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[v2,11/11] i3c: master: svc: fix possible assignment of the same address to two devices

Message ID 20240813-i3c_fix-v2-11-68fe4a050188@nxp.com (mailing list archive)
State Superseded
Headers show
Series i3c: master: some fix and improvemnt for hotjoin | expand

Commit Message

Frank Li Aug. 13, 2024, 3:15 p.m. UTC 
svc_i3c_master_do_daa() {
    ...
    for (i = 0; i < dev_nb; i++) {
        ret = i3c_master_add_i3c_dev_locked(m, addrs[i]);
        if (ret)
            goto rpm_out;
    }
}

If two devices (A and B) are detected in DAA and address 0xa is assigned to
device A and 0xb to device B, a failure in i3c_master_add_i3c_dev_locked()
for device A (addr: 0xa) could prevent device B (addr: 0xb) from being
registered on the bus. The I3C stack might still consider 0xb a free
address. If a subsequent Hotjoin occurs, 0xb might be assigned to Device A,
causing both devices A and B to use the same address 0xb, violating the I3C
specification.

The return value for i3c_master_add_i3c_dev_locked() should not be checked
because subsequent steps will scan the entire I3C bus, independent of
whether i3c_master_add_i3c_dev_locked() returns success.

If device A registration fails, there is still a chance to register device
B. i3c_master_add_i3c_dev_locked() can reset DAA if a failure occurs while
retrieving device information.

Cc: stable@kernel.org
Fixes: 317bacf960a4 ("i3c: master: add enable(disable) hot join in sys entry")
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/i3c/master/svc-i3c-master.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)
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Patch

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index 0de95f406c95b..f47e5f4af68c9 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -1041,11 +1041,8 @@  static int svc_i3c_master_do_daa(struct i3c_master_controller *m)
 		goto rpm_out;
 
 	/* Register all devices who participated to the core */
-	for (i = 0; i < dev_nb; i++) {
-		ret = i3c_master_add_i3c_dev_locked(m, addrs[i]);
-		if (ret)
-			goto rpm_out;
-	}
+	for (i = 0; i < dev_nb; i++)
+		i3c_master_add_i3c_dev_locked(m, addrs[i]);
 
 	/* Configure IBI auto-rules */
 	ret = svc_i3c_update_ibirules(master);