syzbot

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BUG: KCSAN: data-race in path_noexec / propagate_one

write to 0xffff88812b07fd30 of 4 bytes by task 32378 on cpu 0:
 propagate_one+0x32d/0x400 fs/pnode.c:267
 propagate_mnt+0x2f8/0x640 fs/pnode.c:319
 attach_recursive_mnt+0x519/0x1210 fs/namespace.c:2129
 graft_tree fs/namespace.c:2237 [inline]
 do_add_mount fs/namespace.c:2784 [inline]
 do_new_mount_fc fs/namespace.c:2823 [inline]
 do_new_mount fs/namespace.c:2877 [inline]
 path_mount+0x1b49/0x1c70 fs/namespace.c:3192
 do_mount fs/namespace.c:3205 [inline]
 __do_sys_mount fs/namespace.c:3413 [inline]
 __se_sys_mount+0x126/0x180 fs/namespace.c:3390
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3390
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812b07fd30 of 4 bytes by task 32380 on cpu 1:
 path_noexec+0x1e/0x70 fs/exec.c:111
 do_mmap+0x8b8/0xc90 mm/mmap.c:1494
 vm_mmap_pgoff+0xe5/0x170 mm/util.c:506
 ksys_mmap_pgoff+0x2a8/0x380 mm/mmap.c:1596
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 32380 Comm: modprobe Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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