Hello, syzbot found the following issue on: HEAD commit: 2865ba82476a Merge git://git.kernel.org/pub/scm/linux/kern.. git tree: bpf console output: https://syzkaller.appspot.com/x/log.txt?x=10732da5300000 kernel config: https://syzkaller.appspot.com/x/.config?x=c31c0936547df9ea dashboard link: https://syzkaller.appspot.com/bug?extid=664b58e9a40fbb2cec71 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11834d43300000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=169a6273300000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+664b58e9a40fbb2cec71@xxxxxxxxxxxxxxxxxxxxxxxxx general protection fault, probably for non-canonical address 0xdffffc0000000024: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000120-0x0000000000000127] CPU: 0 PID: 8406 Comm: syz-executor074 Not tainted 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:cgroup_ancestor include/linux/cgroup.h:593 [inline] RIP: 0010:__bpf_sk_ancestor_cgroup_id net/core/filter.c:4494 [inline] RIP: 0010:____bpf_skb_ancestor_cgroup_id net/core/filter.c:4504 [inline] RIP: 0010:bpf_skb_ancestor_cgroup_id+0x152/0x300 net/core/filter.c:4501 Code: 03 80 3c 02 00 0f 85 9f 01 00 00 48 8b 9b 58 04 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bb 20 01 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 48 01 00 00 8b ab 20 01 00 00 RSP: 0018:ffffc9000101f828 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000024 RSI: ffffffff87291cee RDI: 0000000000000120 RBP: 0000000000000080 R08: 0000000000000000 R09: 0000000000000007 R10: ffffffff87291cd1 R11: 000000000000001f R12: fffffffffffffe00 R13: 00000000fffffe00 R14: ffffc9000101fc30 R15: ffffc90000e48048 FS: 0000000001234300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000200 CR3: 000000007193e000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: bpf_prog_dcdd7aeecda69f3f+0x54/0x690 bpf_dispatcher_nop_func include/linux/bpf.h:717 [inline] __bpf_prog_run include/linux/filter.h:624 [inline] bpf_prog_run include/linux/filter.h:631 [inline] bpf_test_run+0x381/0xa30 net/bpf/test_run.c:119 bpf_prog_test_run_skb+0xac5/0x1d20 net/bpf/test_run.c:657 bpf_prog_test_run kernel/bpf/syscall.c:3307 [inline] __sys_bpf+0x2137/0x5df0 kernel/bpf/syscall.c:4605 __do_sys_bpf kernel/bpf/syscall.c:4691 [inline] __se_sys_bpf kernel/bpf/syscall.c:4689 [inline] __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:4689 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x43f059 Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 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 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc82a88608 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 0000000000400488 RCX: 000000000043f059 RDX: 0000000000000040 RSI: 0000000020000280 RDI: 000000000000000a RBP: 0000000000403040 R08: 0000000000000000 R09: 0000000000400488 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004030d0 R13: 0000000000000000 R14: 00000000004ad018 R15: 0000000000400488 Modules linked in: ---[ end trace 55d65f18b4ef47bb ]--- RIP: 0010:cgroup_ancestor include/linux/cgroup.h:593 [inline] RIP: 0010:__bpf_sk_ancestor_cgroup_id net/core/filter.c:4494 [inline] RIP: 0010:____bpf_skb_ancestor_cgroup_id net/core/filter.c:4504 [inline] RIP: 0010:bpf_skb_ancestor_cgroup_id+0x152/0x300 net/core/filter.c:4501 Code: 03 80 3c 02 00 0f 85 9f 01 00 00 48 8b 9b 58 04 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bb 20 01 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 48 01 00 00 8b ab 20 01 00 00 RSP: 0018:ffffc9000101f828 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000024 RSI: ffffffff87291cee RDI: 0000000000000120 RBP: 0000000000000080 R08: 0000000000000000 R09: 0000000000000007 R10: ffffffff87291cd1 R11: 000000000000001f R12: fffffffffffffe00 R13: 00000000fffffe00 R14: ffffc9000101fc30 R15: ffffc90000e48048 FS: 0000000001234300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb37a158740 CR3: 000000007193e000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 03 80 3c 02 00 0f add 0xf00023c(%rax),%eax 6: 85 9f 01 00 00 48 test %ebx,0x48000001(%rdi) c: 8b 9b 58 04 00 00 mov 0x458(%rbx),%ebx 12: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 19: fc ff df 1c: 48 8d bb 20 01 00 00 lea 0x120(%rbx),%rdi 23: 48 89 fa mov %rdi,%rdx 26: 48 c1 ea 03 shr $0x3,%rdx * 2a: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction 2e: 84 c0 test %al,%al 30: 74 08 je 0x3a 32: 3c 03 cmp $0x3,%al 34: 0f 8e 48 01 00 00 jle 0x182 3a: 8b ab 20 01 00 00 mov 0x120(%rbx),%ebp --- 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. syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
