==================================================================
BUG: KCSAN: data-race in file_remove_privs / vfs_write

write to 0xffff88811f8626dc of 4 bytes by task 21385 on cpu 1:
 inode_has_no_xattr include/linux/fs.h:3574 [inline]
 file_remove_privs+0x2e0/0x370 fs/inode.c:1943
 __generic_file_write_iter+0xda/0x330 mm/filemap.c:3393
 generic_file_write_iter+0x2f3/0x3e0 mm/filemap.c:3479
 call_write_iter include/linux/fs.h:1908 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0x607/0x690 fs/read_write.c:578
 ksys_pwrite64 fs/read_write.c:685 [inline]
 __do_sys_pwrite64 fs/read_write.c:695 [inline]
 __se_sys_pwrite64 fs/read_write.c:692 [inline]
 __x64_sys_pwrite64+0xf5/0x150 fs/read_write.c:692
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88811f8626dc of 4 bytes by task 21339 on cpu 0:
 iocb_flags include/linux/fs.h:3433 [inline]
 init_sync_kiocb include/linux/fs.h:2080 [inline]
 new_sync_write fs/read_write.c:499 [inline]
 vfs_write+0x363/0x690 fs/read_write.c:578
 ksys_pwrite64 fs/read_write.c:685 [inline]
 __do_sys_pwrite64 fs/read_write.c:695 [inline]
 __se_sys_pwrite64 fs/read_write.c:692 [inline]
 __x64_sys_pwrite64+0xf5/0x150 fs/read_write.c:692
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21339 Comm: syz-executor.0 Not tainted 5.8.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 21339 Comm: syz-executor.0 Not tainted 5.8.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x10f/0x19d lib/dump_stack.c:118
 panic+0x207/0x64a kernel/panic.c:231
 kcsan_report+0x684/0x690 kernel/kcsan/report.c:626
 kcsan_setup_watchpoint+0x453/0x4d0 kernel/kcsan/core.c:519
 iocb_flags include/linux/fs.h:3433 [inline]
 init_sync_kiocb include/linux/fs.h:2080 [inline]
 new_sync_write fs/read_write.c:499 [inline]
 vfs_write+0x363/0x690 fs/read_write.c:578
 ksys_pwrite64 fs/read_write.c:685 [inline]
 __do_sys_pwrite64 fs/read_write.c:695 [inline]
 __se_sys_pwrite64 fs/read_write.c:692 [inline]
 __x64_sys_pwrite64+0xf5/0x150 fs/read_write.c:692
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x416987
Code: Bad RIP value.
RSP: 002b:00007f8e6e94aa60 EFLAGS: 00000293 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 000000000050b240 RCX: 0000000000416987
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000078bf00 R08: fe03f80fe03f80ff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00000000ffffffff
R13: 0000000000000c55 R14: 00000000004ce97c R15: 00007f8e6e94b6d4
Kernel Offset: disabled
Rebooting in 86400 seconds..