==================================================================
BUG: KCSAN: data-race in do_readv / do_readv

read to 0xffff88811b3daa68 of 8 bytes by task 12705 on cpu 0:
 do_readv+0xb1/0x250 fs/read_write.c:1031
 __do_sys_readv fs/read_write.c:1125 [inline]
 __se_sys_readv fs/read_write.c:1122 [inline]
 __x64_sys_readv+0x4e/0x60 fs/read_write.c:1122
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88811b3daa68 of 8 bytes by task 12707 on cpu 1:
 do_readv+0x113/0x250 fs/read_write.c:1036
 __do_sys_readv fs/read_write.c:1125 [inline]
 __se_sys_readv fs/read_write.c:1122 [inline]
 __x64_sys_readv+0x4e/0x60 fs/read_write.c:1122
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12707 Comm: syz-executor.4 Not tainted 5.4.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 12707 Comm: syz-executor.4 Not tainted 5.4.0-rc7+ #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+0x11d/0x181 lib/dump_stack.c:118
 panic+0x210/0x640 kernel/panic.c:221
 kcsan_report.cold+0xc/0xd kernel/kcsan/report.c:315
 kcsan_setup_watchpoint+0x3fe/0x460 kernel/kcsan/core.c:423
 check_access kernel/kcsan/core.c:466 [inline]
 __tsan_write8 kernel/kcsan/core.c:596 [inline]
 __tsan_unaligned_write8+0xc4/0x100 kernel/kcsan/core.c:596
 do_readv+0x113/0x250 fs/read_write.c:1036
 __do_sys_readv fs/read_write.c:1125 [inline]
 __se_sys_readv fs/read_write.c:1122 [inline]
 __x64_sys_readv+0x4e/0x60 fs/read_write.c:1122
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45a639
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f64f7d24c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a639
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 000000000075c118 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f64f7d256d4
R13: 00000000004c7ecd R14: 00000000004de160 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..