Some uart drivers specify a rs485_config() function and then decide later
to disable RS485 support for some reason (e.g. imx and ar933).
In these cases userspace may be able to activate RS485 via TIOCSRS485
nevertheless, since in uart_set_rs485_config() an existing rs485_config()
function indicates that RS485 is supported.
Make sure that this is not longer possible by checking the uarts
rs485_supported.flags instead and bailing out if SER_RS485_ENABLED is not
set.
Furthermore instead of returning an empty structure return -ENOTTY if the
RS485 configuration is requested via TIOCGRS485 but RS485 is not supported.
This has a small impact on userspace visibility but it is consistent with
the -ENOTTY error for TIOCGRS485.
Fixes: e849145e1fdd ("serial: ar933x: Fill in rs485_supported")
Fixes: 55e18c6b6d42 ("serial: imx: Remove serial_rs485 sanitization")
Cc: Shawn Guo <shawnguo(a)kernel.org>
Cc: Sascha Hauer <s.hauer(a)pengutronix.de>
Cc: stable(a)vger.kernel.org
Signed-off-by: Lino Sanfilippo <l.sanfilippo(a)kunbus.com>
---
drivers/tty/serial/serial_core.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 4eae1406cb6c..661074ab8edb 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1448,6 +1448,9 @@ static int uart_get_rs485_config(struct uart_port *port,
unsigned long flags;
struct serial_rs485 aux;
+ if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
+ return -ENOTTY;
+
uart_port_lock_irqsave(port, &flags);
aux = port->rs485;
uart_port_unlock_irqrestore(port, flags);
@@ -1465,7 +1468,7 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
int ret;
unsigned long flags;
- if (!port->rs485_config)
+ if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
return -ENOTTY;
if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
--
2.42.0
mas_preallocate() defaults to requesting 1 node for preallocation and then
,depending on the type of store, will update the request variable. There
isn't a check for a slot store type, so slot stores are preallocating the
default 1 node. Slot stores do not require any additional nodes, so add a
check for the slot store case that will bypass node_count_gfp(). Update
the tests to reflect that slot stores do not require allocations.
User visible effects of this bug include increased memory usage from the
unneeded node that was allocated.
Fixes: 0b8bb544b1a7 ("maple_tree: update mas_preallocate() testing")
Cc: <stable(a)vger.kernel.org> # 6.6+
Signed-off-by: Sidhartha Kumar <sidhartha.kumar(a)oracle.com>
---
v1->v2:
fix coding style per Matthew and Andrew
use wr_mas->node_end to fix build error
lib/maple_tree.c | 11 +++++++++++
tools/testing/radix-tree/maple.c | 2 +-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index bb24d84a4922f..684689457d77f 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5501,6 +5501,17 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp)
mas_wr_end_piv(&wr_mas);
node_size = mas_wr_new_end(&wr_mas);
+
+ /* Slot store, does not require additional nodes */
+ if (node_size == wr_mas.node_end) {
+ /* reuse node */
+ if (!mt_in_rcu(mas->tree))
+ return 0;
+ /* shifting boundary */
+ if (wr_mas.offset_end - mas->offset == 1)
+ return 0;
+ }
+
if (node_size >= mt_slots[wr_mas.type]) {
/* Split, worst case for now. */
request = 1 + mas_mt_height(mas) * 2;
diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c
index e5da1cad70baf..76a8990bb14e8 100644
--- a/tools/testing/radix-tree/maple.c
+++ b/tools/testing/radix-tree/maple.c
@@ -35538,7 +35538,7 @@ static noinline void __init check_prealloc(struct maple_tree *mt)
MT_BUG_ON(mt, mas_preallocate(&mas, ptr, GFP_KERNEL) != 0);
allocated = mas_allocated(&mas);
height = mas_mt_height(&mas);
- MT_BUG_ON(mt, allocated != 1);
+ MT_BUG_ON(mt, allocated != 0);
mas_store_prealloc(&mas, ptr);
MT_BUG_ON(mt, mas_allocated(&mas) != 0);
--
2.42.0
The quilt patch titled
Subject: maple_tree: do not preallocate nodes for slot stores
has been removed from the -mm tree. Its filename was
maple_tree-do-not-preallocate-nodes-for-slot-stores.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
From: Sidhartha Kumar <sidhartha.kumar(a)oracle.com>
Subject: maple_tree: do not preallocate nodes for slot stores
Date: Tue, 12 Dec 2023 11:46:40 -0800
mas_preallocate() defaults to requesting 1 node for preallocation and then
,depending on the type of store, will update the request variable. There
isn't a check for a slot store type, so slot stores are preallocating the
default 1 node. Slot stores do not require any additional nodes, so add a
check for the slot store case that will bypass node_count_gfp(). Update
the tests to reflect that slot stores do not require allocations.
User visible effects of this bug include increased memory usage from the
unneeded node that was allocated.
Link: https://lkml.kernel.org/r/20231212194640.217966-1-sidhartha.kumar@oracle.com
Fixes: 0b8bb544b1a7 ("maple_tree: update mas_preallocate() testing")
Signed-off-by: Sidhartha Kumar <sidhartha.kumar(a)oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett(a)oracle.com>
Cc: Matthew Wilcox (Oracle) <willy(a)infradead.org>
Cc: Peng Zhang <zhangpeng.00(a)bytedance.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
lib/maple_tree.c | 6 ++++++
tools/testing/radix-tree/maple.c | 2 +-
2 files changed, 7 insertions(+), 1 deletion(-)
--- a/lib/maple_tree.c~maple_tree-do-not-preallocate-nodes-for-slot-stores
+++ a/lib/maple_tree.c
@@ -5501,6 +5501,12 @@ int mas_preallocate(struct ma_state *mas
mas_wr_end_piv(&wr_mas);
node_size = mas_wr_new_end(&wr_mas);
+
+ /* Slot store, does not require additional nodes */
+ if ((node_size == mas->end) && ((!mt_in_rcu(mas->tree))
+ || (wr_mas.offset_end - mas->offset == 1)))
+ return 0;
+
if (node_size >= mt_slots[wr_mas.type]) {
/* Split, worst case for now. */
request = 1 + mas_mt_height(mas) * 2;
--- a/tools/testing/radix-tree/maple.c~maple_tree-do-not-preallocate-nodes-for-slot-stores
+++ a/tools/testing/radix-tree/maple.c
@@ -35538,7 +35538,7 @@ static noinline void __init check_preall
MT_BUG_ON(mt, mas_preallocate(&mas, ptr, GFP_KERNEL) != 0);
allocated = mas_allocated(&mas);
height = mas_mt_height(&mas);
- MT_BUG_ON(mt, allocated != 1);
+ MT_BUG_ON(mt, allocated != 0);
mas_store_prealloc(&mas, ptr);
MT_BUG_ON(mt, mas_allocated(&mas) != 0);
_
Patches currently in -mm which might be from sidhartha.kumar(a)oracle.com are