kernel BUG in sock_write_iter

Status: upstream: reported C repro on 2026/09/18 05:26
Bug presence: origin:lts
[Documentation on labels]
Reported-by: syzbot+8ec7866cec4f09ba1d9e@syzkaller.appspotmail.com
First crash: 48d, last: 27d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2026/10/16 lts (merge base) 2a5f794b8be1 C [report] kernel BUG in sock_write_iter
2026/10/16 upstream (ToT) 70dd4ee72eb2 C Didn't crash
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-12 kernel BUG in sock_write_iter origin:lts -1 syz, C 2 25d 56d 0/1 premoderation: reported C repro on 2026/09/09 22:48
android-5-10 kernel BUG in sock_write_iter -1 syz, C 1 34d 34d 0/2 upstream: reported C repro on 2026/10/01 20:45
android-6-1 kernel BUG in sock_write_iter -1 syz, C 5 18d 52d 0/2 upstream: reported C repro on 2026/09/13 18:43

Sample crash report:
------------[ cut here ]------------
kernel BUG at net/socket.c:707!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 303 Comm: syz-executor412 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:sock_sendmsg_nosec net/socket.c:707 [inline]
RIP: 0010:__sock_sendmsg net/socket.c:716 [inline]
RIP: 0010:sock_write_iter+0x39d/0x3a0 net/socket.c:1080
Code: f0 fd e9 98 fe ff ff 44 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c 34 fe ff ff 4c 89 ef e8 5d 29 f0 fd e9 27 fe ff ff e8 d3 a8 b0 fd <0f> 0b 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 38 48 89
RSP: 0018:ffffc90000997b60 EFLAGS: 00010293
RAX: ffffffff83b9328d RBX: 00000000fffffdef RCX: ffff88810b8c1400
RDX: 0000000000000000 RSI: 00000000fffffdef RDI: 00000000fffffdef
RBP: ffffc90000997c70 R08: ffffc900009977c7 R09: 1ffff92000132ef8
R10: dffffc0000000000 R11: fffff52000132ef9 R12: dffffc0000000000
R13: ffff88812218fc20 R14: ffffc90000997ba0 R15: 1ffff92000132f70
FS:  000055557b4683c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000463390 CR3: 00000001266b5000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 call_write_iter include/linux/fs.h:2218 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x831/0xfd0 fs/read_write.c:594
 ksys_write+0x14a/0x260 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:656
 x64_sys_call+0x8ef/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fab9e5dccb9
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:00007fffc7abfed8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007fab9e5dccb9
RDX: 0000000000000001 RSI: 0000200000000000 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fffc7ac0018
R13: 0000000000000002 R14: 00002000000000c0 R15: 0000000000000002
 </TASK>
Modules linked in:
---[ end trace 26092019529ce166 ]---
RIP: 0010:sock_sendmsg_nosec net/socket.c:707 [inline]
RIP: 0010:__sock_sendmsg net/socket.c:716 [inline]
RIP: 0010:sock_write_iter+0x39d/0x3a0 net/socket.c:1080
Code: f0 fd e9 98 fe ff ff 44 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c 34 fe ff ff 4c 89 ef e8 5d 29 f0 fd e9 27 fe ff ff e8 d3 a8 b0 fd <0f> 0b 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 38 48 89
RSP: 0018:ffffc90000997b60 EFLAGS: 00010293
RAX: ffffffff83b9328d RBX: 00000000fffffdef RCX: ffff88810b8c1400
RDX: 0000000000000000 RSI: 00000000fffffdef RDI: 00000000fffffdef
RBP: ffffc90000997c70 R08: ffffc900009977c7 R09: 1ffff92000132ef8
R10: dffffc0000000000 R11: fffff52000132ef9 R12: dffffc0000000000
R13: ffff88812218fc20 R14: ffffc90000997ba0 R15: 1ffff92000132f70
FS:  000055557b4683c0(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000463390 CR3: 00000001266b5000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/08 15:26 android13-5.15-lts d6c8aee048e0 4f6a9fcf .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-5-15 kernel BUG in sock_write_iter
2026/09/18 05:25 android13-5.15-lts 5bfe2b8c1439 8d7d05f1 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-5-15 kernel BUG in sock_write_iter
* Struck through repros no longer work on HEAD.