net/bpf/test_run.c | 9 +++++++++ 1 file changed, 9 insertions(+)
From: Feng Yang <yangfeng@kylinos.cn>
The bpf_lwt_xmit_push_encap helper needs to access skb_dst(skb)->dev to
calculate the needed headroom:
err = skb_cow_head(skb,
len + LL_RESERVED_SPACE(skb_dst(skb)->dev));
But skb->_skb_refdst may not be initialized when the skb is set up by
bpf_prog_test_run_skb function. Executing bpf_lwt_push_ip_encap function
in this scenario will trigger null pointer dereference, causing a kernel
crash as Yinhao reported:
[ 105.186365] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 105.186382] #PF: supervisor read access in kernel mode
[ 105.186388] #PF: error_code(0x0000) - not-present page
[ 105.186393] PGD 121d3d067 P4D 121d3d067 PUD 106c83067 PMD 0
[ 105.186404] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 105.186412] CPU: 3 PID: 3250 Comm: poc Kdump: loaded Not tainted 6.19.0-rc5 #1
[ 105.186423] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 105.186427] RIP: 0010:bpf_lwt_push_ip_encap+0x1eb/0x520
[ 105.186443] Code: 0f 84 de 01 00 00 0f b7 4a 04 66 85 c9 0f 85 47 01 00 00 31 c0 5b 5d 41 5c 41 5d 41 5e c3 cc cc cc cc 48 8b 73 58 48 83 e6 fe <48> 8b 36 0f b7 be ec 00 00 00 0f b7 b6 e6 00 00 00 01 fe 83 e6 f0
[ 105.186449] RSP: 0018:ffffbb0e0387bc50 EFLAGS: 00010246
[ 105.186455] RAX: 000000000000004e RBX: ffff94c74e036500 RCX: ffff94c74874da00
[ 105.186460] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff94c74e036500
[ 105.186463] RBP: 0000000000000001 R08: 0000000000000002 R09: 0000000000000000
[ 105.186467] R10: ffffbb0e0387bd50 R11: 0000000000000000 R12: ffffbb0e0387bc98
[ 105.186471] R13: 0000000000000014 R14: 0000000000000000 R15: 0000000000000002
[ 105.186484] FS: 00007f166aa4d680(0000) GS:ffff94c8b7780000(0000) knlGS:0000000000000000
[ 105.186490] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 105.186494] CR2: 0000000000000000 CR3: 000000015eade001 CR4: 0000000000770ee0
[ 105.186499] PKRU: 55555554
[ 105.186502] Call Trace:
[ 105.186507] <TASK>
[ 105.186513] bpf_lwt_xmit_push_encap+0x2b/0x40
[ 105.186522] bpf_prog_a75eaad51e517912+0x41/0x49
[ 105.186536] ? kvm_clock_get_cycles+0x18/0x30
[ 105.186547] ? ktime_get+0x3c/0xa0
[ 105.186554] bpf_test_run+0x195/0x320
[ 105.186563] ? bpf_test_run+0x10f/0x320
[ 105.186579] bpf_prog_test_run_skb+0x2f5/0x4f0
[ 105.186590] __sys_bpf+0x69c/0xa40
[ 105.186603] __x64_sys_bpf+0x1e/0x30
[ 105.186611] do_syscall_64+0x59/0x110
[ 105.186620] entry_SYSCALL_64_after_hwframe+0x76/0xe0
[ 105.186649] RIP: 0033:0x7f166a97455d
Temporarily add the setting of skb->_skb_refdst before bpf_test_run to resolve the issue.
Fixes: 52f278774e79 ("bpf: implement BPF_LWT_ENCAP_IP mode in bpf_lwt_push_encap")
Reported-by: Yinhao Hu <dddddd@hust.edu.cn>
Reported-by: Kaiyan Mei <M202472210@hust.edu.cn>
Closes: https://groups.google.com/g/hust-os-kernel-patches/c/8-a0kPpBW2s
Signed-off-by: Yun Lu <luyun@kylinos.cn>
Signed-off-by: Feng Yang <yangfeng@kylinos.cn>
Tested-by: syzbot@syzkaller.appspotmail.com
---
Changes in v4:
- add rcu lock
- Link to v3: https://lore.kernel.org/all/20260206055113.63476-1-yangfeng59949@163.com/
Changes in v3:
- use dst_init
- Link to v2: https://lore.kernel.org/all/20260205092227.126665-1-yangfeng59949@163.com/
Changes in v2:
- Link to v1: https://lore.kernel.org/all/20260127084520.13890-1-luyun_611@163.com/
---
net/bpf/test_run.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 178c4738e63b..79b60ab9e682 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -989,6 +989,7 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
u32 tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
struct net *net = current->nsproxy->net_ns;
struct net_device *dev = net->loopback_dev;
+ struct dst_entry bpf_test_run_lwt_xmit_dst;
u32 headroom = NET_SKB_PAD + NET_IP_ALIGN;
u32 linear_sz = kattr->test.data_size_in;
u32 repeat = kattr->test.repeat;
@@ -1156,6 +1157,14 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
skb->ip_summed = CHECKSUM_COMPLETE;
}
+ if (prog->type == BPF_PROG_TYPE_LWT_XMIT) {
+ dst_init(&bpf_test_run_lwt_xmit_dst, NULL, NULL,
+ DST_OBSOLETE_NONE, DST_NOCOUNT);
+ bpf_test_run_lwt_xmit_dst.dev = dev;
+ rcu_read_lock();
+ skb_dst_set_noref(skb, &bpf_test_run_lwt_xmit_dst);
+ rcu_read_unlock();
+ }
ret = bpf_test_run(prog, skb, repeat, &retval, &duration, false);
if (ret)
goto out;
--
2.43.0syzbot ci has tested the following series [v4] bpf: test_run: Fix the null pointer dereference issue in bpf_lwt_xmit_push_encap https://lore.kernel.org/all/20260209015111.28144-1-yangfeng59949@163.com * [PATCH v4] bpf: test_run: Fix the null pointer dereference issue in bpf_lwt_xmit_push_encap and found the following issues: * general protection fault in ip6_tnl_xmit * general protection fault in tnl_update_pmtu * general protection fault in wg_xmit * general protection fault in xfrm_lookup_with_ifid Full report is available here: https://ci.syzbot.org/series/af38a4c5-943d-44d2-91e6-299e4e0a94db *** general protection fault in ip6_tnl_xmit tree: bpf-next URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf-next.git base: db975debcb8c4cd367a78811bc1ba84c83f854bd arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/c4ef1868-7d17-40c4-b5a7-b2d7bec3a6fe/config C repro: https://ci.syzbot.org/findings/311bc7a0-3bf0-490c-b561-a21f38f4d8e9/c_repro syz repro: https://ci.syzbot.org/findings/311bc7a0-3bf0-490c-b561-a21f38f4d8e9/syz_repro Oops: general protection fault, probably for non-canonical address 0xdffffc000000000d: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f] CPU: 1 UID: 0 PID: 5991 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:dst_neigh_lookup include/net/dst.h:404 [inline] RIP: 0010:ip6_tnl_xmit+0x14a1/0x2af0 net/ipv6/ip6_tunnel.c:1123 Code: 74 12 4c 89 ef e8 af d8 ea f7 48 ba 00 00 00 00 00 fc ff df 4d 01 f4 49 83 c4 18 4d 8b 6d 00 49 83 c5 68 4c 89 e8 48 c1 e8 03 <80> 3c 10 00 74 08 4c 89 ef e8 81 d8 ea f7 4d 8b 5d 00 4c 89 ff 31 RSP: 0018:ffffc90003976e60 EFLAGS: 00010202 RAX: 000000000000000d RBX: 1ffff1102e6c7d07 RCX: ffff88810b2c57c0 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90003977028 R08: ffff88810b2c57c0 R09: 0000000000000002 R10: 000000000000dd86 R11: 0000000000000000 R12: ffff88816a0ce066 R13: 0000000000000068 R14: ffff88816a0ce000 R15: ffffc90003977ba0 FS: 000055555f394500(0000) GS:ffff8882a9927000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30263fff CR3: 000000010d832000 CR4: 00000000000006f0 Call Trace: <TASK> ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1400 [inline] ip6_tnl_start_xmit+0xc79/0x11d0 net/ipv6/ip6_tunnel.c:1448 __netdev_start_xmit include/linux/netdevice.h:5273 [inline] netdev_start_xmit include/linux/netdevice.h:5282 [inline] xmit_one net/core/dev.c:3853 [inline] dev_hard_start_xmit+0x2cd/0x7f0 net/core/dev.c:3869 __dev_queue_xmit+0x14dd/0x32a0 net/core/dev.c:4819 dev_queue_xmit include/linux/netdevice.h:3381 [inline] __bpf_tx_skb+0x18e/0x260 net/core/filter.c:2153 ____bpf_clone_redirect net/core/filter.c:2487 [inline] bpf_clone_redirect+0x313/0x4b0 net/core/filter.c:2450 bpf_prog_2f59963de350c2d2+0x5e/0x67 bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] bpf_test_run+0x354/0x830 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x13b4/0x1e00 net/bpf/test_run.c:1168 bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4721 __sys_bpf+0x643/0x950 kernel/bpf/syscall.c:6246 __do_sys_bpf kernel/bpf/syscall.c:6341 [inline] __se_sys_bpf kernel/bpf/syscall.c:6339 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6339 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff39439acb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffc03f9fef8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007ff394615fa0 RCX: 00007ff39439acb9 RDX: 0000000000000028 RSI: 00002000000000c0 RDI: 000000000000000a RBP: 00007ff394408bf7 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff394615fac R14: 00007ff394615fa0 R15: 00007ff394615fa0 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:dst_neigh_lookup include/net/dst.h:404 [inline] RIP: 0010:ip6_tnl_xmit+0x14a1/0x2af0 net/ipv6/ip6_tunnel.c:1123 Code: 74 12 4c 89 ef e8 af d8 ea f7 48 ba 00 00 00 00 00 fc ff df 4d 01 f4 49 83 c4 18 4d 8b 6d 00 49 83 c5 68 4c 89 e8 48 c1 e8 03 <80> 3c 10 00 74 08 4c 89 ef e8 81 d8 ea f7 4d 8b 5d 00 4c 89 ff 31 RSP: 0018:ffffc90003976e60 EFLAGS: 00010202 RAX: 000000000000000d RBX: 1ffff1102e6c7d07 RCX: ffff88810b2c57c0 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90003977028 R08: ffff88810b2c57c0 R09: 0000000000000002 R10: 000000000000dd86 R11: 0000000000000000 R12: ffff88816a0ce066 R13: 0000000000000068 R14: ffff88816a0ce000 R15: ffffc90003977ba0 FS: 000055555f394500(0000) GS:ffff8882a9927000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30263fff CR3: 000000010d832000 CR4: 00000000000006f0 ---------------- Code disassembly (best guess): 0: 74 12 je 0x14 2: 4c 89 ef mov %r13,%rdi 5: e8 af d8 ea f7 call 0xf7ead8b9 a: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx 11: fc ff df 14: 4d 01 f4 add %r14,%r12 17: 49 83 c4 18 add $0x18,%r12 1b: 4d 8b 6d 00 mov 0x0(%r13),%r13 1f: 49 83 c5 68 add $0x68,%r13 23: 4c 89 e8 mov %r13,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 80 3c 10 00 cmpb $0x0,(%rax,%rdx,1) <-- trapping instruction 2e: 74 08 je 0x38 30: 4c 89 ef mov %r13,%rdi 33: e8 81 d8 ea f7 call 0xf7ead8b9 38: 4d 8b 5d 00 mov 0x0(%r13),%r11 3c: 4c 89 ff mov %r15,%rdi 3f: 31 .byte 0x31 *** general protection fault in tnl_update_pmtu tree: bpf-next URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf-next.git base: db975debcb8c4cd367a78811bc1ba84c83f854bd arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/c4ef1868-7d17-40c4-b5a7-b2d7bec3a6fe/config C repro: https://ci.syzbot.org/findings/78a52206-e4f0-4a95-a881-32bbaab25810/c_repro syz repro: https://ci.syzbot.org/findings/78a52206-e4f0-4a95-a881-32bbaab25810/syz_repro Oops: general protection fault, probably for non-canonical address 0xdffffc000000000a: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000050-0x0000000000000057] CPU: 0 UID: 0 PID: 5980 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:skb_dst_update_pmtu_no_confirm include/net/dst.h:565 [inline] RIP: 0010:tnl_update_pmtu+0x52b/0x1190 net/ipv4/ip_tunnel.c:533 Code: c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 ad 38 2a f8 4c 8b 3b 49 83 c7 50 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ff e8 87 38 2a f8 4d 8b 3f 4d 85 ff 8b 5c RSP: 0018:ffffc90003d56e28 EFLAGS: 00010206 RAX: 000000000000000a RBX: ffffc90003d57ba8 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: ffffc90003d57ba0 RDI: 0000000000000000 RBP: ffffc90003d57ba0 R08: ffffffff89db4393 R09: ffffffff8e35a3a0 R10: ffffc90003d56de0 R11: fffff520007aadbe R12: ffff88816a305380 R13: ffff88816a3053d8 R14: 1ffff1102d460a7b R15: 0000000000000050 FS: 000055559418b500(0000) GS:ffff88818e327000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30863fff CR3: 00000001bea06000 CR4: 00000000000006f0 Call Trace: <TASK> ip_tunnel_xmit+0xd36/0x2430 net/ipv4/ip_tunnel.c:805 __gre_xmit net/ipv4/ip_gre.c:490 [inline] ipgre_xmit+0x8e6/0xc60 net/ipv4/ip_gre.c:694 __netdev_start_xmit include/linux/netdevice.h:5273 [inline] netdev_start_xmit include/linux/netdevice.h:5282 [inline] xmit_one net/core/dev.c:3853 [inline] dev_hard_start_xmit+0x2cd/0x7f0 net/core/dev.c:3869 __dev_queue_xmit+0x14dd/0x32a0 net/core/dev.c:4819 dev_queue_xmit include/linux/netdevice.h:3381 [inline] __bpf_tx_skb+0x18e/0x260 net/core/filter.c:2153 ____bpf_clone_redirect net/core/filter.c:2487 [inline] bpf_clone_redirect+0x313/0x4b0 net/core/filter.c:2450 bpf_prog_7c64685fc60f7d44+0x5f/0x68 bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] bpf_test_run+0x354/0x830 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x13b4/0x1e00 net/bpf/test_run.c:1168 bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4721 __sys_bpf+0x643/0x950 kernel/bpf/syscall.c:6246 __do_sys_bpf kernel/bpf/syscall.c:6341 [inline] __se_sys_bpf kernel/bpf/syscall.c:6339 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6339 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6668d9acb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffcdef544a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f6669015fa0 RCX: 00007f6668d9acb9 RDX: 000000000000002c RSI: 0000200000000080 RDI: 000000000000000a RBP: 00007f6668e08bf7 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6669015fac R14: 00007f6669015fa0 R15: 00007f6669015fa0 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:skb_dst_update_pmtu_no_confirm include/net/dst.h:565 [inline] RIP: 0010:tnl_update_pmtu+0x52b/0x1190 net/ipv4/ip_tunnel.c:533 Code: c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 ad 38 2a f8 4c 8b 3b 49 83 c7 50 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ff e8 87 38 2a f8 4d 8b 3f 4d 85 ff 8b 5c RSP: 0018:ffffc90003d56e28 EFLAGS: 00010206 RAX: 000000000000000a RBX: ffffc90003d57ba8 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: ffffc90003d57ba0 RDI: 0000000000000000 RBP: ffffc90003d57ba0 R08: ffffffff89db4393 R09: ffffffff8e35a3a0 R10: ffffc90003d56de0 R11: fffff520007aadbe R12: ffff88816a305380 R13: ffff88816a3053d8 R14: 1ffff1102d460a7b R15: 0000000000000050 FS: 000055559418b500(0000) GS:ffff88818e327000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30863fff CR3: 00000001bea06000 CR4: 00000000000006f0 ---------------- Code disassembly (best guess): 0: c1 e8 03 shr $0x3,%eax 3: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) 8: 74 08 je 0x12 a: 48 89 df mov %rbx,%rdi d: e8 ad 38 2a f8 call 0xf82a38bf 12: 4c 8b 3b mov (%rbx),%r15 15: 49 83 c7 50 add $0x50,%r15 19: 4c 89 f8 mov %r15,%rax 1c: 48 c1 e8 03 shr $0x3,%rax 20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 27: fc ff df * 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction 2e: 74 08 je 0x38 30: 4c 89 ff mov %r15,%rdi 33: e8 87 38 2a f8 call 0xf82a38bf 38: 4d 8b 3f mov (%r15),%r15 3b: 4d 85 ff test %r15,%r15 3e: 8b .byte 0x8b 3f: 5c pop %rsp *** general protection fault in wg_xmit tree: bpf-next URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf-next.git base: db975debcb8c4cd367a78811bc1ba84c83f854bd arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/c4ef1868-7d17-40c4-b5a7-b2d7bec3a6fe/config C repro: https://ci.syzbot.org/findings/9650e699-cf43-4d3b-841d-ae1a23f976f0/c_repro syz repro: https://ci.syzbot.org/findings/9650e699-cf43-4d3b-841d-ae1a23f976f0/syz_repro Oops: general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] CPU: 0 UID: 0 PID: 5985 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:dst_mtu include/net/dst.h:219 [inline] RIP: 0010:wg_xmit+0x355/0xf70 drivers/net/wireguard/device.c:173 Code: 00 fc ff df 80 3c 08 00 74 08 4c 89 ff e8 83 84 d9 fb 4d 8b 3f 49 83 c7 20 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ff e8 5d 84 d9 fb 4d 8b 3f 49 81 ff e0 38 RSP: 0018:ffffc90003cc7060 EFLAGS: 00010202 RAX: 0000000000000004 RBX: ffffc90003cc7ba0 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90003cc7190 R08: ffffffff8fced577 R09: 1ffffffff1f9daae R10: dffffc0000000000 R11: fffffbfff1f9daaf R12: ffffc90003cc70c0 R13: 1ffff1102ebe283b R14: ffff888175f14180 R15: 0000000000000020 FS: 00005555734f8500(0000) GS:ffff88818e327000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30663fff CR3: 00000001704ae000 CR4: 00000000000006f0 Call Trace: <TASK> __netdev_start_xmit include/linux/netdevice.h:5273 [inline] netdev_start_xmit include/linux/netdevice.h:5282 [inline] xmit_one net/core/dev.c:3853 [inline] dev_hard_start_xmit+0x2cd/0x7f0 net/core/dev.c:3869 __dev_queue_xmit+0x14dd/0x32a0 net/core/dev.c:4819 dev_queue_xmit include/linux/netdevice.h:3381 [inline] __bpf_tx_skb+0x18e/0x260 net/core/filter.c:2153 ____bpf_clone_redirect net/core/filter.c:2487 [inline] bpf_clone_redirect+0x313/0x4b0 net/core/filter.c:2450 bpf_prog_bd919e7baf24f63c+0x5f/0x68 bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] bpf_test_run+0x354/0x830 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x13b4/0x1e00 net/bpf/test_run.c:1168 bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4721 __sys_bpf+0x643/0x950 kernel/bpf/syscall.c:6246 __do_sys_bpf kernel/bpf/syscall.c:6341 [inline] __se_sys_bpf kernel/bpf/syscall.c:6339 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6339 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc57899acb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd806bfbf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fc578c15fa0 RCX: 00007fc57899acb9 RDX: 0000000000000050 RSI: 0000200000000080 RDI: 000000000000000a RBP: 00007fc578a08bf7 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc578c15fac R14: 00007fc578c15fa0 R15: 00007fc578c15fa0 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:dst_mtu include/net/dst.h:219 [inline] RIP: 0010:wg_xmit+0x355/0xf70 drivers/net/wireguard/device.c:173 Code: 00 fc ff df 80 3c 08 00 74 08 4c 89 ff e8 83 84 d9 fb 4d 8b 3f 49 83 c7 20 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 4c 89 ff e8 5d 84 d9 fb 4d 8b 3f 49 81 ff e0 38 RSP: 0018:ffffc90003cc7060 EFLAGS: 00010202 RAX: 0000000000000004 RBX: ffffc90003cc7ba0 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90003cc7190 R08: ffffffff8fced577 R09: 1ffffffff1f9daae R10: dffffc0000000000 R11: fffffbfff1f9daaf R12: ffffc90003cc70c0 R13: 1ffff1102ebe283b R14: ffff888175f14180 R15: 0000000000000020 FS: 00005555734f8500(0000) GS:ffff88818e327000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30663fff CR3: 00000001704ae000 CR4: 00000000000006f0 ---------------- Code disassembly (best guess), 3 bytes skipped: 0: df 80 3c 08 00 74 filds 0x7400083c(%rax) 6: 08 4c 89 ff or %cl,-0x1(%rcx,%rcx,4) a: e8 83 84 d9 fb call 0xfbd98492 f: 4d 8b 3f mov (%r15),%r15 12: 49 83 c7 20 add $0x20,%r15 16: 4c 89 f8 mov %r15,%rax 19: 48 c1 e8 03 shr $0x3,%rax 1d: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx 24: fc ff df * 27: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction 2b: 74 08 je 0x35 2d: 4c 89 ff mov %r15,%rdi 30: e8 5d 84 d9 fb call 0xfbd98492 35: 4d 8b 3f mov (%r15),%r15 38: 49 rex.WB 39: 81 .byte 0x81 3a: ff e0 jmp *%rax 3c: 38 .byte 0x38 *** general protection fault in xfrm_lookup_with_ifid tree: bpf-next URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf-next.git base: db975debcb8c4cd367a78811bc1ba84c83f854bd arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/c4ef1868-7d17-40c4-b5a7-b2d7bec3a6fe/config C repro: https://ci.syzbot.org/findings/2ae3c5a4-d593-4385-8e69-f77a40c2382d/c_repro syz repro: https://ci.syzbot.org/findings/2ae3c5a4-d593-4385-8e69-f77a40c2382d/syz_repro Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 UID: 0 PID: 5978 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:xfrm_lookup_with_ifid+0xe1/0x1af0 net/xfrm/xfrm_policy.c:3181 Code: 24 20 4d 8d 66 08 4c 89 e0 48 c1 e8 03 4d 89 ee 42 80 3c 28 00 74 08 4c 89 e7 e8 5a 1f 17 f8 4d 8b 24 24 4c 89 e0 48 c1 e8 03 <42> 0f b6 04 30 84 c0 0f 85 94 17 00 00 41 0f b7 04 24 89 44 24 28 RSP: 0018:ffffc900045f6ea0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffc900045f6f40 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900045f6f50 RBP: ffffc900045f6fb8 R08: ffffc900045f6f4f R09: 0000000000000000 R10: ffffc900045f6f40 R11: fffff520008bedea R12: 0000000000000000 R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000000000 FS: 00005555873db500(0000) GS:ffff88818e327000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2fa63fff CR3: 000000016e128000 CR4: 00000000000006f0 Call Trace: <TASK> xfrm_lookup net/xfrm/xfrm_policy.c:3336 [inline] xfrm_lookup_route+0x3c/0x1c0 net/xfrm/xfrm_policy.c:3347 vti_xmit net/ipv4/ip_vti.c:217 [inline] vti_tunnel_xmit+0x48e/0x18f0 net/ipv4/ip_vti.c:307 __netdev_start_xmit include/linux/netdevice.h:5273 [inline] netdev_start_xmit include/linux/netdevice.h:5282 [inline] xmit_one net/core/dev.c:3853 [inline] dev_hard_start_xmit+0x2cd/0x7f0 net/core/dev.c:3869 __dev_queue_xmit+0x14dd/0x32a0 net/core/dev.c:4819 dev_queue_xmit include/linux/netdevice.h:3381 [inline] __bpf_tx_skb+0x18e/0x260 net/core/filter.c:2153 ____bpf_clone_redirect net/core/filter.c:2487 [inline] bpf_clone_redirect+0x313/0x4b0 net/core/filter.c:2450 bpf_prog_e16758452f539c38+0x5f/0x68 bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] bpf_test_run+0x354/0x830 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x13b4/0x1e00 net/bpf/test_run.c:1168 bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4721 __sys_bpf+0x643/0x950 kernel/bpf/syscall.c:6246 __do_sys_bpf kernel/bpf/syscall.c:6341 [inline] __se_sys_bpf kernel/bpf/syscall.c:6339 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6339 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f722f59acb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff2a77bfd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f722f815fa0 RCX: 00007f722f59acb9 RDX: 000000000000002c RSI: 0000200000000080 RDI: 000000000000000a RBP: 00007f722f608bf7 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f722f815fac R14: 00007f722f815fa0 R15: 00007f722f815fa0 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:xfrm_lookup_with_ifid+0xe1/0x1af0 net/xfrm/xfrm_policy.c:3181 Code: 24 20 4d 8d 66 08 4c 89 e0 48 c1 e8 03 4d 89 ee 42 80 3c 28 00 74 08 4c 89 e7 e8 5a 1f 17 f8 4d 8b 24 24 4c 89 e0 48 c1 e8 03 <42> 0f b6 04 30 84 c0 0f 85 94 17 00 00 41 0f b7 04 24 89 44 24 28 RSP: 0018:ffffc900045f6ea0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffc900045f6f40 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900045f6f50 RBP: ffffc900045f6fb8 R08: ffffc900045f6f4f R09: 0000000000000000 R10: ffffc900045f6f40 R11: fffff520008bedea R12: 0000000000000000 R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000000000 FS: 00005555873db500(0000) GS:ffff88818e327000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2fa63fff CR3: 000000016e128000 CR4: 00000000000006f0 ---------------- Code disassembly (best guess): 0: 24 20 and $0x20,%al 2: 4d 8d 66 08 lea 0x8(%r14),%r12 6: 4c 89 e0 mov %r12,%rax 9: 48 c1 e8 03 shr $0x3,%rax d: 4d 89 ee mov %r13,%r14 10: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) 15: 74 08 je 0x1f 17: 4c 89 e7 mov %r12,%rdi 1a: e8 5a 1f 17 f8 call 0xf8171f79 1f: 4d 8b 24 24 mov (%r12),%r12 23: 4c 89 e0 mov %r12,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 0f b6 04 30 movzbl (%rax,%r14,1),%eax <-- trapping instruction 2f: 84 c0 test %al,%al 31: 0f 85 94 17 00 00 jne 0x17cb 37: 41 0f b7 04 24 movzwl (%r12),%eax 3c: 89 44 24 28 mov %eax,0x28(%rsp) *** If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com --- This report is generated by a bot. It may contain errors. syzbot ci engineers can be reached at syzkaller@googlegroups.com.
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