From f7c82d5a3c537a4b4d9d0395db4606bf4d3c7a5f Mon Sep 17 00:00:00 2001 From: John Blackwood Date: Mon, 10 Dec 2012 15:37:22 -0600 Subject: kdb: A fix for kdb command table expansion 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 Signed-off-by: Jason Wessel --- kernel/debug/kdb/kdb_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/debug/kdb') diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 8875254..a52493a 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -2739,7 +2739,7 @@ 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; -- cgit v1.1 From 5f784f798c1a6367d314b3ea5d742a5dcc8dc7ca Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Thu, 20 Dec 2012 14:11:27 -0500 Subject: kdb: use ARRAY_SIZE where possible Signed-off-by: Sasha Levin Signed-off-by: Jason Wessel --- kernel/debug/kdb/kdb_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/debug/kdb') diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index a52493a..437b74d 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -124,7 +124,7 @@ static kdbmsg_t kdbmsgs[] = { }; #undef KDBMSG -static const int __nkdb_err = sizeof(kdbmsgs) / sizeof(kdbmsg_t); +static const int __nkdb_err = ARRAY_SIZE(kdbmsgs); /* @@ -175,7 +175,7 @@ static char *__env[] = { (char *)0, }; -static const int __nenv = (sizeof(__env) / sizeof(char *)); +static const int __nenv = ARRAY_SIZE(__env); struct task_struct *kdb_curr_task(int cpu) { -- cgit v1.1 From 00370b8f8dd6e3171b8202f9c5187a5f73e99497 Mon Sep 17 00:00:00 2001 From: Matt Klein Date: Wed, 2 Jan 2013 13:20:49 -0800 Subject: kdb: Setup basic kdb state before invoking commands via kgdb Although invasive kdb commands are not supported via kgdb, some useful non-invasive commands like bt* require basic kdb state to be setup before calling into the kdb code. Factor out some of this code and call it before and after executing kdb commands via kgdb. Signed-off-by: Matt Klein Signed-off-by: Jason Wessel --- kernel/debug/kdb/kdb_debugger.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) (limited to 'kernel/debug/kdb') diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c index be7b33b..d04a6ce 100644 --- a/kernel/debug/kdb/kdb_debugger.c +++ b/kernel/debug/kdb/kdb_debugger.c @@ -34,6 +34,22 @@ EXPORT_SYMBOL_GPL(kdb_poll_idx); static struct kgdb_state *kdb_ks; +int kdb_common_init_state(struct kgdb_state *ks) +{ + kdb_initial_cpu = atomic_read(&kgdb_active); + kdb_current_task = kgdb_info[ks->cpu].task; + kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo; + return 0; +} + +int kdb_common_deinit_state(void) +{ + kdb_initial_cpu = -1; + kdb_current_task = NULL; + kdb_current_regs = NULL; + return 0; +} + int kdb_stub(struct kgdb_state *ks) { int error = 0; @@ -94,9 +110,7 @@ int kdb_stub(struct kgdb_state *ks) } /* Set initial kdb state variables */ KDB_STATE_CLEAR(KGDB_TRANS); - kdb_initial_cpu = atomic_read(&kgdb_active); - kdb_current_task = kgdb_info[ks->cpu].task; - kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo; + kdb_common_init_state(ks); /* Remove any breakpoints as needed by kdb and clear single step */ kdb_bp_remove(); KDB_STATE_CLEAR(DOING_SS); @@ -125,9 +139,7 @@ int kdb_stub(struct kgdb_state *ks) * Upon exit from the kdb main loop setup break points and restart * the system based on the requested continue state */ - kdb_initial_cpu = -1; - kdb_current_task = NULL; - kdb_current_regs = NULL; + kdb_common_deinit_state(); KDB_STATE_CLEAR(PAGER); kdbnearsym_cleanup(); if (error == KDB_CMD_KGDB) { -- cgit v1.1 From 4eb7a66d9410927fb8fbafad8b8298b627cdd128 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Sun, 3 Feb 2013 09:32:28 -0600 Subject: kdb: Fix overlap in buffers with strcpy Maxime reported that strcpy(s->usage, s->usage+1) has no definitive guarantee that it will work on all archs the same way when you have overlapping memory. The fix is simple for the kdb code because we still have the original string memory in the function scope, so we just have to use that as the argument instead. Reported-by: Maxime Villard Signed-off-by: Jason Wessel --- kernel/debug/kdb/kdb_main.c | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) (limited to 'kernel/debug/kdb') diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 437b74d..de22c8c 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -683,32 +683,44 @@ static int kdb_defcmd(int argc, const char **argv) return KDB_ARGCOUNT; defcmd_set = kmalloc((defcmd_set_count + 1) * sizeof(*defcmd_set), GFP_KDB); - if (!defcmd_set) { - kdb_printf("Could not allocate new defcmd_set entry for %s\n", - argv[1]); - defcmd_set = save_defcmd_set; - return KDB_NOTIMP; - } + if (!defcmd_set) + goto fail_defcmd; memcpy(defcmd_set, save_defcmd_set, defcmd_set_count * sizeof(*defcmd_set)); - kfree(save_defcmd_set); s = defcmd_set + defcmd_set_count; memset(s, 0, sizeof(*s)); s->usable = 1; s->name = kdb_strdup(argv[1], GFP_KDB); + if (!s->name) + goto fail_name; s->usage = kdb_strdup(argv[2], GFP_KDB); + if (!s->usage) + goto fail_usage; s->help = kdb_strdup(argv[3], GFP_KDB); + if (!s->help) + goto fail_help; if (s->usage[0] == '"') { - strcpy(s->usage, s->usage+1); + strcpy(s->usage, argv[2]+1); s->usage[strlen(s->usage)-1] = '\0'; } if (s->help[0] == '"') { - strcpy(s->help, s->help+1); + strcpy(s->help, argv[3]+1); s->help[strlen(s->help)-1] = '\0'; } ++defcmd_set_count; defcmd_in_progress = 1; + kfree(save_defcmd_set); return 0; +fail_help: + kfree(s->usage); +fail_usage: + kfree(s->name); +fail_name: + kfree(defcmd_set); +fail_defcmd: + kdb_printf("Could not allocate new defcmd_set entry for %s\n", argv[1]); + defcmd_set = save_defcmd_set; + return KDB_NOTIMP; } /* -- cgit v1.1 From 074604af21c971cf2fcfaa0f6012b4b0c9ca891a Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Mon, 4 Feb 2013 09:52:14 -0600 Subject: kdb_main: fix help print The help command was chopping all the usage instructions such that they were not readable. Example: bta [D|R|S|T|C|Z|E|U|I| Backtrace all processes matching state flag per_cpu [] [ [] [] Display per_cpu variables All that is needed is to check the how long the cmd_usage is and jump to the next line when appropriate. Signed-off-by: Jason Wessel --- kernel/debug/kdb/kdb_main.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'kernel/debug/kdb') diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index de22c8c..25908cf 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -2442,11 +2442,15 @@ static int kdb_help(int argc, const char **argv) kdb_printf("-----------------------------" "-----------------------------\n"); for_each_kdbcmd(kt, i) { - if (kt->cmd_name) - kdb_printf("%-15.15s %-20.20s %s\n", kt->cmd_name, - kt->cmd_usage, kt->cmd_help); + char *space = ""; if (KDB_FLAG(CMD_INTERRUPT)) return 0; + if (!kt->cmd_name) + continue; + if (strlen(kt->cmd_usage) > 20) + space = "\n "; + kdb_printf("%-15.15s %-20s%s%s\n", kt->cmd_name, + kt->cmd_usage, space, kt->cmd_help); } return 0; } -- cgit v1.1 From 1b2caa2dcb8f18d2be9c5c3c992cb6da03f1a70a Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Mon, 4 Feb 2013 10:35:33 -0600 Subject: kdb: Remove the ll command Recently some code inspection was done after fixing a problem with kmalloc used while in the kernel debugger context (which is not legal), and it turned up the fact that kdb ll command will oops the kernel. Given that there have been zero bug reports on the command combined with the fact it will oops the kernel it is clearly not being used. Instead of fixing it, it will be removed. Signed-off-by: Jason Wessel --- kernel/debug/kdb/kdb_main.c | 65 --------------------------------------------- 1 file changed, 65 deletions(-) (limited to 'kernel/debug/kdb') diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 25908cf..cdfc0a7 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -2362,69 +2362,6 @@ static int kdb_pid(int argc, const char **argv) return 0; } -/* - * kdb_ll - This function implements the 'll' command which follows a - * linked list and executes an arbitrary command for each - * element. - */ -static int kdb_ll(int argc, const char **argv) -{ - int diag = 0; - unsigned long addr; - long offset = 0; - unsigned long va; - unsigned long linkoffset; - int nextarg; - const char *command; - - if (argc != 3) - return KDB_ARGCOUNT; - - nextarg = 1; - diag = kdbgetaddrarg(argc, argv, &nextarg, &addr, &offset, NULL); - if (diag) - return diag; - - diag = kdbgetularg(argv[2], &linkoffset); - if (diag) - return diag; - - /* - * Using the starting address as - * the first element in the list, and assuming that - * the list ends with a null pointer. - */ - - va = addr; - command = kdb_strdup(argv[3], GFP_KDB); - if (!command) { - kdb_printf("%s: cannot duplicate command\n", __func__); - return 0; - } - /* Recursive use of kdb_parse, do not use argv after this point */ - argv = NULL; - - while (va) { - char buf[80]; - - if (KDB_FLAG(CMD_INTERRUPT)) - goto out; - - sprintf(buf, "%s " kdb_machreg_fmt "\n", command, va); - diag = kdb_parse(buf); - if (diag) - goto out; - - addr = va + linkoffset; - if (kdb_getword(&va, addr, sizeof(va))) - goto out; - } - -out: - kfree(command); - return diag; -} - static int kdb_kgdb(int argc, const char **argv) { return KDB_CMD_KGDB; @@ -2866,8 +2803,6 @@ static void __init kdb_inittab(void) kdb_register_repeat("btt", kdb_bt, "", "Backtrace process given its struct task address", 0, KDB_REPEAT_NONE); - kdb_register_repeat("ll", kdb_ll, " ", - "Execute cmd for each element in linked list", 0, KDB_REPEAT_NONE); kdb_register_repeat("env", kdb_env, "", "Show environment variables", 0, KDB_REPEAT_NONE); kdb_register_repeat("set", kdb_set, "", -- cgit v1.1 From a37372f6c3c03dc7613eaae8bb3458c8068f5fff Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Mon, 4 Feb 2013 10:35:33 -0600 Subject: 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: Jason Wessel --- kernel/debug/kdb/kdb_main.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'kernel/debug/kdb') diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index cdfc0a7..496f596 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -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, "", "Display stack for process ", 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, "", -- cgit v1.1 From 36dfea42cc35509b481377980338cc3b89d79256 Mon Sep 17 00:00:00 2001 From: Vincent Date: Tue, 12 Feb 2013 11:34:15 +0100 Subject: kdb: Remove unhandled ssb command MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The 'ssb' command can only be handled when we have a disassembler, to check for branches, so remove the 'ssb' command for now. Signed-off-by: Vincent Stehlé Signed-off-by: Jason Wessel --- kernel/debug/kdb/kdb_bp.c | 20 ++------------------ kernel/debug/kdb/kdb_debugger.c | 1 - kernel/debug/kdb/kdb_main.c | 16 ---------------- kernel/debug/kdb/kdb_private.h | 4 ---- 4 files changed, 2 insertions(+), 39 deletions(-) (limited to 'kernel/debug/kdb') diff --git a/kernel/debug/kdb/kdb_bp.c b/kernel/debug/kdb/kdb_bp.c index 8418c2f..70a5046 100644 --- a/kernel/debug/kdb/kdb_bp.c +++ b/kernel/debug/kdb/kdb_bp.c @@ -486,11 +486,9 @@ static int kdb_bc(int argc, const char **argv) /* * kdb_ss * - * Process the 'ss' (Single Step) and 'ssb' (Single Step to Branch) - * commands. + * Process the 'ss' (Single Step) command. * * ss - * ssb * * Parameters: * argc Argument count @@ -498,35 +496,23 @@ static int kdb_bc(int argc, const char **argv) * Outputs: * None. * Returns: - * KDB_CMD_SS[B] for success, a kdb error if failure. + * KDB_CMD_SS for success, a kdb error if failure. * Locking: * None. * Remarks: * * Set the arch specific option to trigger a debug trap after the next * instruction. - * - * For 'ssb', set the trace flag in the debug trap handler - * after printing the current insn and return directly without - * invoking the kdb command processor, until a branch instruction - * is encountered. */ static int kdb_ss(int argc, const char **argv) { - int ssb = 0; - - ssb = (strcmp(argv[0], "ssb") == 0); if (argc != 0) return KDB_ARGCOUNT; /* * Set trace flag and go. */ KDB_STATE_SET(DOING_SS); - if (ssb) { - KDB_STATE_SET(DOING_SSB); - return KDB_CMD_SSB; - } return KDB_CMD_SS; } @@ -561,8 +547,6 @@ void __init kdb_initbptab(void) kdb_register_repeat("ss", kdb_ss, "", "Single Step", 1, KDB_REPEAT_NO_ARGS); - kdb_register_repeat("ssb", kdb_ss, "", - "Single step to branch/call", 0, KDB_REPEAT_NO_ARGS); /* * Architecture dependent initialization. */ diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c index d04a6ce..328d18e 100644 --- a/kernel/debug/kdb/kdb_debugger.c +++ b/kernel/debug/kdb/kdb_debugger.c @@ -114,7 +114,6 @@ int kdb_stub(struct kgdb_state *ks) /* Remove any breakpoints as needed by kdb and clear single step */ kdb_bp_remove(); KDB_STATE_CLEAR(DOING_SS); - KDB_STATE_CLEAR(DOING_SSB); KDB_STATE_SET(PAGER); /* zero out any offline cpu data */ for_each_present_cpu(i) { diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 496f596..00eb8f7 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -1128,7 +1128,6 @@ void kdb_set_current_task(struct task_struct *p) * KDB_CMD_GO User typed 'go'. * KDB_CMD_CPU User switched to another cpu. * KDB_CMD_SS Single step. - * KDB_CMD_SSB Single step until branch. */ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs, kdb_dbtrap_t db_result) @@ -1167,14 +1166,6 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs, kdb_printf("due to Debug @ " kdb_machreg_fmt "\n", instruction_pointer(regs)); break; - case KDB_DB_SSB: - /* - * In the midst of ssb command. Just return. - */ - KDB_DEBUG_STATE("kdb_local 3", reason); - return KDB_CMD_SSB; /* Continue with SSB command */ - - break; case KDB_DB_SS: break; case KDB_DB_SSBPT: @@ -1297,7 +1288,6 @@ do_full_getstr: if (diag == KDB_CMD_GO || diag == KDB_CMD_CPU || diag == KDB_CMD_SS - || diag == KDB_CMD_SSB || diag == KDB_CMD_KGDB) break; @@ -1384,12 +1374,6 @@ int kdb_main_loop(kdb_reason_t reason, kdb_reason_t reason2, int error, break; } - if (result == KDB_CMD_SSB) { - KDB_STATE_SET(DOING_SS); - KDB_STATE_SET(DOING_SSB); - break; - } - if (result == KDB_CMD_KGDB) { if (!KDB_STATE(DOING_KGDB)) kdb_printf("Entering please attach debugger " diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h index 392ec6a..7afd3c8 100644 --- a/kernel/debug/kdb/kdb_private.h +++ b/kernel/debug/kdb/kdb_private.h @@ -19,7 +19,6 @@ #define KDB_CMD_GO (-1001) #define KDB_CMD_CPU (-1002) #define KDB_CMD_SS (-1003) -#define KDB_CMD_SSB (-1004) #define KDB_CMD_KGDB (-1005) /* Internal debug flags */ @@ -125,8 +124,6 @@ extern int kdb_state; * kdb control */ #define KDB_STATE_HOLD_CPU 0x00000010 /* Hold this cpu inside kdb */ #define KDB_STATE_DOING_SS 0x00000020 /* Doing ss command */ -#define KDB_STATE_DOING_SSB 0x00000040 /* Doing ssb command, - * DOING_SS is also set */ #define KDB_STATE_SSBPT 0x00000080 /* Install breakpoint * after one ss, independent of * DOING_SS */ @@ -191,7 +188,6 @@ extern void kdb_bp_remove(void); typedef enum { KDB_DB_BPT, /* Breakpoint */ KDB_DB_SS, /* Single-step trap */ - KDB_DB_SSB, /* Single step to branch */ KDB_DB_SSBPT, /* Single step over breakpoint */ KDB_DB_NOBPT /* Spurious breakpoint */ } kdb_dbtrap_t; -- cgit v1.1