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a4c68ee857
When sending SIGUSR1 to the daemon, it can crash because of a concurrent map access panic, showing a stack trace involving dumpDaemon. It appears it's not possible to recover from a concurrent map access panic. Since it's important that SIGUSR1 not be a destructive operation, sadly the best course of action I can think of is to remove this functionality. Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
46 lines
1.4 KiB
Go
46 lines
1.4 KiB
Go
package daemon
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import (
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"fmt"
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"os"
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"syscall"
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"unsafe"
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winio "github.com/Microsoft/go-winio"
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"github.com/Sirupsen/logrus"
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"github.com/docker/docker/pkg/signal"
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"github.com/docker/docker/pkg/system"
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)
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func (d *Daemon) setupDumpStackTrap(root string) {
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// Windows does not support signals like *nix systems. So instead of
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// trapping on SIGUSR1 to dump stacks, we wait on a Win32 event to be
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// signaled. ACL'd to builtin administrators and local system
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ev := "Global\\docker-daemon-" + fmt.Sprint(os.Getpid())
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sd, err := winio.SddlToSecurityDescriptor("D:P(A;;GA;;;BA)(A;;GA;;;SY)")
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if err != nil {
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logrus.Errorf("failed to get security descriptor for debug stackdump event %s: %s", ev, err.Error())
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return
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}
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var sa syscall.SecurityAttributes
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sa.Length = uint32(unsafe.Sizeof(sa))
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sa.InheritHandle = 1
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sa.SecurityDescriptor = uintptr(unsafe.Pointer(&sd[0]))
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h, err := system.CreateEvent(&sa, false, false, ev)
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if h == 0 || err != nil {
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logrus.Errorf("failed to create debug stackdump event %s: %s", ev, err.Error())
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return
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}
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go func() {
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logrus.Debugf("Stackdump - waiting signal at %s", ev)
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for {
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syscall.WaitForSingleObject(h, syscall.INFINITE)
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path, err := signal.DumpStacks(root)
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if err != nil {
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logrus.WithError(err).Error("failed to write goroutines dump")
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} else {
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logrus.Infof("goroutine stacks written to %s", path)
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}
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}
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}()
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}
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