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KCSAN: data-race in unix_maybe_add_creds / unix_release_sock

Status: auto-obsoleted due to no activity on 2025/10/14 01:49
Subsystems: net
[Documentation on labels]
First crash: 162d, last: 162d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in unix_maybe_add_creds / unix_release_sock

write to 0xffff888103568a20 of 8 bytes by task 12610 on cpu 0:
 sk_set_socket include/net/sock.h:2058 [inline]
 sock_orphan include/net/sock.h:2077 [inline]
 unix_release_sock+0x21f/0x790 net/unix/af_unix.c:678
 unix_release+0x58/0x80 net/unix/af_unix.c:1196
 __sock_release net/socket.c:649 [inline]
 sock_close+0x6b/0x150 net/socket.c:1439
 __fput+0x298/0x650 fs/file_table.c:468
 ____fput+0x1c/0x30 fs/file_table.c:496
 task_work_run+0x12e/0x1a0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xe4/0x100 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888103568a20 of 8 bytes by task 12602 on cpu 1:
 unix_maybe_add_creds+0x196/0x1e0 net/unix/af_unix.c:2046
 unix_dgram_sendmsg+0x629/0xfe0 net/unix/af_unix.c:2194
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x142/0x180 net/socket.c:729
 sock_write_iter+0x165/0x1b0 net/socket.c:1179
 io_write+0x60f/0xd40 io_uring/rw.c:1160
 __io_issue_sqe+0xfe/0x2e0 io_uring/io_uring.c:1773
 io_issue_sqe+0x53/0x970 io_uring/io_uring.c:1796
 io_queue_sqe io_uring/io_uring.c:2025 [inline]
 io_submit_sqe io_uring/io_uring.c:2284 [inline]
 io_submit_sqes+0x664/0x1050 io_uring/io_uring.c:2397
 __do_sys_io_uring_enter io_uring/io_uring.c:3464 [inline]
 __se_sys_io_uring_enter+0x1c1/0x1b70 io_uring/io_uring.c:3398
 __x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3398
 x64_sys_call+0x2de1/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:427
 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

value changed: 0xffff888106fc7400 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 12602 Comm: syz.3.3381 Not tainted 6.17.0-rc2-syzkaller-00028-gbe48bcf004f9 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/19 01:48 upstream be48bcf004f9 523f460e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in unix_maybe_add_creds / unix_release_sock
* Struck through repros no longer work on HEAD.