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| author | Douglas Anderson <dianders@chromium.org> | 2023-08-22 13:19:46 -0700 |
|---|---|---|
| committer | Daniel Thompson <daniel.thompson@linaro.org> | 2023-10-15 18:07:50 +0100 |
| commit | dd712d3d45807db9fcae28a522deee85c1f2fde6 (patch) | |
| tree | 1ad1c32118cb9baa41194cad6760fd7b6faa0878 /kernel/debug | |
| parent | 94f6f0550c625fab1f373bb86a6669b45e9748b3 (diff) | |
| download | linux-dd712d3d45807db9fcae28a522deee85c1f2fde6.tar.gz linux-dd712d3d45807db9fcae28a522deee85c1f2fde6.tar.bz2 linux-dd712d3d45807db9fcae28a522deee85c1f2fde6.zip | |
kgdb: Flush console before entering kgdb on panic
When entering kdb/kgdb on a kernel panic, it was be observed that the
console isn't flushed before the `kdb` prompt came up. Specifically,
when using the buddy lockup detector on arm64 and running:
echo HARDLOCKUP > /sys/kernel/debug/provoke-crash/DIRECT
I could see:
[ 26.161099] lkdtm: Performing direct entry HARDLOCKUP
[ 32.499881] watchdog: Watchdog detected hard LOCKUP on cpu 6
[ 32.552865] Sending NMI from CPU 5 to CPUs 6:
[ 32.557359] NMI backtrace for cpu 6
... [backtrace for cpu 6] ...
[ 32.558353] NMI backtrace for cpu 5
... [backtrace for cpu 5] ...
[ 32.867471] Sending NMI from CPU 5 to CPUs 0-4,7:
[ 32.872321] NMI backtrace forP cpuANC: Hard LOCKUP
Entering kdb (current=..., pid 0) on processor 5 due to Keyboard Entry
[5]kdb>
As you can see, backtraces for the other CPUs start printing and get
interleaved with the kdb PANIC print.
Let's replicate the commands to flush the console in the kdb panic
entry point to avoid this.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20230822131945.1.I5b460ae8f954e4c4f628a373d6e74713c06dd26f@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Diffstat (limited to 'kernel/debug')
| -rw-r--r-- | kernel/debug/debug_core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 621037a0aa87..ce1bb2301c06 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -1006,6 +1006,9 @@ void kgdb_panic(const char *msg) if (panic_timeout) return; + debug_locks_off(); + console_flush_on_panic(CONSOLE_FLUSH_PENDING); + if (dbg_kdb_mode) kdb_printf("PANIC: %s\n", msg); |