Hello, syzbot found the following issue on: HEAD commit: 1c66f4a3612c bpf: Fix state use-after-free on push_stack().. git tree: bpf-next console+strace: https://syzkaller.appspot.com/x/log.txt?x=1346ed70580000 kernel config: https://syzkaller.appspot.com/x/.config?x=73696606574e3967 dashboard link: https://syzkaller.appspot.com/bug?extid=a36aac327960ff474804 compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1392610c580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11a9ee0c580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/2ddb1df1c757/disk-1c66f4a3.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/6a318fc92af0/vmlinux-1c66f4a3.xz kernel image: https://storage.googleapis.com/syzbot-assets/76c58dddcb6c/bzImage-1c66f4a3.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+a36aac327960ff474804@xxxxxxxxxxxxxxxxxxxxxxxxx ------------[ cut here ]------------ verifier bug: add backedge: no SCC in verification path, insn_idx 9(1) WARNING: CPU: 1 PID: 5838 at kernel/bpf/verifier.c:1970 add_scc_backedge kernel/bpf/verifier.c:1969 [inline] WARNING: CPU: 1 PID: 5838 at kernel/bpf/verifier.c:1970 is_state_visited kernel/bpf/verifier.c:19417 [inline] WARNING: CPU: 1 PID: 5838 at kernel/bpf/verifier.c:1970 do_check+0xda21/0xdba0 kernel/bpf/verifier.c:19861 Modules linked in: CPU: 1 UID: 0 PID: 5838 Comm: syz-executor286 Not tainted 6.15.0-syzkaller-g1c66f4a3612c #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:add_scc_backedge kernel/bpf/verifier.c:1969 [inline] RIP: 0010:is_state_visited kernel/bpf/verifier.c:19417 [inline] RIP: 0010:do_check+0xda21/0xdba0 kernel/bpf/verifier.c:19861 Code: 01 90 48 b8 00 00 00 00 00 fc ff df 41 0f b6 04 06 84 c0 0f 85 2b 01 00 00 41 8b 75 00 48 c7 c7 20 49 91 8b e8 d0 05 ad ff 90 <0f> 0b 90 90 e9 27 fe ff ff e8 11 5d e9 ff e8 3c 10 4d 00 ba 38 00 RSP: 0018:ffffc900043eeec0 EFLAGS: 00010246 RAX: 53f7659fb2f02200 RBX: ffffc900043ef180 RCX: ffff8880257d1e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002 RBP: ffffc900043ef2c8 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffffbfff1bfaa44 R12: ffff88801c7a4b00 R13: ffff88801c7a4b54 R14: 1ffff110038f496a R15: 0000000000000000 FS: 000055556bd6a380(0000) GS:ffff888125d54000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000ebea398 CR3: 00000000713fa000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> do_check_common+0x18fa/0x2460 kernel/bpf/verifier.c:23086 do_check_main kernel/bpf/verifier.c:23177 [inline] bpf_check+0x110e2/0x1a240 kernel/bpf/verifier.c:24530 bpf_prog_load+0x1318/0x1930 kernel/bpf/syscall.c:2972 __sys_bpf+0x5f1/0x860 kernel/bpf/syscall.c:5978 __do_sys_bpf kernel/bpf/syscall.c:6085 [inline] __se_sys_bpf kernel/bpf/syscall.c:6083 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6083 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f37a741f569 Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe3011bf08 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007ffe3011c0d8 RCX: 00007f37a741f569 RDX: 0000000000000094 RSI: 0000200000000840 RDI: 0000000000000005 RBP: 00007f37a7492610 R08: 00007ffe3011c0d8 R09: 00007ffe3011c0d8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffe3011c0c8 R14: 0000000000000001 R15: 0000000000000001 </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 syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. 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
