On Sun, Aug 03, 2025 at 10:08:32PM -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: a6923c06a3b2 Merge tag 'bpf-fixes' of git://git.kernel.org.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1561dcf0580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f89bb9497754f485 > dashboard link: https://syzkaller.appspot.com/bug?extid=a9ed3d9132939852d0df > compiler: aarch64-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 > userspace arch: arm64 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=165d0aa2580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=117bd834580000 > > Downloadable assets: > disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/fa3fbcfdac58/non_bootable_disk-a6923c06.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/9862ca8219e0/vmlinux-a6923c06.xz > kernel image: https://storage.googleapis.com/syzbot-assets/042ebe320cfd/Image-a6923c06.gz.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+a9ed3d9132939852d0df@xxxxxxxxxxxxxxxxxxxxxxxxx > > ------------[ cut here ]------------ > verifier bug: not inlined functions bpf_probe_read_kernel_str#115 is missing func(1) > WARNING: CPU: 1 PID: 3594 at kernel/bpf/verifier.c:22838 do_misc_fixups+0x1784/0x1ab4 kernel/bpf/verifier.c:22838 > Modules linked in: > CPU: 1 UID: 0 PID: 3594 Comm: syz.2.17 Not tainted 6.16.0-syzkaller-11105-ga6923c06a3b2 #0 PREEMPT > Hardware name: linux,dummy-virt (DT) > pstate: 61402009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) > pc : do_misc_fixups+0x1784/0x1ab4 kernel/bpf/verifier.c:22838 > lr : do_misc_fixups+0x1784/0x1ab4 kernel/bpf/verifier.c:22838 > sp : ffff80008936b9a0 > x29: ffff80008936b9a0 x28: f5ff8000832f5000 x27: 000000000000000a > x26: f8f0000007ba8000 x25: 0000000000000000 x24: f8f0000007bae200 > x23: 000000000000f0ff x22: 000000000000000a x21: f8f0000007bae128 > x20: f8f0000007ba8aa8 x19: ffff80008243e828 x18: 0000000000000000 > x17: 0000000000000000 x16: 0000000000000000 x15: ffff800081b73b80 > x14: 0000000000000342 x13: 0000000000000000 x12: 0000000000000002 > x11: 00000000000000c0 x10: 646e0773d90f24cc x9 : 73727a981a23afd7 > x8 : fcf0000007bb36f8 x7 : 0000000000000190 x6 : 0000003978391654 > x5 : 0000000000000001 x4 : fbffff3fffffffff x3 : 000000000000ffff > x2 : 0000000000000000 x1 : 0000000000000000 x0 : fcf0000007bb2500 > Call trace: > do_misc_fixups+0x1784/0x1ab4 kernel/bpf/verifier.c:22838 (P) > bpf_check+0x1308/0x2a8c kernel/bpf/verifier.c:24739 > bpf_prog_load+0x634/0xb74 kernel/bpf/syscall.c:2979 > __sys_bpf+0x2e0/0x1a3c kernel/bpf/syscall.c:6029 > __do_sys_bpf kernel/bpf/syscall.c:6139 [inline] > __se_sys_bpf kernel/bpf/syscall.c:6137 [inline] > __arm64_sys_bpf+0x24/0x34 kernel/bpf/syscall.c:6137 > __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] > invoke_syscall+0x48/0x110 arch/arm64/kernel/syscall.c:49 > el0_svc_common.constprop.0+0x40/0xe0 arch/arm64/kernel/syscall.c:132 > do_el0_svc+0x1c/0x28 arch/arm64/kernel/syscall.c:151 > el0_svc+0x34/0x10c arch/arm64/kernel/entry-common.c:879 > el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:898 > el0t_64_sync+0x1a4/0x1a8 arch/arm64/kernel/entry.S:596 > ---[ end trace 0000000000000000 ]--- > > > --- > 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 trying suggested fix by Alexei jirka #syz test --- diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 0806295945e4..6aa303f76849 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -11344,6 +11344,13 @@ static bool can_elide_value_nullness(enum bpf_map_type type) } } +static bool is_valid_proto(const struct bpf_func_proto *fn, int func_id) +{ + if (func_id == BPF_FUNC_tail_call) + return true; + return fn && fn->func; +} + static int get_helper_proto(struct bpf_verifier_env *env, int func_id, const struct bpf_func_proto **ptr) { @@ -11354,7 +11361,7 @@ static int get_helper_proto(struct bpf_verifier_env *env, int func_id, return -EINVAL; *ptr = env->ops->get_func_proto(func_id, env->prog); - return *ptr ? 0 : -EINVAL; + return is_valid_proto(*ptr, func_id) ? 0 : -EINVAL; } static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
