Hello, syzbot found the following issue on: HEAD commit: a33b5a08cbbd Merge tag 'sched_ext-for-6.15-rc3-fixes' of g.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1058f26f980000 kernel config: https://syzkaller.appspot.com/x/.config?x=85dd0f8b81b9d41f dashboard link: https://syzkaller.appspot.com/bug?extid=81fdaf0f522d5c5e41fb compiler: Debian clang version 15.0.6, Debian LLD 15.0.6 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/718e6f7bde0a/disk-a33b5a08.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/20f5e402fb15/vmlinux-a33b5a08.xz kernel image: https://storage.googleapis.com/syzbot-assets/2dd06e277fc7/bzImage-a33b5a08.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+81fdaf0f522d5c5e41fb@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KCSAN: data-race in choose_mountpoint_rcu / umount_tree write to 0xffff888108512d98 of 8 bytes by task 21705 on cpu 1: unhash_mnt fs/namespace.c:1050 [inline] umount_mnt fs/namespace.c:1064 [inline] umount_tree+0x6f0/0xb10 fs/namespace.c:1922 do_umount fs/namespace.c:-1 [inline] path_umount+0x9c1/0xa40 fs/namespace.c:2144 ksys_umount fs/namespace.c:2167 [inline] __do_sys_umount fs/namespace.c:2172 [inline] __se_sys_umount fs/namespace.c:2170 [inline] __x64_sys_umount+0xb7/0xe0 fs/namespace.c:2170 x64_sys_call+0x2883/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:167 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0x1a0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff888108512d98 of 8 bytes by task 21704 on cpu 0: choose_mountpoint_rcu+0x3d/0x130 fs/namei.c:1386 follow_dotdot_rcu fs/namei.c:2020 [inline] handle_dots+0x559/0x790 fs/namei.c:2095 walk_component fs/namei.c:2132 [inline] link_path_walk+0x5f6/0x840 fs/namei.c:2503 path_lookupat+0x6c/0x2a0 fs/namei.c:2659 filename_lookup+0x14b/0x340 fs/namei.c:2689 filename_setxattr+0x59/0x2b0 fs/xattr.c:660 path_setxattrat+0x28a/0x320 fs/xattr.c:713 __do_sys_setxattr fs/xattr.c:747 [inline] __se_sys_setxattr fs/xattr.c:743 [inline] __x64_sys_setxattr+0x6e/0x90 fs/xattr.c:743 x64_sys_call+0x28e7/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:189 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc9/0x1a0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0xffff888116147cc0 -> 0xffff8881065c23c0 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 21704 Comm: syz.6.5865 Not tainted 6.15.0-rc3-syzkaller-00008-ga33b5a08cbbd #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
