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KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock

Status: upstream: reported syz repro on 2025/03/31 20:23
Subsystems: rdma s390 net
[Documentation on labels]
Reported-by: syzbot+827ae2bfb3a3529333e9@syzkaller.appspotmail.com
First crash: 159d, last: 4d06h
Cause bisection: failed (error log, bisect log)
  
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[syzbot] Monthly rdma report (Apr 2025) 0 (1) 2025/04/03 07:06
[syzbot] [rdma?] [s390?] [net?] KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock 0 (1) 2025/03/31 20:23
▶ ▼ Last patch testing requests (4)
Created Duration User Patch Repo Result
2025/01/22 18:40 26m edumazet@google.com upstream OK log
2024/12/17 17:57 25m edumazet@google.com upstream report log
2024/11/18 12:17 26m retest repro upstream report log
2024/11/18 12:17 41m retest repro upstream report log
▶ ▼ Cause bisection attempts (2)
Created Duration User Patch Repo Result
2024/11/23 03:09 12h03m bisect upstream error job log
2024/10/30 07:33 13h41m bisect upstream error job log
marked invalid by edumazet@google.com

Sample crash report:
TCP: request_sock_TCP: Possible SYN flooding on port [::]:20002. Sending cookies.
TCP: request_sock_TCP: Possible SYN flooding on port [::]:20002. Sending cookies.
==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: null-ptr-deref in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
BUG: KASAN: null-ptr-deref in smc_tcp_syn_recv_sock+0xa7/0x4b0 net/smc/af_smc.c:131
Read of size 4 at addr 00000000000009d4 by task syz.4.10809/28966

CPU: 1 UID: 0 PID: 28966 Comm: syz.4.10809 Not tainted 6.12.0-rc4-syzkaller-00261-g850925a8133c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline]
 smc_tcp_syn_recv_sock+0xa7/0x4b0 net/smc/af_smc.c:131
 tcp_get_cookie_sock+0xd5/0x790 net/ipv4/syncookies.c:204
 cookie_v4_check+0xcf8/0x1d40 net/ipv4/syncookies.c:485
 tcp_v4_cookie_check net/ipv4/tcp_ipv4.c:1864 [inline]
 tcp_v4_do_rcv+0x98e/0xa90 net/ipv4/tcp_ipv4.c:1923
 tcp_v4_rcv+0x3cd2/0x4390 net/ipv4/tcp_ipv4.c:2340
 ip_protocol_deliver_rcu+0xba/0x4c0 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x316/0x570 net/ipv4/ip_input.c:233
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 ip_local_deliver+0x18e/0x1f0 net/ipv4/ip_input.c:254
 dst_input include/net/dst.h:460 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:449 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 ip_rcv+0x2c3/0x5d0 net/ipv4/ip_input.c:569
 __netif_receive_skb_one_core+0x199/0x1e0 net/core/dev.c:5666
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5779
 process_backlog+0x443/0x15f0 net/core/dev.c:6111
 __napi_poll.constprop.0+0xba/0x550 net/core/dev.c:6775
 napi_poll net/core/dev.c:6844 [inline]
 net_rx_action+0xa92/0x1010 net/core/dev.c:6966
 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
 do_softirq kernel/softirq.c:455 [inline]
 do_softirq+0xb2/0xf0 kernel/softirq.c:442
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:382
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]
 __dev_queue_xmit+0x887/0x4350 net/core/dev.c:4455
 dev_queue_xmit include/linux/netdevice.h:3094 [inline]
 neigh_hh_output include/net/neighbour.h:526 [inline]
 neigh_output include/net/neighbour.h:540 [inline]
 ip_finish_output2+0x16d7/0x2530 net/ipv4/ip_output.c:236
 __ip_finish_output net/ipv4/ip_output.c:314 [inline]
 __ip_finish_output+0x49e/0x950 net/ipv4/ip_output.c:296
 ip_finish_output+0x31/0x310 net/ipv4/ip_output.c:324
 NF_HOOK_COND include/linux/netfilter.h:303 [inline]
 ip_output+0x13b/0x2a0 net/ipv4/ip_output.c:434
 dst_output include/net/dst.h:450 [inline]
 ip_local_out+0x33e/0x4a0 net/ipv4/ip_output.c:130
 __ip_queue_xmit+0x747/0x1940 net/ipv4/ip_output.c:536
 __tcp_transmit_skb+0x2a4c/0x3dc0 net/ipv4/tcp_output.c:1466
 __tcp_send_ack.part.0+0x390/0x720 net/ipv4/tcp_output.c:4268
 __tcp_send_ack net/ipv4/tcp_output.c:4274 [inline]
 tcp_send_ack+0x82/0xa0 net/ipv4/tcp_output.c:4274
 tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6576 [inline]
 tcp_rcv_state_process+0x4332/0x4f30 net/ipv4/tcp_input.c:6770
 tcp_v4_do_rcv+0x1ad/0xa90 net/ipv4/tcp_ipv4.c:1938
 sk_backlog_rcv include/net/sock.h:1115 [inline]
 __release_sock+0x31b/0x400 net/core/sock.c:3072
 release_sock+0x5a/0x220 net/core/sock.c:3626
 mptcp_connect+0xc14/0xee0 net/mptcp/protocol.c:3800
 __inet_stream_connect+0x3ca/0x1020 net/ipv4/af_inet.c:679
 inet_stream_connect+0x57/0xa0 net/ipv4/af_inet.c:750
 __sys_connect_file+0x150/0x190 net/socket.c:2071
 __sys_connect+0x147/0x180 net/socket.c:2088
 __do_sys_connect net/socket.c:2098 [inline]
 __se_sys_connect net/socket.c:2095 [inline]
 __x64_sys_connect+0x72/0xb0 net/socket.c:2095
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f68acb7e719
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f68ada08038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f68acd35f80 RCX: 00007f68acb7e719
RDX: 0000000000000010 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007f68acbf132e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f68acd35f80 R15: 00007ffdea14cb48
 </TASK>
==================================================================
Oops: general protection fault, probably for non-canonical address 0xdffffc000000013a: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x00000000000009d0-0x00000000000009d7]
CPU: 1 UID: 0 PID: 28966 Comm: syz.4.10809 Tainted: G    B              6.12.0-rc4-syzkaller-00261-g850925a8133c #0
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline]
RIP: 0010:smc_tcp_syn_recv_sock+0xb8/0x4b0 net/smc/af_smc.c:131
Code: ad d4 09 00 00 be 04 00 00 00 44 8b bb 1c 04 00 00 4c 89 ef e8 69 94 2e f7 4c 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 14 02 4c 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 34
RSP: 0018:ffffc90000a18668 EFLAGS: 00010217
RAX: dffffc0000000000 RBX: ffff88805b9cb600 RCX: ffffffff814e856f
RDX: 000000000000013a RSI: ffffffff81ee031e RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 6e696c6261736944 R12: ffff88807df5bd00
R13: 00000000000009d4 R14: ffffc90000a186e8 R15: 0000000000000000
FS:  00007f68ada086c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f68ad9e7d58 CR3: 000000005e3fa000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 tcp_get_cookie_sock+0xd5/0x790 net/ipv4/syncookies.c:204
 cookie_v4_check+0xcf8/0x1d40 net/ipv4/syncookies.c:485
 tcp_v4_cookie_check net/ipv4/tcp_ipv4.c:1864 [inline]
 tcp_v4_do_rcv+0x98e/0xa90 net/ipv4/tcp_ipv4.c:1923
 tcp_v4_rcv+0x3cd2/0x4390 net/ipv4/tcp_ipv4.c:2340
 ip_protocol_deliver_rcu+0xba/0x4c0 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x316/0x570 net/ipv4/ip_input.c:233
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 ip_local_deliver+0x18e/0x1f0 net/ipv4/ip_input.c:254
 dst_input include/net/dst.h:460 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:449 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 ip_rcv+0x2c3/0x5d0 net/ipv4/ip_input.c:569
 __netif_receive_skb_one_core+0x199/0x1e0 net/core/dev.c:5666
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5779
 process_backlog+0x443/0x15f0 net/core/dev.c:6111
 __napi_poll.constprop.0+0xba/0x550 net/core/dev.c:6775
 napi_poll net/core/dev.c:6844 [inline]
 net_rx_action+0xa92/0x1010 net/core/dev.c:6966
 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
 do_softirq kernel/softirq.c:455 [inline]
 do_softirq+0xb2/0xf0 kernel/softirq.c:442
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:382
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]
 __dev_queue_xmit+0x887/0x4350 net/core/dev.c:4455
 dev_queue_xmit include/linux/netdevice.h:3094 [inline]
 neigh_hh_output include/net/neighbour.h:526 [inline]
 neigh_output include/net/neighbour.h:540 [inline]
 ip_finish_output2+0x16d7/0x2530 net/ipv4/ip_output.c:236
 __ip_finish_output net/ipv4/ip_output.c:314 [inline]
 __ip_finish_output+0x49e/0x950 net/ipv4/ip_output.c:296
 ip_finish_output+0x31/0x310 net/ipv4/ip_output.c:324
 NF_HOOK_COND include/linux/netfilter.h:303 [inline]
 ip_output+0x13b/0x2a0 net/ipv4/ip_output.c:434
 dst_output include/net/dst.h:450 [inline]
 ip_local_out+0x33e/0x4a0 net/ipv4/ip_output.c:130
 __ip_queue_xmit+0x747/0x1940 net/ipv4/ip_output.c:536
 __tcp_transmit_skb+0x2a4c/0x3dc0 net/ipv4/tcp_output.c:1466
 __tcp_send_ack.part.0+0x390/0x720 net/ipv4/tcp_output.c:4268
 __tcp_send_ack net/ipv4/tcp_output.c:4274 [inline]
 tcp_send_ack+0x82/0xa0 net/ipv4/tcp_output.c:4274
 tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6576 [inline]
 tcp_rcv_state_process+0x4332/0x4f30 net/ipv4/tcp_input.c:6770
 tcp_v4_do_rcv+0x1ad/0xa90 net/ipv4/tcp_ipv4.c:1938
 sk_backlog_rcv include/net/sock.h:1115 [inline]
 __release_sock+0x31b/0x400 net/core/sock.c:3072
 release_sock+0x5a/0x220 net/core/sock.c:3626
 mptcp_connect+0xc14/0xee0 net/mptcp/protocol.c:3800
 __inet_stream_connect+0x3ca/0x1020 net/ipv4/af_inet.c:679
 inet_stream_connect+0x57/0xa0 net/ipv4/af_inet.c:750
 __sys_connect_file+0x150/0x190 net/socket.c:2071
 __sys_connect+0x147/0x180 net/socket.c:2088
 __do_sys_connect net/socket.c:2098 [inline]
 __se_sys_connect net/socket.c:2095 [inline]
 __x64_sys_connect+0x72/0xb0 net/socket.c:2095
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f68acb7e719
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f68ada08038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f68acd35f80 RCX: 00007f68acb7e719
RDX: 0000000000000010 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007f68acbf132e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f68acd35f80 R15: 00007ffdea14cb48
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline]
RIP: 0010:smc_tcp_syn_recv_sock+0xb8/0x4b0 net/smc/af_smc.c:131
Code: ad d4 09 00 00 be 04 00 00 00 44 8b bb 1c 04 00 00 4c 89 ef e8 69 94 2e f7 4c 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 14 02 4c 89 e8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 34
RSP: 0018:ffffc90000a18668 EFLAGS: 00010217
RAX: dffffc0000000000 RBX: ffff88805b9cb600 RCX: ffffffff814e856f
RDX: 000000000000013a RSI: ffffffff81ee031e RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 6e696c6261736944 R12: ffff88807df5bd00
R13: 00000000000009d4 R14: ffffc90000a186e8 R15: 0000000000000000
FS:  00007f68ada086c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f68ad9e7d58 CR3: 000000005e3fa000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	09 00                	or     %eax,(%rax)
   2:	00 be 04 00 00 00    	add    %bh,0x4(%rsi)
   8:	44 8b bb 1c 04 00 00 	mov    0x41c(%rbx),%r15d
   f:	4c 89 ef             	mov    %r13,%rdi
  12:	e8 69 94 2e f7       	call   0xf72e9480
  17:	4c 89 ea             	mov    %r13,%rdx
  1a:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  21:	fc ff df
  24:	48 c1 ea 03          	shr    $0x3,%rdx
* 28:	0f b6 14 02          	movzbl (%rdx,%rax,1),%edx <-- trapping instruction
  2c:	4c 89 e8             	mov    %r13,%rax
  2f:	83 e0 07             	and    $0x7,%eax
  32:	83 c0 03             	add    $0x3,%eax
  35:	38 d0                	cmp    %dl,%al
  37:	7c 08                	jl     0x41
  39:	84 d2                	test   %dl,%dl
  3b:	0f                   	.byte 0xf
  3c:	85                   	.byte 0x85
  3d:	34                   	.byte 0x34

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/27 00:57 upstream 850925a8133c 65e8686b .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
2025/03/07 07:09 upstream 0f52fd4f67c6 831e3629 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
2025/02/24 10:07 upstream d082ecbc71e9 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
2025/02/23 03:10 upstream 5cf80612d3f7 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
2025/02/09 13:49 upstream 9946eaf552b1 ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
2024/11/04 09:13 upstream b9021de3ec2f f00eed24 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
2024/11/03 22:51 upstream b9021de3ec2f f00eed24 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
2024/10/25 10:01 upstream ae90f6a6170d c79b8ca5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
2025/01/26 08:43 upstream aa22f4da2a46 9fbd772e .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
2025/01/11 12:23 upstream 77a903cd8e5a 6dbc6a9b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
2025/03/30 02:07 upstream 7d06015d936c d3999433 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
2024/11/22 09:50 linux-next cfba9f07a1d6 4b25d554 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
2025/03/16 05:12 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci a5618886fdab e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: null-ptr-deref Read in smc_tcp_syn_recv_sock
* Struck through repros no longer work on HEAD.