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kgdb: Always process the whole breakpoint list on activate or deactivate
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This patch fixes 2 edge cases in using kgdb in conjunction with gdb.

1) kgdb_deactivate_sw_breakpoints() should process the entire array of
   breakpoints.  The failure to do so results in breakpoints that you
   cannot remove, because a break point can only be removed if its
   state flag is set to BP_SET.

   The easy way to duplicate this problem is to plant a break point in
   a kernel module and then unload the kernel module.

2) kgdb_activate_sw_breakpoints() should process the entire array of
   breakpoints.  The failure to do so results in missed breakpoints
   when a breakpoint cannot be activated.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
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Jason Wessel committed Dec 11, 2009
1 parent d625e9c commit 7f8b7ed
Showing 1 changed file with 15 additions and 8 deletions.
23 changes: 15 additions & 8 deletions kernel/kgdb.c
Original file line number Diff line number Diff line change
Expand Up @@ -625,7 +625,8 @@ static void kgdb_flush_swbreak_addr(unsigned long addr)
static int kgdb_activate_sw_breakpoints(void)
{
unsigned long addr;
int error = 0;
int error;
int ret = 0;
int i;

for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
Expand All @@ -635,13 +636,16 @@ static int kgdb_activate_sw_breakpoints(void)
addr = kgdb_break[i].bpt_addr;
error = kgdb_arch_set_breakpoint(addr,
kgdb_break[i].saved_instr);
if (error)
return error;
if (error) {
ret = error;
printk(KERN_INFO "KGDB: BP install failed: %lx", addr);
continue;
}

kgdb_flush_swbreak_addr(addr);
kgdb_break[i].state = BP_ACTIVE;
}
return 0;
return ret;
}

static int kgdb_set_sw_break(unsigned long addr)
Expand Down Expand Up @@ -688,7 +692,8 @@ static int kgdb_set_sw_break(unsigned long addr)
static int kgdb_deactivate_sw_breakpoints(void)
{
unsigned long addr;
int error = 0;
int error;
int ret = 0;
int i;

for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
Expand All @@ -697,13 +702,15 @@ static int kgdb_deactivate_sw_breakpoints(void)
addr = kgdb_break[i].bpt_addr;
error = kgdb_arch_remove_breakpoint(addr,
kgdb_break[i].saved_instr);
if (error)
return error;
if (error) {
printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr);
ret = error;
}

kgdb_flush_swbreak_addr(addr);
kgdb_break[i].state = BP_SET;
}
return 0;
return ret;
}

static int kgdb_remove_sw_break(unsigned long addr)
Expand Down

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