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Commit a37372f6 authored by Jason Wessel's avatar Jason Wessel
Browse files

kdb: Prevent kernel oops with kdb_defcmd 



The kdb_defcmd can only be used to display the available command aliases
while using the kernel debug shell.  If you try to define a new macro
while the kernel debugger is active it will oops.  The debug shell
macros must use pre-allocated memory set aside at the time kdb_init()
is run, and the kdb_defcmd is restricted to only working at the time
that the kdb_init sequence is being run, which only occurs if you
actually activate the kernel debugger.

Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
parent 1b2caa2d

kernel/debug/kdb/kdb_main.c

+6 −2
Original line number Diff line number Diff line
@@ -681,6 +681,10 @@ static int kdb_defcmd(int argc, const char **argv) 
	}

	if (argc != 3)

		return KDB_ARGCOUNT;

	if (in_dbg_master()) {

		kdb_printf("Command only available during kdb_init()\n");

		return KDB_NOTIMP;

	}

	defcmd_set = kmalloc((defcmd_set_count + 1) * sizeof(*defcmd_set),

			     GFP_KDB);

	if (!defcmd_set)
@@ -2796,8 +2800,8 @@ static void __init kdb_inittab(void) 
	  "Stack traceback", 1, KDB_REPEAT_NONE);

	kdb_register_repeat("btp", kdb_bt, "<pid>",

	  "Display stack for process <pid>", 0, KDB_REPEAT_NONE);

	kdb_register_repeat("bta", kdb_bt, "[DRSTCZEUIMA]",

	  "Display stack all processes", 0, KDB_REPEAT_NONE);

	kdb_register_repeat("bta", kdb_bt, "[D|R|S|T|C|Z|E|U|I|M|A]",

	  "Backtrace all processes matching state flag", 0, KDB_REPEAT_NONE);

	kdb_register_repeat("btc", kdb_bt, "",

	  "Backtrace current process on each cpu", 0, KDB_REPEAT_NONE);

	kdb_register_repeat("btt", kdb_bt, "<vaddr>",