diff options
| author | Sreenath Vijayan <sreenath.vijayan@sony.com> | 2024-03-13 15:52:52 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-11 14:22:52 +0200 |
| commit | 1b743485e27f3d874695434cc8103f557dfdf4b9 (patch) | |
| tree | 14b82b81d65986d60c3042316a322f6590c3cdff /drivers/tty/sysrq.c | |
| parent | 693f75b91a9171e99f84fc193e39f48e21ba4a4f (diff) | |
tty/sysrq: Replay kernel log messages on consoles via sysrq
When terminal is unresponsive, one cannot use dmesg to view
the printk ring buffer messages. Also, syslog services may be
disabled, especially on embedded systems, to check the messages
after a reboot. In this scenario, replay the messages in printk
ring buffer on consoles via sysrq by pressing sysrq+R.
The console loglevel will determine which all kernel log messages
are displayed. The messages will be displayed only when
console_trylock() succeeds. Users could repeat the sysrq key when
it fails. If the owner of console subsystem lock is stuck,
repeating the key won't work.
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Shimoyashiki Taichi <taichi.shimoyashiki@sony.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Sreenath Vijayan <sreenath.vijayan@sony.com>
Link: https://lore.kernel.org/r/cc3b9b1aae60a236c6aed1dc7b0ffa2c7cd1f183.1710220326.git.sreenath.vijayan@sony.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/sysrq.c')
| -rw-r--r-- | drivers/tty/sysrq.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c index 02217e3c916b..e5974b8239c9 100644 --- a/drivers/tty/sysrq.c +++ b/drivers/tty/sysrq.c @@ -450,6 +450,17 @@ static const struct sysrq_key_op sysrq_unrt_op = { .enable_mask = SYSRQ_ENABLE_RTNICE, }; +static void sysrq_handle_replay_logs(u8 key) +{ + console_replay_all(); +} +static struct sysrq_key_op sysrq_replay_logs_op = { + .handler = sysrq_handle_replay_logs, + .help_msg = "replay-kernel-logs(R)", + .action_msg = "Replay kernel logs on consoles", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; + /* Key Operations table and lock */ static DEFINE_SPINLOCK(sysrq_key_table_lock); @@ -519,7 +530,7 @@ static const struct sysrq_key_op *sysrq_key_table[62] = { NULL, /* O */ NULL, /* P */ NULL, /* Q */ - NULL, /* R */ + &sysrq_replay_logs_op, /* R */ NULL, /* S */ NULL, /* T */ NULL, /* U */ |