diff options
| author | Douglas Anderson <dianders@chromium.org> | 2018-12-04 19:38:28 -0800 |
|---|---|---|
| committer | Daniel Thompson <daniel.thompson@linaro.org> | 2018-12-30 08:31:23 +0000 |
| commit | 162bc7f5afd75b72acbe3c5f3488ef7e64a3fe36 (patch) | |
| tree | 28a6c66c667177ad20271d85d332f0e3831b955f | |
| parent | 87b095928584da7d5cb3149016f00b0b139c2292 (diff) | |
| download | linux-162bc7f5afd75b72acbe3c5f3488ef7e64a3fe36.tar.bz2 | |
kdb: Don't back trace on a cpu that didn't round up
If you have a CPU that fails to round up and then run 'btc' you'll end
up crashing in kdb becaue we dereferenced NULL. Let's add a check.
It's wise to also set the task to NULL when leaving the debugger so
that if we fail to round up on a later entry into the debugger we
won't backtrace a stale task.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
| -rw-r--r-- | kernel/debug/debug_core.c | 4 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_bt.c | 11 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_debugger.c | 7 |
3 files changed, 14 insertions, 8 deletions
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 1fb8b239e567..5cc608de6883 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -592,6 +592,8 @@ return_normal: arch_kgdb_ops.correct_hw_break(); if (trace_on) tracing_on(); + kgdb_info[cpu].debuggerinfo = NULL; + kgdb_info[cpu].task = NULL; kgdb_info[cpu].exception_state &= ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); kgdb_info[cpu].enter_kgdb--; @@ -724,6 +726,8 @@ kgdb_restore: if (trace_on) tracing_on(); + kgdb_info[cpu].debuggerinfo = NULL; + kgdb_info[cpu].task = NULL; kgdb_info[cpu].exception_state &= ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); kgdb_info[cpu].enter_kgdb--; diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c index 7921ae4fca8d..7e2379aa0a1e 100644 --- a/kernel/debug/kdb/kdb_bt.c +++ b/kernel/debug/kdb/kdb_bt.c @@ -186,7 +186,16 @@ kdb_bt(int argc, const char **argv) kdb_printf("btc: cpu status: "); kdb_parse("cpu\n"); for_each_online_cpu(cpu) { - sprintf(buf, "btt 0x%px\n", KDB_TSK(cpu)); + void *kdb_tsk = KDB_TSK(cpu); + + /* If a CPU failed to round up we could be here */ + if (!kdb_tsk) { + kdb_printf("WARNING: no task for cpu %ld\n", + cpu); + continue; + } + + sprintf(buf, "btt 0x%px\n", kdb_tsk); kdb_parse(buf); touch_nmi_watchdog(); } diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c index 15e1a7af5dd0..53a0df6e4d92 100644 --- a/kernel/debug/kdb/kdb_debugger.c +++ b/kernel/debug/kdb/kdb_debugger.c @@ -118,13 +118,6 @@ int kdb_stub(struct kgdb_state *ks) kdb_bp_remove(); KDB_STATE_CLEAR(DOING_SS); KDB_STATE_SET(PAGER); - /* zero out any offline cpu data */ - for_each_present_cpu(i) { - if (!cpu_online(i)) { - kgdb_info[i].debuggerinfo = NULL; - kgdb_info[i].task = NULL; - } - } if (ks->err_code == DIE_OOPS || reason == KDB_REASON_OOPS) { ks->pass_exception = 1; KDB_FLAG_SET(CATASTROPHIC); |