fix: handle no memory limit in coder stat mem (#11107)

cli/clistat/cgroup.go

@@ -44,6 +44,13 @@ const (
 	cgroupV2MemoryStat = "/sys/fs/cgroup/memory.stat"
 )
 
+const (
+	// 9223372036854771712 is the highest positive signed 64-bit integer (263-1),
+	// rounded down to multiples of 4096 (2^12), the most common page size on x86 systems.
+	// This is used by docker to indicate no memory limit.
+	UnlimitedMemory int64 = 9223372036854771712
+)
+
 // ContainerCPU returns the CPU usage of the container cgroup.
 // This is calculated as difference of two samples of the
 // CPU usage of the container cgroup.
@@ -271,6 +278,10 @@ func (s *Statter) cGroupV1Memory(p Prefix) (*Result, error) {
 		// Nonetheless, if it is not, assume there is no limit set.
 		maxUsageBytes = -1
 	}
+	// Set to unlimited if we detect the unlimited docker value.
+	if maxUsageBytes == UnlimitedMemory {
+		maxUsageBytes = -1
+	}
 
 	// need a space after total_rss so we don't hit something else
 	usageBytes, err := readInt64(s.fs, cgroupV1MemoryUsageBytes)

cli/clistat/stat_internal_test.go

@@ -197,6 +197,18 @@ func TestStatter(t *testing.T) {
 			assert.Nil(t, mem.Total)
 			assert.Equal(t, "B", mem.Unit)
 		})
+		t.Run("ContainerMemory/NoLimit", func(t *testing.T) {
+			t.Parallel()
+			fs := initFS(t, fsContainerCgroupV1DockerNoMemoryLimit)
+			s, err := New(WithFS(fs), withNoWait)
+			require.NoError(t, err)
+			mem, err := s.ContainerMemory(PrefixDefault)
+			require.NoError(t, err)
+			require.NotNil(t, mem)
+			assert.Equal(t, 268435456.0, mem.Used)
+			assert.Nil(t, mem.Total)
+			assert.Equal(t, "B", mem.Unit)
+		})
 	})
 
 	t.Run("CGroupV2", func(t *testing.T) {
@@ -384,6 +396,17 @@ proc /proc/sys proc ro,nosuid,nodev,noexec,relatime 0 0`,
 		cgroupV1MemoryUsageBytes:    "536870912",
 		cgroupV1MemoryStat:          "total_inactive_file 268435456",
 	}
+	fsContainerCgroupV1DockerNoMemoryLimit = map[string]string{
+		procOneCgroup: "0::/docker/aa86ac98959eeedeae0ecb6e0c9ddd8ae8b97a9d0fdccccf7ea7a474f4e0bb1f",
+		procMounts: `overlay / overlay rw,relatime,lowerdir=/some/path:/some/path,upperdir=/some/path:/some/path,workdir=/some/path:/some/path 0 0
+proc /proc/sys proc ro,nosuid,nodev,noexec,relatime 0 0`,
+		cgroupV1CPUAcctUsage:        "0",
+		cgroupV1CFSQuotaUs:          "-1",
+		cgroupV1CFSPeriodUs:         "100000",
+		cgroupV1MemoryMaxUsageBytes: "9223372036854771712",
+		cgroupV1MemoryUsageBytes:    "536870912",
+		cgroupV1MemoryStat:          "total_inactive_file 268435456",
+	}
 	fsContainerCgroupV1AltPath = map[string]string{
 		procOneCgroup: "0::/docker/aa86ac98959eeedeae0ecb6e0c9ddd8ae8b97a9d0fdccccf7ea7a474f4e0bb1f",
 		procMounts: `overlay / overlay rw,relatime,lowerdir=/some/path:/some/path,upperdir=/some/path:/some/path,workdir=/some/path:/some/path 0 0