kernel BUG in sock_write_iter

Status: premoderation: reported C repro on 2026/09/09 22:48
Reported-by: syzbot+566896fdf0e6e6e68444@syzkaller.appspotmail.com
First crash: 20h24m, last: 20h24m

Sample crash report:
------------[ cut here ]------------
kernel BUG at net/socket.c:715!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 0 UID: 0 PID: 313 Comm: syz-executor389 Not tainted syzkaller #0 01d0fef691542fecbcfb5551c0a705324fcaa78c
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:sock_sendmsg_nosec net/socket.c:715 [inline]
RIP: 0010:__sock_sendmsg net/socket.c:727 [inline]
RIP: 0010:sock_write_iter+0x44f/0x490 net/socket.c:1148
Code: 4c 89 f7 4c 89 ee 48 89 da 4d 89 fb 41 ba c3 1c 74 ce 45 03 53 f1 74 02 0f 0b 2e e8 e7 f7 88 1b e9 a5 fe ff ff e8 c1 ca 0e fd <0f> 0b e8 ba ca 0e fd 49 83 c6 18 4d 89 f5 49 c1 ee 03 43 80 3c 3e
RSP: 0018:ffffc900011ffb60 EFLAGS: 00010293
RAX: ffffffff8478ac9f RBX: 00000000fffffdef RCX: ffff8881063a3900
RDX: 0000000000000000 RSI: 00000000fffffdef RDI: 00000000fffffdef
RBP: ffffc900011ffc90 R08: ffffc900011ff7c7 R09: 1ffff9200023fef8
R10: dffffc0000000000 R11: fffff5200023fef9 R12: 1ffff9200023ff70
R13: ffffc900011ffba0 R14: ffff888121db3480 R15: dffffc0000000000
FS:  00005555717e53c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000463390 CR3: 0000000105b2c000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x762/0xfd0 fs/read_write.c:684
 ksys_write+0x145/0x260 fs/read_write.c:737
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x7f/0x90 fs/read_write.c:746
 x64_sys_call+0x271c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fdc223bbcb9
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd47bc1738 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007fdc223bbcb9
RDX: 0000000000000001 RSI: 0000200000000000 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd47bc1878
R13: 0000000000000002 R14: 00002000000000c0 R15: 0000000000000002
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:sock_sendmsg_nosec net/socket.c:715 [inline]
RIP: 0010:__sock_sendmsg net/socket.c:727 [inline]
RIP: 0010:sock_write_iter+0x44f/0x490 net/socket.c:1148
Code: 4c 89 f7 4c 89 ee 48 89 da 4d 89 fb 41 ba c3 1c 74 ce 45 03 53 f1 74 02 0f 0b 2e e8 e7 f7 88 1b e9 a5 fe ff ff e8 c1 ca 0e fd <0f> 0b e8 ba ca 0e fd 49 83 c6 18 4d 89 f5 49 c1 ee 03 43 80 3c 3e
RSP: 0018:ffffc900011ffb60 EFLAGS: 00010293
RAX: ffffffff8478ac9f RBX: 00000000fffffdef RCX: ffff8881063a3900
RDX: 0000000000000000 RSI: 00000000fffffdef RDI: 00000000fffffdef
RBP: ffffc900011ffc90 R08: ffffc900011ff7c7 R09: 1ffff9200023fef8
R10: dffffc0000000000 R11: fffff5200023fef9 R12: 1ffff9200023ff70
R13: ffffc900011ffba0 R14: ffff888121db3480 R15: dffffc0000000000
FS:  00005555717e53c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000463390 CR3: 0000000105b2c000 CR4: 00000000003526b0

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/09 22:47 android16-6.12 89698cd757af 4e8b1cc6 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust kernel BUG in sock_write_iter
* Struck through repros no longer work on HEAD.