[PATCH 3/3] i3c: master: Fix dynamic address leak when 'assigned-address' is present

Frank Li
2024-10-01T17:09:10Z

If the DTS contains 'assigned-address', a dynamic address leak occurs
during hotjoin events.

Assume a device have assigned-address 0xb.
- Device issue Hotjoin
- Call i3c_master_do_daa()
- Call driver xxx_do_daa()
- Call i3c_master_get_free_addr() to get dynamic address 0x9
- i3c_master_add_i3c_dev_locked(0x9)
- expected_dyn_addr = newdev->boardinfo->init_dyn_addr (0xb);
- i3c_master_reattach_i3c_dev(newdev(0xb), old_dyn_addr(0x9));
- if (dev->info.dyn_addr != old_dyn_addr &&
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 0xb != 0x9 -> TRUE
(!dev->boardinfo ||
^^^^^^^^^^^^^^^ -> FALSE
dev->info.dyn_addr != dev->boardinfo->init_dyn_addr)) {
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
0xb != 0xb -> FALSE
...
i3c_bus_set_addr_slot_status(&master->bus, old_dyn_addr,
I3C_ADDR_SLOT_FREE);
^^^
This will be skipped. So old_dyn_addr never free
}

- i3c_master_get_free_addr() will return increased sequence number.

Remove dev->info.dyn_addr != dev->boardinfo->init_dyn_addr condition check.
dev->info.dyn_addr should be checked before calling this function because
i3c_master_setnewda_locked() has already been called and the target device
has already accepted dyn_addr. It is too late to check if dyn_addr is free
in i3c_master_reattach_i3c_dev().

Add check to ensure expected_dyn_addr is free before
i3c_master_setnewda_locked().

Fixes: cc3a392d69b6 ("i3c: master: fix for SETDASA and DAA process")
Cc: stable@kernel.org
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Change v3 to v4
- none
---
drivers/i3c/master.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index a56cb281e6b6d..eae7449f0dacb 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -1556,16 +1556,9 @@ static int i3c_master_reattach_i3c_dev(struct i3c_dev_desc *dev,
u8 old_dyn_addr)
{
struct i3c_master_controller *master = i3c_dev_get_master(dev);
- enum i3c_addr_slot_status status;
int ret;

- if (dev->info.dyn_addr != old_dyn_addr &&
- (!dev->boardinfo ||
- dev->info.dyn_addr != dev->boardinfo->init_dyn_addr)) {
- status = i3c_bus_get_addr_slot_status(&master->bus,
- dev->info.dyn_addr);
- if (status != I3C_ADDR_SLOT_FREE)
- return -EBUSY;
+ if (dev->info.dyn_addr != old_dyn_addr) {
i3c_bus_set_addr_slot_status(&master->bus,
dev->info.dyn_addr,
I3C_ADDR_SLOT_I3C_DEV);
@@ -1968,9 +1961,10 @@ static int i3c_master_bus_init(struct i3c_master_controller *master)
goto err_rstdaa;
}

+ /* Not mark as occupied until real device exist in bus */
i3c_bus_set_addr_slot_status_ext(&master->bus,
i3cboardinfo->init_dyn_addr,
- I3C_ADDR_SLOT_I3C_DEV | I3C_ADDR_SLOT_EXT_INIT);
+ I3C_ADDR_SLOT_EXT_INIT);

/*
* Only try to create/attach devices that have a static
@@ -2133,7 +2127,8 @@ int i3c_master_add_i3c_dev_locked(struct i3c_master_controller *master,
else
expected_dyn_addr = newdev->info.dyn_addr;

- if (newdev->info.dyn_addr != expected_dyn_addr) {
+ if (newdev->info.dyn_addr != expected_dyn_addr &&
+ i3c_bus_get_addr_slot_status(&master->bus, expected_dyn_addr) == I3C_ADDR_SLOT_FREE) {
/*
* Try to apply the expected dynamic address. If it fails, keep
* the address assigned by the master.

--
2.34.1