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KCSAN: data-race in sk_psock_drop / sk_psock_verdict_data_ready

Status: auto-obsoleted due to no activity on 2024/03/14 17:30
Subsystems: bpf net
[Documentation on labels]
Reported-by: syzbot+6be21fc4f7f96e879d85@syzkaller.appspotmail.com
First crash: 67d, last: 67d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in sk_psock_drop / sk_psock_verdict_data_ready

write to 0xffff8881385368b8 of 8 bytes by task 2949 on cpu 1:
 sk_psock_stop_verdict net/core/skmsg.c:1254 [inline]
 sk_psock_drop+0x138/0x1f0 net/core/skmsg.c:843
 sk_psock_put include/linux/skmsg.h:459 [inline]
 unix_bpf_recvmsg+0x610/0x720 net/unix/unix_bpf.c:90
 unix_dgram_recvmsg+0x63/0x90 net/unix/af_unix.c:2481
 sock_recvmsg_nosec net/socket.c:1046 [inline]
 sock_recvmsg net/socket.c:1068 [inline]
 ____sys_recvmsg+0x156/0x310 net/socket.c:2803
 ___sys_recvmsg net/socket.c:2845 [inline]
 do_recvmmsg+0x2eb/0x720 net/socket.c:2939
 __sys_recvmmsg net/socket.c:3018 [inline]
 __do_sys_recvmmsg net/socket.c:3041 [inline]
 __se_sys_recvmmsg net/socket.c:3034 [inline]
 __x64_sys_recvmmsg+0xe2/0x160 net/socket.c:3034
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881385368b8 of 8 bytes by task 2956 on cpu 0:
 sk_psock_verdict_data_ready+0xdb/0x1e0 net/core/skmsg.c:1230
 unix_dgram_sendmsg+0xd8b/0x1150 net/unix/af_unix.c:2112
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x37c/0x4d0 net/socket.c:2584
 ___sys_sendmsg net/socket.c:2638 [inline]
 __sys_sendmmsg+0x269/0x500 net/socket.c:2724
 __do_sys_sendmmsg net/socket.c:2753 [inline]
 __se_sys_sendmmsg net/socket.c:2750 [inline]
 __x64_sys_sendmmsg+0x57/0x60 net/socket.c:2750
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0xffffffff83b83520 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2956 Comm: syz-executor.2 Not tainted 6.8.0-rc3-syzkaller-00047-g047371968ffc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 13be30067 P4D 13be30067 PUD 13e4c4067 PMD 0 
Oops: 0010 [#1] PREEMPT SMP
CPU: 0 PID: 2956 Comm: syz-executor.2 Not tainted 6.8.0-rc3-syzkaller-00047-g047371968ffc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc90003eb7ab8 EFLAGS: 00010286
RAX: 44575b2a4ccb1500 RBX: 0000000000000004 RCX: ffffffff84c55499
RDX: 000000000000043e RSI: 0000000000000000 RDI: ffff888104546a80
RBP: ffff888138536800 R08: 0001ffff85c40e07 R09: 0000000000000200
R10: 0001ffffffffffff R11: ffff888138ffd140 R12: ffff888104546b68
R13: ffff888104546ae0 R14: ffff888104546a80 R15: 0000000000000001
FS:  00007f266d49a6c0(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000014a10e000 CR4: 00000000003506f0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 sk_psock_verdict_data_ready+0xe4/0x1e0 net/core/skmsg.c:1230
 unix_dgram_sendmsg+0xd8b/0x1150 net/unix/af_unix.c:2112
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x37c/0x4d0 net/socket.c:2584
 ___sys_sendmsg net/socket.c:2638 [inline]
 __sys_sendmmsg+0x269/0x500 net/socket.c:2724
 __do_sys_sendmmsg net/socket.c:2753 [inline]
 __se_sys_sendmmsg net/socket.c:2750 [inline]
 __x64_sys_sendmmsg+0x57/0x60 net/socket.c:2750
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f266e139da9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f266d49a0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f266e268050 RCX: 00007f266e139da9
RDX: 0000000000000001 RSI: 0000000020001680 RDI: 0000000000000006
RBP: 00007f266e18647a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007f266e268050 R15: 00007fff9e3a7e38
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc90003eb7ab8 EFLAGS: 00010286
RAX: 44575b2a4ccb1500 RBX: 0000000000000004 RCX: ffffffff84c55499
RDX: 000000000000043e RSI: 0000000000000000 RDI: ffff888104546a80
RBP: ffff888138536800 R08: 0001ffff85c40e07 R09: 0000000000000200
R10: 0001ffffffffffff R11: ffff888138ffd140 R12: ffff888104546b68
R13: ffff888104546ae0 R14: ffff888104546a80 R15: 0000000000000001
FS:  00007f266d49a6c0(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000014a10e000 CR4: 00000000003506f0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/02/08 17:29 upstream 047371968ffc 7f07e9b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in sk_psock_drop / sk_psock_verdict_data_ready
* Struck through repros no longer work on HEAD.