Messages in this thread Patch in this message | | | Date | Mon, 10 Dec 2012 15:37:22 -0600 | From | John Blackwood <> | Subject | [PATCH] kgdb/kdb: A fix for kdb command table expansion |
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When locally adding in some additional kdb commands, I stumbled across an issue with the dynamic expansion of the kdb command table. When the number of kdb commands exceeds the size of the statically allocated kdb_base_commands[] array, additional space is allocated in the kdb_register_repeat() routine.
The unused portion of the newly allocated array was not being initialized to zero properly and this would result in segfaults when help '?' was executed or when a search for a non-existing command would traverse the command table beyond the end of valid command entries and then attempt to use the non-zeroed area as actual command entries.
Signed-off-by: John Blackwood <john.blackwood@ccur.com> Index: b/kernel/debug/kdb/kdb_main.c =================================================================== --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -3341,7 +3341,7 @@ int kdb_register_repeat(char *cmd, (kdb_max_commands - KDB_BASE_CMD_MAX) * sizeof(*new)); kfree(kdb_commands); } - memset(new + kdb_max_commands, 0, + memset(new + kdb_max_commands - KDB_BASE_CMD_MAX, 0, kdb_command_extend * sizeof(*new)); kdb_commands = new; kp = kdb_commands + kdb_max_commands - KDB_BASE_CMD_MAX;
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