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author | John Ogness <john.ogness@linutronix.de> | 2023-07-17 22:46:01 +0300 |
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committer | Petr Mladek <pmladek@suse.com> | 2023-07-20 14:06:22 +0300 |
commit | 6d3e0d8cc63221dec670d0ee92ac57961581e975 (patch) | |
tree | 73b926b088fb8df780fb73a7828c6c984bb76bcc | |
parent | 7ec85f3e089aa423a69559bf4555b6218b5a2ef7 (diff) | |
download | linux-6d3e0d8cc63221dec670d0ee92ac57961581e975.tar.xz |
kdb: Do not assume write() callback available
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
-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 5c7e9ba7cd6b..e9139dfc1f0a 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 |