[syzbot] general protection fault in bpf_skb_ancestor_cgroup_id

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syzbot

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Sep 17, 2021, 5:06:28 PM9/17/21
to and...@kernel.org, a...@kernel.org, b...@vger.kernel.org, dan...@iogearbox.net, da...@davemloft.net, ha...@kernel.org, john.fa...@gmail.com, ka...@fb.com, kps...@kernel.org, ku...@kernel.org, linux-...@vger.kernel.org, net...@vger.kernel.org, songliu...@fb.com, syzkall...@googlegroups.com, y...@fb.com
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+664b58...@syzkaller.appspotmail.com

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 syzk...@googlegroups.com.

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

syzbot

unread,
Sep 17, 2021, 7:08:11 PM9/17/21
to dan...@iogearbox.net, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+664b58...@syzkaller.appspotmail.com

Tested on:

commit: f9eec43b bpf, cgroup: test fix
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/dborkman/bpf.git pr/bpf-cgroup-test
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

Note: testing is done by a robot and is best-effort only.

syzbot

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Sep 20, 2021, 9:27:10 PM9/20/21
to dan...@iogearbox.net, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in bpf_skb_ancestor_cgroup_id

general protection fault, probably for non-canonical address 0xdffffc0000000024: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000120-0x0000000000000127]
CPU: 1 PID: 8926 Comm: syz-executor165 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:ffffc900024ff828 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000024 RSI: ffffffff87291e2e RDI: 0000000000000120
RBP: 0000000000000080 R08: 0000000000000000 R09: 0000000000000007
R10: ffffffff87291e11 R11: 000000000000001f R12: fffffffffffffe00
R13: 00000000fffffe00 R14: ffffc900024ffc30 R15: ffffc90000e5e048
FS: 0000555556f84300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000200 CR3: 000000007a257000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
bpf_prog_dcdd7aeecda69f3f+0x54/0xd28
bpf_dispatcher_nop_func include/linux/bpf.h:718 [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: 0033:0x7fe81439ad09
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:00007ffeaf4ba018 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe81439ad09
RDX: 0000000000000040 RSI: 0000000020000280 RDI: 000000000000000a
RBP: 00007fe81435eeb0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe81435ef40
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace e8b1d8fcff795ce6 ]---
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:ffffc900024ff828 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000024 RSI: ffffffff87291e2e RDI: 0000000000000120
RBP: 0000000000000080 R08: 0000000000000000 R09: 0000000000000007
R10: ffffffff87291e11 R11: 000000000000001f R12: fffffffffffffe00
R13: 00000000fffffe00 R14: ffffc900024ffc30 R15: ffffc90000e5e048
FS: 0000555556f84300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb1e3bc7388 CR3: 000000007a257000 CR4: 00000000001506e0
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


Tested on:

commit: 39f15afa bpf, cgroup: test fix 2
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/dborkman/bpf.git pr/bpf-cgroup-test2
console output: https://syzkaller.appspot.com/x/log.txt?x=1785691d300000

syzbot

unread,
Sep 21, 2021, 8:31:09 AM9/21/21
to dan...@iogearbox.net, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+664b58...@syzkaller.appspotmail.com

Tested on:

commit: 93f377ac bpf, test, cgroup: Use cgroup_sk_{alloc,free}..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/dborkman/bpf.git pr/bpf-cgroup-test3
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

syzbot

unread,
Sep 21, 2021, 4:04:16 PM9/21/21
to dan...@iogearbox.net, syzkall...@googlegroups.com

syzbot

unread,
Sep 23, 2021, 10:21:13 AM9/23/21
to dan...@iogearbox.net, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+664b58...@syzkaller.appspotmail.com

Tested on:

commit: 0a3ead8a bpf, test, cgroup: Use sk_{alloc,free} for te..
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/dborkman/bpf.git pr/bpf-cgroup-test4
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