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Commit 60dbeef4 authored by Alexander Potapenko's avatar Alexander Potapenko
Browse files

BootReceiver: cap the number of sent kernel memory corruptions 



Save the bandwidth by sending only the first few reports from a running
kernel.

Also fix a bug in the old code (strings must be compared with equals()).

Bug: 172316664
Bug: 182159975
Test: running KFENCE manually
Signed-off-by: default avatarAlexander Potapenko <glider@google.com>
Change-Id: I3eb13596b5d9006637e110d000f64c46661cac4d
parent 66a4de06

services/core/java/com/android/server/BootReceiver.java

+6 −2
Original line number Diff line number Diff line
@@ -128,6 +128,9 @@ public class BootReceiver extends BroadcastReceiver { 
    // Location of ftrace pipe for notifications from kernel memory tools like KFENCE and KASAN.

    private static final String ERROR_REPORT_TRACE_PIPE =

            "/sys/kernel/tracing/instances/bootreceiver/trace_pipe";

    // Stop after sending this many reports. See http://b/182159975.

    private static final int MAX_ERROR_REPORTS = 8;

    private static int sSentReports = 0;

    // Avoid reporing the same bug from processDmesg() twice.

    private static String sLastReportedBug = null;
@@ -301,7 +304,7 @@ public class BootReceiver extends BroadcastReceiver { 
     *    - repeat the above steps till the last report is found.

     */

    private void processDmesg(Context ctx) throws IOException {



        if (sSentReports == MAX_ERROR_REPORTS) return;

        /*

         * Only SYSTEM_KASAN_ERROR_REPORT and SYSTEM_KFENCE_ERROR_REPORT are supported at the

         * moment.
@@ -352,7 +355,7 @@ public class BootReceiver extends BroadcastReceiver { 
        }



        // Avoid sending the same bug report twice.

        if (bugTitle == sLastReportedBug) return;

        if (bugTitle.equals(sLastReportedBug)) return;



        final String reportTag = "SYSTEM_" + tool + "_ERROR_REPORT";

        final DropBoxManager db = ctx.getSystemService(DropBoxManager.class);
@@ -361,6 +364,7 @@ public class BootReceiver extends BroadcastReceiver { 


        addTextToDropBox(db, reportTag, reportText, "/dev/kmsg", LOG_SIZE);

        sLastReportedBug = bugTitle;

        sSentReports++;

    }



    private void removeOldUpdatePackages(Context context) {