ozone: drm: Add fd number to crash keys when dmabuf mmap fails.

ui/ozone/platform/drm/common/client_native_pixmap_dmabuf.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/ozone/platform/drm/common/client_native_pixmap_dmabuf.h"
 
 #include <fcntl.h>
 #include <linux/version.h>
 #include <stddef.h>
 #include <sys/mman.h>
 #include <xf86drm.h>
 
 #include "base/debug/crash_logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/process/memory.h"
+#include "base/process/process_metrics.h"
 #include "base/strings/stringprintf.h"
 #include "base/trace_event/trace_event.h"
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 6, 0)
 #include <linux/types.h>
 
 struct local_dma_buf_sync {
   __u64 flags;
 };
 
@@ skipping 58 matching lines @@
   if (data_ == MAP_FAILED) {
     // TODO(dcastagna): Remove the following diagnostic information and the
     // associated crash keys once crbug.com/629521 is fixed.
     logging::SystemErrorCode mmap_error = logging::GetLastSystemErrorCode();
     bool fd_valid = fcntl(dmabuf_fd_.get(), F_GETFD) != -1 ||
                     logging::GetLastSystemErrorCode() != EBADF;
     std::string mmap_params = base::StringPrintf(
         "(addr=nullptr, length=%zu, prot=(PROT_READ | PROT_WRITE), "
         "flags=MAP_SHARED, fd=%d[valid=%d], offset=0)",
         map_size, dmabuf_fd_.get(), fd_valid);
+    std::string errno_str = logging::SystemErrorCodeToString(mmap_error);
+    std::unique_ptr<base::ProcessMetrics> process_metrics(
+        base::ProcessMetrics::CreateCurrentProcessMetrics());

[Daniele Castagna, 2017/03/02 02:05:04]

CreateCurrentProcessMetrics calls base::GetCurrentProcessHandle().
This won't probably work in the renderer since we're in a new pid namespace and
/proc is not remounted. We should access /proc/self instead of /proc/id.

[dshwang, 2017/03/02 19:59:31]

That's good point. By the way, it's base::GetCurrentProcessHandle()
implamantation issue, rather than this CL. Furthermore, even if the impl uses
"/proc/self", renderer still cannot read because of sandbox filesystem
protection. As renderer has no way, renderer will has just "-1" for it.

[Daniele Castagna, 2017/03/02 20:08:52]

Are you sure this works in the GPU process and the value you get is what you
expect?
Did you try to run this code even once in the browser/renderer/gpu process?

[dshwang, 2017/03/02 20:15:12]

I run this code in chromeos, and it works in only browser process. gpu process
never use this code, as this class is for client for gpu process.

+    std::string number_of_fds =
+        base::StringPrintf("%d", process_metrics->GetOpenFdCount());

[Daniele Castagna, 2017/03/02 02:05:04]

This would report -1 in case we're out of fds since we won't be able to open
/proc/{PID}/fd. Is that what you intended?

[dshwang, 2017/03/02 19:59:31]

OH, that's good point. I didn't think about it. Fortunately, it looks good. If
browser process report -1, we can think it reachs FD limit. so looks good to go.

[Daniele Castagna, 2017/03/02 20:08:52]

We were thinking of addding a UMA stat for openfds. As rsesek suggested, we
could open the fd for /proc/self/fd early and keep it open. In that way we
wouldn't have the problem of trying to open a dir when we might have reached the
fd limit.

[dshwang, 2017/03/02 20:15:12]

good to know. do you want to wait for UMA stat change?

     base::debug::ScopedCrashKey params_crash_key("mmap_params", mmap_params);
     base::debug::ScopedCrashKey size_crash_key("buffer_size", size.ToString());
-    base::debug::ScopedCrashKey errno_crash_key(
-        "errno", logging::SystemErrorCodeToString(mmap_error));
+    base::debug::ScopedCrashKey errno_crash_key("errno", errno_str);
+    base::debug::ScopedCrashKey number_of_fds_crash_key("number_of_fds",
+                                                        number_of_fds);
+    LOG(ERROR) << "Failed to mmap dmabuf; mmap_params: " << mmap_params
+               << ", buffer_size: (" << size.ToString()
+               << "),  errno: " << errno_str
+               << " , number_of_fds: " << number_of_fds;
     if (mmap_error == ENOMEM)
       base::TerminateBecauseOutOfMemory(map_size);
-    CHECK(false) << "Failed to mmap dmabuf.";
+    CHECK(false);
+    ;

[Daniele Castagna, 2017/03/02 02:05:04]

Why did you remove a useful log and just left a floating semi colon?

[dshwang, 2017/03/02 19:59:31]

Done.

   }
 }
 
 ClientNativePixmapDmaBuf::~ClientNativePixmapDmaBuf() {
   TRACE_EVENT0("drm", "~ClientNativePixmapDmaBuf");
   size_t map_size =
       pixmap_handle_.planes.back().offset + pixmap_handle_.planes.back().size;
   int ret = munmap(data_, map_size);
   DCHECK(!ret);
 }
@@ skipping 17 matching lines @@
   uint8_t* address = reinterpret_cast<uint8_t*>(data_);
   return address + pixmap_handle_.planes[plane].offset;
 }
 
 int ClientNativePixmapDmaBuf::GetStride(size_t plane) const {
   DCHECK_LT(plane, pixmap_handle_.planes.size());
   return pixmap_handle_.planes[plane].stride;
 }
 
 }  // namespace ui