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Commit bdef6fc5 authored by Juergen Gross's avatar Juergen Gross Committed by Greg Kroah-Hartman
Browse files

tty: hvc: replace BUG_ON() with negative return value 



commit e679004dec37566f658a255157d3aed9d762a2b7 upstream.

Xen frontends shouldn't BUG() in case of illegal data received from
their backends. So replace the BUG_ON()s when reading illegal data from
the ring page with negative return values.

Reviewed-by: default avatarJan Beulich <jbeulich@suse.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20210707091045.460-1-jgross@suse.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e4e01b0e

drivers/tty/hvc/hvc_xen.c

+14 −3
Original line number Diff line number Diff line
@@ -86,7 +86,11 @@ static int __write_console(struct xencons_info *xencons, 
	cons = intf->out_cons;

	prod = intf->out_prod;

	mb();			/* update queue values before going on */

	BUG_ON((prod - cons) > sizeof(intf->out));



	if ((prod - cons) > sizeof(intf->out)) {

		pr_err_once("xencons: Illegal ring page indices");

		return -EINVAL;

	}



	while ((sent < len) && ((prod - cons) < sizeof(intf->out)))

		intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
@@ -115,6 +119,9 @@ static int domU_write_console(uint32_t vtermno, const char *data, int len) 
	while (len) {

		int sent = __write_console(cons, data, len);



		if (sent < 0)

			return sent;



		data += sent;

		len -= sent;
@@ -138,7 +145,11 @@ static int domU_read_console(uint32_t vtermno, char *buf, int len) 
	cons = intf->in_cons;

	prod = intf->in_prod;

	mb();			/* get pointers before reading ring */

	BUG_ON((prod - cons) > sizeof(intf->in));



	if ((prod - cons) > sizeof(intf->in)) {

		pr_err_once("xencons: Illegal ring page indices");

		return -EINVAL;

	}



	while (cons != prod && recv < len)

		buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];