I noticed that when I did "btc <cpu>" and the CPU I passed in hadn't rounded up that I'd crash. I was going to copy the same fix from commit 162bc7f5afd7 ("kdb: Don't back trace on a cpu that didn't round up") into the "not all the CPUs" case, but decided it'd be better to clean things up a little bit. This consolidates the two code paths. It is _slightly_ wasteful in in that the checks for "cpu" being too small or being offline isn't really needed when we're iterating over all online CPUs, but that really shouldn't hurt. Better to have the same code path. While at it, eliminate at least one slightly ugly (and totally needless) recursive use of kdb_parse().
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| @@ -101,6 +101,27 @@ kdb_bt1(struct task_struct *p, unsigned long mask, bool btaprompt) · 100 unmodified lines | ||
| 101 | 101 | return 0; |
| 102 | 102 | } |
| 103 | 103 | |
| 104 | +static void | |
| 105 | +kdb_bt_cpu(unsigned long cpu) | |
| 106 | +{ | |
| 107 | + struct task_struct *kdb_tsk; | |
| 108 | + | |
| 109 | + if (cpu >= num_possible_cpus() || !cpu_online(cpu)) { | |
| 110 | + kdb_printf("WARNING: no process for cpu %ld\n", cpu); | |
| 111 | + return; | |
| 112 | + } | |
| 113 | + | |
| 114 | + /* If a CPU failed to round up we could be here */ | |
| 115 | + kdb_tsk = KDB_TSK(cpu); | |
| 116 | + if (!kdb_tsk) { | |
| 117 | + kdb_printf("WARNING: no task for cpu %ld\n", cpu); | |
| 118 | + return; | |
| 119 | + } | |
| 120 | + | |
| 121 | + kdb_set_current_task(kdb_tsk); | |
| 122 | + kdb_bt1(kdb_tsk, ~0UL, false); | |
| 123 | +} | |
| 124 | + | |
| 104 | 125 | int |
| 105 | 126 | kdb_bt(int argc, const char **argv) |
| 106 | 127 | { |
| @@ -161,7 +182,6 @@ kdb_bt(int argc, const char **argv) · 54 unmodified lines | ||
| 161 | 182 | } else if (strcmp(argv[0], "btc") == 0) { |
| 162 | 183 | unsigned long cpu = ~0; |
| 163 | 184 | struct task_struct *save_current_task = kdb_current_task; |
| 164 | − char buf[80]; | |
| 165 | 185 | if (argc > 1) |
| 166 | 186 | return KDB_ARGCOUNT; |
| 167 | 187 | if (argc == 1) { |
| @@ -169,35 +189,22 @@ kdb_bt(int argc, const char **argv) · 1 unmodified line | ||
| 169 | 189 | if (diag) |
| 170 | 190 | return diag; |
| 171 | 191 | } |
| 172 | − /* Recursive use of kdb_parse, do not use argv after | |
| 173 | − * this point */ | |
| 174 | − argv = NULL; | |
| 175 | 192 | if (cpu != ~0) { |
| 176 | − if (cpu >= num_possible_cpus() || !cpu_online(cpu)) { | |
| 177 | − kdb_printf("no process for cpu %ld\n", cpu); | |
| 178 | − return 0; | |
| 179 | − } | |
| 180 | − sprintf(buf, "btt 0x%px\n", KDB_TSK(cpu)); | |
| 181 | − kdb_parse(buf); | |
| 182 | − return 0; | |
| 183 | − } | |
| 184 | − kdb_printf("btc: cpu status: "); | |
| 185 | − kdb_parse("cpu\n"); | |
| 186 | − for_each_online_cpu(cpu) { | |
| 187 | − void *kdb_tsk = KDB_TSK(cpu); | |
| 188 | − | |
| 189 | − /* If a CPU failed to round up we could be here */ | |
| 190 | − if (!kdb_tsk) { | |
| 191 | − kdb_printf("WARNING: no task for cpu %ld\n", | |
| 192 | − cpu); | |
| 193 | − continue; | |
| 193 | + kdb_bt_cpu(cpu); | |
| 194 | + } else { | |
| 195 | + /* | |
| 196 | + * Recursive use of kdb_parse, do not use argv after | |
| 197 | + * this point. | |
| 198 | + */ | |
| 199 | + argv = NULL; | |
| 200 | + kdb_printf("btc: cpu status: "); | |
| 201 | + kdb_parse("cpu\n"); | |
| 202 | + for_each_online_cpu(cpu) { | |
| 203 | + kdb_bt_cpu(cpu); | |
| 204 | + touch_nmi_watchdog(); | |
| 194 | 205 | } |
| 195 | − | |
| 196 | − sprintf(buf, "btt 0x%px\n", kdb_tsk); | |
| 197 | − kdb_parse(buf); | |
| 198 | − touch_nmi_watchdog(); | |
| 206 | + kdb_set_current_task(save_current_task); | |
| 199 | 207 | } |
| 200 | − kdb_set_current_task(save_current_task); | |
| 201 | 208 | return 0; |
| 202 | 209 | } else { |
| 203 | 210 | if (argc) { |