WARNING: DATA RACE
Write at 0x00c000af16c8 by goroutine 337:
  gvisor.googlesource.com/gvisor/pkg/sentry/fs/tty.(*queue).WriteFromBlocks()
      pkg/sentry/fs/tty/queue.go:246 +0x2a6
  gvisor.googlesource.com/gvisor/pkg/sentry/safemem.Writer.WriteFromBlocks-fm()
      pkg/sentry/safemem/io.go:46 +0x75
  gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).withInternalMappings()
      pkg/sentry/mm/io.go:503 +0x8ac
  gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).withVecInternalMappings()
      pkg/sentry/mm/io.go:572 +0x964
  gvisor.googlesource.com/gvisor/pkg/sentry/mm.(*MemoryManager).CopyInTo()
      pkg/sentry/mm/io.go:309 +0x1f1
  gvisor.googlesource.com/gvisor/pkg/sentry/fs/tty.(*queue).write()
      pkg/sentry/usermem/usermem.go:543 +0x164
  gvisor.googlesource.com/gvisor/pkg/sentry/fs/tty.(*lineDiscipline).inputQueueWrite()
      pkg/sentry/fs/tty/line_discipline.go:205 +0x147
  gvisor.googlesource.com/gvisor/pkg/sentry/fs/tty.(*masterFileOperations).Write()
      pkg/sentry/fs/tty/master.go:141 +0x11c
  gvisor.googlesource.com/gvisor/pkg/sentry/fs.(*File).Writev()
      pkg/sentry/fs/file.go:314 +0x1fc
  gvisor.googlesource.com/gvisor/pkg/sentry/syscalls/linux.writev()
      pkg/sentry/syscalls/linux/sys_write.go:261 +0xe0
  gvisor.googlesource.com/gvisor/pkg/sentry/syscalls/linux.Write()
      pkg/sentry/syscalls/linux/sys_write.go:71 +0x293
  gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).executeSyscall()
      pkg/sentry/kernel/task_syscall.go:165 +0x407
  gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).doSyscallInvoke()
      pkg/sentry/kernel/task_syscall.go:283 +0xb4
  gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).doSyscallEnter()
      pkg/sentry/kernel/task_syscall.go:244 +0x109
  gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).doSyscall()
      pkg/sentry/kernel/task_syscall.go:219 +0x1b6
  gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*runApp).execute()
      pkg/sentry/kernel/task_run.go:215 +0x1852
  gvisor.googlesource.com/gvisor/pkg/sentry/kernel.(*Task).run()
      pkg/sentry/kernel/task_run.go:91 +0x2e5

Previous read at 0x00c000af16c8 by goroutine 350:
  gvisor.googlesource.com/gvisor/pkg/sentry/fs/tty.(*lineDiscipline).masterReadiness()
      pkg/sentry/fs/tty/queue.go:121 +0x43
DIAGNOSIS:
I0331 03:33:34.591364   49838 x:0] ***************************
I0331 03:33:34.591523   49838 x:0] Args: [/syzkaller/managers/ptrace-proxy-sandbox-race/current/image -root /syzkaller/managers/ptrace-proxy-sandbox-race/workdir/gvisor_root -watchdog-action=panic -network=none -debug -platform=ptrace -file-access=shared -network=sandbox debug -stacks ci-gvisor-ptrace-proxy-sandbox-race-2]
I0331 03:33:34.591606   49838 x:0] Git Revision: a046054ba35e8d8c4882f9311dc964eaa1497d58
I0331 03:33:34.591643   49838 x:0] PID: 49838
I0331 03:33:34.591671   49838 x:0] UID: 0, GID: 0
I0331 03:33:34.591687   49838 x:0] Configuration:
I0331 03:33:34.591708   49838 x:0] 		RootDir: /syzkaller/managers/ptrace-proxy-sandbox-race/workdir/gvisor_root
I0331 03:33:34.591720   49838 x:0] 		Platform: ptrace
I0331 03:33:34.591745   49838 x:0] 		FileAccess: shared, overlay: false
I0331 03:33:34.591777   49838 x:0] 		Network: sandbox, logging: false
I0331 03:33:34.591809   49838 x:0] 		Strace: false, max size: 1024, syscalls: []
I0331 03:33:34.591844   49838 x:0] ***************************
D0331 03:33:34.591900   49838 x:0] Load container "/syzkaller/managers/ptrace-proxy-sandbox-race/workdir/gvisor_root" "ci-gvisor-ptrace-proxy-sandbox-race-2"
D0331 03:33:34.597734   49838 x:0] Signal container "ci-gvisor-ptrace-proxy-sandbox-race-2": signal 0
D0331 03:33:34.597826   49838 x:0] Signal sandbox "ci-gvisor-ptrace-proxy-sandbox-race-2"
D0331 03:33:34.597872   49838 x:0] Connecting to sandbox "ci-gvisor-ptrace-proxy-sandbox-race-2"
D0331 03:33:34.598601   49838 x:0] urpc: successfully marshalled 117 bytes.
D0331 03:33:34.599702   49838 x:0] urpc: unmarshal success.
I0331 03:33:34.599816   49838 x:0] Found sandbox "ci-gvisor-ptrace-proxy-sandbox-race-2", PID: 43776
I0331 03:33:34.599898   49838 x:0] Retrieving sandbox stacks
D0331 03:33:34.599947   49838 x:0] Stacks sandbox "ci-gvisor-ptrace-proxy-sandbox-race-2"
D0331 03:33:34.600005   49838 x:0] Connecting to sandbox "ci-gvisor-ptrace-proxy-sandbox-race-2"
D0331 03:33:34.600134   49838 x:0] urpc: successfully marshalled 36 bytes.
D0331 03:33:34.748145   49838 x:0] urpc: unmarshal success.
I0331 03:33:34.748301   49838 x:0]      *** Stack dump ***
goroutine 16942 [running]:
gvisor.googlesource.com/gvisor/pkg/log.Stacks(0x45c801, 0xc0002a4c60, 0xc000188b70, 0xc000160000)
	pkg/log/log.go:259 +0xb6
gvisor.googlesource.com/gvisor/runsc/boot.(*debug).Stacks(0x23cfc78, 0x23cfc78, 0xc0003bc150, 0x0, 0x0)
	runsc/boot/debug.go:26 +0x38
reflect.Value.call(0xc0002a4c60, 0xc0002a21f8, 0x13, 0x112796b, 0x4, 0xc000ce1eb8, 0x3, 0x3, 0x4a864e, 0xfda2e0, ...)
	GOROOT/src/reflect/value.go:447 +0x649
reflect.Value.Call(0xc0002a4c60, 0xc0002a21f8, 0x13, 0xc000ce1eb8, 0x3, 0x3, 0x0, 0x23cfc78, 0x16)
	GOROOT/src/reflect/value.go:308 +0xc1
gvisor.googlesource.com/gvisor/pkg/urpc.(*Server).handleOne(0xc0002ae840, 0xc0007800c0, 0x0, 0x0)
	pkg/urpc/urpc.go:325 +0x63f
gvisor.googlesource.com/gvisor/pkg/urpc.(*Server).handleRegistered(0xc0002ae840, 0xc0007800c0, 0xc0002ae840, 0xc0007800c0)
	pkg/urpc/urpc.go:420 +0x43
gvisor.googlesource.com/gvisor/pkg/urpc.(*Server).StartHandling.func1(0xc0002ae840, 0xc0007800c0)
	pkg/urpc/urpc.go:440 +0x77
created by gvisor.googlesource.com/gvisor/pkg/urpc.(*Server).StartHandling
	pkg/urpc/urpc.go:438 +0x6f