diff options
| author | John Ogness <john.ogness@linutronix.de> | 2023-07-17 21:52:01 +0206 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-02-21 13:50:09 +0100 |
| commit | 8255da6dd443f8679626a71d7aba1d0500c54a6f (patch) | |
| tree | 5bddc7f2585cb8a9e55104d1227ee5a75bb6997b /kernel/debug | |
| parent | 95036d4c01167568166108d42c2b0e9f8dbd7d2b (diff) | |
kdb: Do not assume write() callback available
commit 6d3e0d8cc63221dec670d0ee92ac57961581e975 upstream.
It is allowed for consoles to not provide a write() callback. For
example ttynull does this.
Check if a write() callback is available before using it.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230717194607.145135-2-john.ogness@linutronix.de
Cc: Brian Norris <briannorris@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/debug')
| -rw-r--r-- | kernel/debug/kdb/kdb_io.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index d545abe08087..95bccbe3495c 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -576,6 +576,8 @@ static void kdb_msg_write(const char *msg, int msg_len) continue; if (c == dbg_io_ops->cons) continue; + if (!c->write) + continue; /* * Set oops_in_progress to encourage the console drivers to * disregard their internal spin locks: in the current calling |