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Commit dce4d06b authored by Ben Cheng's avatar Ben Cheng
Browse files

Fix overflow prevention code in memory dump. 

The delta between start and end pointers in memory dump has to be
multiples of 4 or 16.

Bug: 3486787
Change-Id: Ie34aa79ffb704ca647805dbc6a16f2c35adf849c
parent 0e7c4274

debuggerd/arm/machine.c

+23 −19
Original line number Diff line number Diff line
@@ -54,7 +54,7 @@ void dump_stack_and_code(int tfd, int pid, mapinfo *map, 
                         int unwind_depth, unsigned int sp_list[],

                         bool at_fault)

{

    unsigned int sp, pc, p, end, data;

    unsigned int sp, pc, lr, p, end, data;

    struct pt_regs r;

    int sp_depth;

    bool only_in_tombstone = !at_fault;
@@ -63,23 +63,25 @@ void dump_stack_and_code(int tfd, int pid, mapinfo *map, 
    if(ptrace(PTRACE_GETREGS, pid, 0, &r)) return;

    sp = r.ARM_sp;

    pc = r.ARM_pc;

    lr = r.ARM_lr;



    _LOG(tfd, only_in_tombstone, "\ncode around pc:\n");



    end = p = pc & ~3;

    p = pc & ~3;

    p -= 32;

    if (p > end)

    if (p > pc)

        p = 0;

    end += 32;

    if (end < p)

        end = ~0;

    end = p + 80;

    /* 'end - p' has to be multiples of 16 */

    while (end < p)

        end -= 16;



    /* Dump the code around PC as:

     *  addr       contents

     *  00008d34   fffffcd0 4c0eb530 b0934a0e 1c05447c

     *  00008d44   f7ff18a0 490ced94 68035860 d0012b00

     */

    while (p <= end) {

    while (p <  end) {

        int i;



        sprintf(code_buffer, "%08x ", p);
@@ -91,23 +93,24 @@ void dump_stack_and_code(int tfd, int pid, mapinfo *map, 
        _LOG(tfd, only_in_tombstone, "%s\n", code_buffer);

    }



    if ((unsigned) r.ARM_lr != pc) {

    if (lr != pc) {

        _LOG(tfd, only_in_tombstone, "\ncode around lr:\n");



        end = p = r.ARM_lr & ~3;

        p = lr & ~3;

        p -= 32;

        if (p > end)

        if (p > lr)

            p = 0;

        end += 32;

        if (end < p)

            end = ~0;

        end = p + 80;

        /* 'end - p' has to be multiples of 16 */

        while (end < p)

            end -= 16;



        /* Dump the code around LR as:

         *  addr       contents

         *  00008d34   fffffcd0 4c0eb530 b0934a0e 1c05447c

         *  00008d44   f7ff18a0 490ced94 68035860 d0012b00

         */

        while (p <= end) {

        while (p < end) {

            int i;



            sprintf(code_buffer, "%08x ", p);
@@ -133,10 +136,10 @@ void dump_stack_and_code(int tfd, int pid, mapinfo *map, 
        }

    }

    else {

        end = sp | 0x000000ff;

        end += 0xff;

        if (end < sp)

            end = ~0;

        end = p + 256;

        /* 'end - p' has to be multiples of 4 */

        if (end < p)

            end = ~7;

    }



    _LOG(tfd, only_in_tombstone, "\nstack:\n");
@@ -174,8 +177,9 @@ void dump_stack_and_code(int tfd, int pid, mapinfo *map, 
    /* print another 64-byte of stack data after the last frame */



    end = p+64;

    /* 'end - p' has to be multiples of 4 */

    if (end < p)

        end = ~0;

        end = ~7;



    while (p <= end) {

         data = ptrace(PTRACE_PEEKTEXT, pid, (void*)p, NULL);