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authorVincent Whitchurch <vincent.whitchurch@axis.com>2022-08-18 14:50:26 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-08-30 15:31:53 +0300
commit56c14fb4086b2de6921dd70251b19b364b909ea1 (patch)
tree796ed82646c2af26914f7027782cb3e2b02b0cdc /drivers/tty
parent846651eca073e2e02e37490a4a52752415d84781 (diff)
downloadlinux-56c14fb4086b2de6921dd70251b19b364b909ea1.tar.xz
tty: Fix lookahead_buf crash with serdev
Do not follow a NULL pointer if the tty_port_client_operations does not implement the ->lookahead_buf() callback, which is the case with serdev's ttyport. Reported-by: Hans de Goede <hdegoede@redhat.com> Fixes: 6bb6fa6908ebd3 ("tty: Implement lookahead to process XON/XOFF timely") Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Link: https://lore.kernel.org/r/20220818115026.2237893-1-vincent.whitchurch@axis.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/tty_buffer.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 9fdecc795b6b..5e287dedce01 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -470,7 +470,6 @@ static void lookahead_bufs(struct tty_port *port, struct tty_buffer *head)
while (head) {
struct tty_buffer *next;
- unsigned char *p, *f = NULL;
unsigned int count;
/*
@@ -489,11 +488,16 @@ static void lookahead_bufs(struct tty_port *port, struct tty_buffer *head)
continue;
}
- p = char_buf_ptr(head, head->lookahead);
- if (~head->flags & TTYB_NORMAL)
- f = flag_buf_ptr(head, head->lookahead);
+ if (port->client_ops->lookahead_buf) {
+ unsigned char *p, *f = NULL;
+
+ p = char_buf_ptr(head, head->lookahead);
+ if (~head->flags & TTYB_NORMAL)
+ f = flag_buf_ptr(head, head->lookahead);
+
+ port->client_ops->lookahead_buf(port, p, f, count);
+ }
- port->client_ops->lookahead_buf(port, p, f, count);
head->lookahead += count;
}
}