Hello, syzbot found the following issue on: HEAD commit: 0b58e108042b Add linux-next specific files for 20240703 git tree: linux-next console+strace: https://syzkaller.appspot.com/x/log.txt?x=17a85c9e980000 kernel config: https://syzkaller.appspot.com/x/.config?x=ed034204f2e40e53 dashboard link: https://syzkaller.appspot.com/bug?extid=6fc359860535c8a466fa compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14aca369980000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11a6f6e1980000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/1d079762feae/disk-0b58e108.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/e53996c8d8c2/vmlinux-0b58e108.xz kernel image: https://storage.googleapis.com/syzbot-assets/a0bf21cdd844/bzImage-0b58e108.xz The issue was bisected to: commit 401cb7dae8130fd34eb84648e02ab4c506df7d5e Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Date: Thu Jun 20 13:22:04 2024 +0000 net: Reference bpf_redirect_info via task_struct on PREEMPT_RT. bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16373059980000 final oops: https://syzkaller.appspot.com/x/report.txt?x=15373059980000 console output: https://syzkaller.appspot.com/x/log.txt?x=11373059980000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+6fc359860535c8a466fa@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.") Oops: stack segment: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 0 UID: 0 PID: 5103 Comm: syz-executor681 Not tainted 6.10.0-rc6-next-20240703-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 RIP: 0010:bpf_net_ctx_get_ri include/linux/filter.h:788 [inline] RIP: 0010:__bpf_xdp_redirect_map include/linux/filter.h:1699 [inline] RIP: 0010:cpu_map_redirect+0x5c/0x470 kernel/bpf/cpumap.c:643 Code: 81 c3 00 18 00 00 48 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 48 89 df e8 62 6b 3d 00 4c 8b 2b 49 8d 5d 38 48 89 dd 48 c1 ed 03 <42> 0f b6 44 35 00 84 c0 0f 85 fd 02 00 00 44 8b 33 44 89 f6 83 e6 RSP: 0018:ffffc9000395f960 EFLAGS: 00010202 RAX: 1ffff110051dd300 RBX: 0000000000000038 RCX: ffff888028ee8000 RDX: 0000000000000000 RSI: 000000000395f9b0 RDI: ffff88802ec3fc00 RBP: 0000000000000007 R08: 0000000000000007 R09: ffffffff81b5ee2f R10: 0000000000000004 R11: ffff888028ee8000 R12: 000000000395f9b0 R13: 0000000000000000 R14: dffffc0000000000 R15: ffff88802ec3fc00 FS: 000055556a17a380(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000099d4b98 CR3: 0000000021f40000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> bpf_prog_ec9efaa32d58ce69+0x56/0x5a __bpf_prog_run include/linux/filter.h:691 [inline] bpf_prog_run_xdp include/net/xdp.h:514 [inline] tun_build_skb drivers/net/tun.c:1711 [inline] tun_get_user+0x3321/0x4560 drivers/net/tun.c:1819 tun_chr_write_iter+0x113/0x1f0 drivers/net/tun.c:2048 new_sync_write fs/read_write.c:497 [inline] vfs_write+0xa72/0xc90 fs/read_write.c:590 ksys_write+0x1a0/0x2c0 fs/read_write.c:643 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f40ef4f8070 Code: 40 00 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 80 3d 51 e0 07 00 00 74 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 48 83 ec 28 48 89 RSP: 002b:00007ffcf4c50d48 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f40ef4f8070 RDX: 0000000000000022 RSI: 0000000020000a40 RDI: 00000000000000c8 RBP: 0000000000000000 R08: 00007ffc0000000d R09: 00007ffc0000000d R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:bpf_net_ctx_get_ri include/linux/filter.h:788 [inline] RIP: 0010:__bpf_xdp_redirect_map include/linux/filter.h:1699 [inline] RIP: 0010:cpu_map_redirect+0x5c/0x470 kernel/bpf/cpumap.c:643 Code: 81 c3 00 18 00 00 48 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 48 89 df e8 62 6b 3d 00 4c 8b 2b 49 8d 5d 38 48 89 dd 48 c1 ed 03 <42> 0f b6 44 35 00 84 c0 0f 85 fd 02 00 00 44 8b 33 44 89 f6 83 e6 RSP: 0018:ffffc9000395f960 EFLAGS: 00010202 RAX: 1ffff110051dd300 RBX: 0000000000000038 RCX: ffff888028ee8000 RDX: 0000000000000000 RSI: 000000000395f9b0 RDI: ffff88802ec3fc00 RBP: 0000000000000007 R08: 0000000000000007 R09: ffffffff81b5ee2f R10: 0000000000000004 R11: ffff888028ee8000 R12: 000000000395f9b0 R13: 0000000000000000 R14: dffffc0000000000 R15: ffff88802ec3fc00 FS: 000055556a17a380(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000099d4b98 CR3: 0000000021f40000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 81 c3 00 18 00 00 add $0x1800,%ebx 6: 48 89 d8 mov %rbx,%rax 9: 48 c1 e8 03 shr $0x3,%rax d: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1) 12: 74 08 je 0x1c 14: 48 89 df mov %rbx,%rdi 17: e8 62 6b 3d 00 call 0x3d6b7e 1c: 4c 8b 2b mov (%rbx),%r13 1f: 49 8d 5d 38 lea 0x38(%r13),%rbx 23: 48 89 dd mov %rbx,%rbp 26: 48 c1 ed 03 shr $0x3,%rbp * 2a: 42 0f b6 44 35 00 movzbl 0x0(%rbp,%r14,1),%eax <-- trapping instruction 30: 84 c0 test %al,%al 32: 0f 85 fd 02 00 00 jne 0x335 38: 44 8b 33 mov (%rbx),%r14d 3b: 44 89 f6 mov %r14d,%esi 3e: 83 .byte 0x83 3f: e6 .byte 0xe6 --- 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. For information about bisection process see: https://goo.gl/tpsmEJ#bisection 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
