(25454415888, -32248926)
registered taskstats version 1
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in kernel/bpf/verifier.c:21704:16
index 10 is out of range for type 'u32[10]' (aka 'unsigned int[10]')
CPU: 0 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
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 ubsan_epilogue+0xa/0x30
 __ubsan_handle_out_of_bounds+0xe8/0xf0
 do_check+0x77a1/0x11d50
 do_check_common+0x21ea/0x2dc0
 bpf_check+0x242f/0x1cd90
 bpf_prog_load+0x1484/0x1ae0
 __sys_bpf+0x618/0x950
 kern_sys_bpf+0x185/0x700
 load+0x488/0xad0
 do_one_initcall+0x250/0x8d0
 do_initcall_level+0x104/0x190
 do_initcalls+0x59/0xa0
 kernel_init_freeable+0x2a6/0x3e0
 kernel_init+0x1d/0x1d0
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30
 </TASK>
---[ end trace ]---


***

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: syzbot@syzkaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.

To test a patch for this bug, please reply with `#syz test`
(should be on a separate line).

The patch should be attached to the email.
Note: arguments like custom git repos and branches are not supported.

[syzbot ci] Re: bpf: Prep patches for static stack liveness.

[syzbot ci]

syzbot ci has tested the following series

[v2] bpf: Prep patches for static stack liveness.
https://lore.kernel.org/all/20260402061744.10885-1-alexei.starovoitov@gmail.com
* [PATCH v2 bpf-next 1/6] bpf: Do register range validation early
* [PATCH v2 bpf-next 2/6] bpf: Sort subprogs in topological order after check_cfg()
* [PATCH v2 bpf-next 3/6] selftests/bpf: Add tests for subprog topological ordering
* [PATCH v2 bpf-next 4/6] bpf: Add bpf_compute_const_regs() and bpf_prune_dead_branches() passes
* [PATCH v2 bpf-next 5/6] bpf: Move verifier helpers to header
* [PATCH v2 bpf-next 6/6] bpf: Add helper and kfunc stack access size resolution

and found the following issue:
UBSAN: array-index-out-of-bounds in do_check

Full report is available here:
https://ci.syzbot.org/series/472db170-a3e5-4e2f-992a-f066f3ec68a0

***

UBSAN: array-index-out-of-bounds in do_check

tree:      bpf-next
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf-next.git
base:      0eeb0094ba0321f0927806857b5f01c1577bc245
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/35679c0d-9085-497b-89c5-d447be366fc7/config

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
lec:lane_module_init: lec.c: initialized
mpoa:atm_mpoa_init: mpc.c: initialized
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_CAIF protocol family
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 2025.5 (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 (24350040289, 119535998)->(24496627492, -27051205)
registered taskstats version 1
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in kernel/bpf/verifier.c:21711:16
index 10 is out of range for type 'u32[10]' (aka 'unsigned int[10]')
CPU: 0 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
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 ubsan_epilogue+0xa/0x30
 __ubsan_handle_out_of_bounds+0xe8/0xf0
 do_check+0x77a1/0x11d50
 do_check_common+0x21ea/0x2dc0
 bpf_check+0x242f/0x1cd90
 bpf_prog_load+0x1484/0x1ae0
 __sys_bpf+0x618/0x950
 kern_sys_bpf+0x185/0x700
 load+0x488/0xad0
 do_one_initcall+0x250/0x8d0
 do_initcall_level+0x104/0x190
 do_initcalls+0x59/0xa0
 kernel_init_freeable+0x2a6/0x3e0
 kernel_init+0x1d/0x1d0
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30
 </TASK>
---[ end trace ]---


***

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: syzbot@syzkaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.

To test a patch for this bug, please reply with `#syz test`
(should be on a separate line).

The patch should be attached to the email.
Note: arguments like custom git repos and branches are not supported.

Re: [syzbot ci] Re: bpf: Prep patches for static stack liveness.

[Alexei Starovoitov]

On Thu, Apr 2, 2026 at 5:53 AM syzbot ci
<syzbot+ci5d1af9c009034c4e@syzkaller.appspotmail.com> wrote:
>
> ------------[ cut here ]------------
> UBSAN: array-index-out-of-bounds in kernel/bpf/verifier.c:21711:16
> index 10 is out of range for type 'u32[10]' (aka 'unsigned int[10]')

Yes, it's speculative out of bounds. r10 will not appear as const,
since loop that populates it goes to ARRAY_SIZE(aux->const_reg_vals);.

If that's the only thing I'll fix it up while applying.