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Commit 8fb6e3fd authored by Woody Lin's avatar Woody Lin
Browse files

InitFatalReboot: Trigger panic explicitly for init_fatal_panic 

The exit of init panics the system *after* process context (mm, stack,
...etc.) are recycled, according to Linux kernel's 'do_exit'
implementation. To preserve most init process context for debugging,
triggers the panic via proc-sysrq explicitly.

Note: after this change, there will be no "Attempt to kill init" panic
when androidboot.init_fatal_panic is set.

Test: Insert data abort fault in init, the full process context is
      preserved in memory dump captured after panic.
Bug: 155940351
Change-Id: I3393bd00f99b8cb432cfa19a105b7d636b411764
(cherry picked from commit be1cf900)
parent c00d57d3

init/reboot.cpp

+0 −2
Original line number Diff line number Diff line
@@ -66,8 +66,6 @@ 
#include "sigchld_handler.h"

#include "util.h"



#define PROC_SYSRQ "/proc/sysrq-trigger"



using namespace std::literals;



using android::base::boot_clock;

init/reboot_utils.cpp

+4 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <cutils/android_reboot.h>



#include "capabilities.h"

#include "reboot_utils.h"



namespace android {

namespace init {
@@ -138,6 +139,9 @@ void __attribute__((noreturn)) InitFatalReboot(int signal_number) { 
        LOG(ERROR) << backtrace->FormatFrameData(i);

    }

    if (init_fatal_panic) {

        LOG(ERROR) << __FUNCTION__ << ": Trigger crash";

        android::base::WriteStringToFile("c", PROC_SYSRQ);

        LOG(ERROR) << __FUNCTION__ << ": Sys-Rq failed to crash the system; fallback to exit().";

        _exit(signal_number);

    }

    RebootSystem(ANDROID_RB_RESTART2, init_fatal_reboot_target);

init/reboot_utils.h

+2 −0
Original line number Diff line number Diff line
@@ -18,6 +18,8 @@ 


#include <string>



#define PROC_SYSRQ "/proc/sysrq-trigger"



namespace android {

namespace init {