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KCSAN: data-race in __ip6_datagram_connect / rawv6_sendmsg (3)

Status: auto-obsoleted due to no activity on 2025/12/06 14:52
Subsystems: net
[Documentation on labels]
First crash: 179d, last: 112d
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __ip6_datagram_connect / rawv6_sendmsg (2) net 6 1 2057d 2057d 0/29 closed as invalid on 2020/06/18 14:13
upstream KCSAN: data-race in __ip6_datagram_connect / rawv6_sendmsg net 6 1 2273d 2273d 0/29 auto-closed as invalid on 2020/01/20 16:26

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __ip6_datagram_connect / rawv6_sendmsg

write to 0xffff8881035bddb8 of 16 bytes by task 13805 on cpu 0:
 __ip6_datagram_connect+0x6d1/0x7e0 net/ipv6/datagram.c:246
 ip6_datagram_connect net/ipv6/datagram.c:279 [inline]
 ip6_datagram_connect_v6_only+0x52/0x80 net/ipv6/datagram.c:291
 inet_dgram_connect+0x125/0x1c0 net/ipv4/af_inet.c:594
 __sys_connect_file net/socket.c:2102 [inline]
 __sys_connect+0x1ef/0x2b0 net/socket.c:2121
 __do_sys_connect net/socket.c:2127 [inline]
 __se_sys_connect net/socket.c:2124 [inline]
 __x64_sys_connect+0x3f/0x50 net/socket.c:2124
 x64_sys_call+0x2c0c/0x3000 arch/x86/include/generated/asm/syscalls_64.h:43
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881035bddb8 of 16 bytes by task 13807 on cpu 1:
 rawv6_sendmsg+0x8ac/0xf70 net/ipv6/raw.c:874
 inet_sendmsg+0xc2/0xd0 net/ipv4/af_inet.c:853
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x102/0x180 net/socket.c:742
 ____sys_sendmsg+0x345/0x4e0 net/socket.c:2630
 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2684
 __sys_sendmmsg+0x178/0x300 net/socket.c:2773
 __do_sys_sendmmsg net/socket.c:2800 [inline]
 __se_sys_sendmmsg net/socket.c:2797 [inline]
 __x64_sys_sendmmsg+0x57/0x70 net/socket.c:2797
 x64_sys_call+0x1c4a/0x3000 arch/x86/include/generated/asm/syscalls_64.h:308
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 13807 Comm: syz.6.3169 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/11 14:46 upstream 0739473694c4 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __ip6_datagram_connect / rawv6_sendmsg
2025/09/23 02:39 upstream cec1e6e5d1ab 0ac7291c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __ip6_datagram_connect / rawv6_sendmsg
2025/08/04 21:53 upstream d632ab86aff2 f5bcc8dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __ip6_datagram_connect / rawv6_sendmsg
* Struck through repros no longer work on HEAD.