| Message ID | 20250326123047.2797946-1-manjunatha.venkatesh@nxp.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v6] i3c: Add NULL pointer check in i3c_master_queue_ibi() | expand |
On Wed, 26 Mar 2025 18:00:46 +0530, Manjunatha Venkatesh wrote: > The I3C master driver may receive an IBI from a target device that has not > been probed yet. In such cases, the master calls `i3c_master_queue_ibi()` > to queue an IBI work task, leading to "Unable to handle kernel read from > unreadable memory" and resulting in a kernel panic. > > Typical IBI handling flow: > 1. The I3C master scans target devices and probes their respective drivers. > 2. The target device driver calls `i3c_device_request_ibi()` to enable IBI > and assigns `dev->ibi = ibi`. > 3. The I3C master receives an IBI from the target device and calls > `i3c_master_queue_ibi()` to queue the target device driver’s IBI > handler task. > > [...] Applied, thanks! [1/1] i3c: Add NULL pointer check in i3c_master_queue_ibi() https://git.kernel.org/abelloni/c/bd496a44f041 Best regards,
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c index d5dc4180afbc..c65006aa0684 100644 --- a/drivers/i3c/master.c +++ b/drivers/i3c/master.c @@ -2561,6 +2561,9 @@ static void i3c_master_unregister_i3c_devs(struct i3c_master_controller *master) */ void i3c_master_queue_ibi(struct i3c_dev_desc *dev, struct i3c_ibi_slot *slot) { + if (!dev->ibi || !slot) + return; + atomic_inc(&dev->ibi->pending_ibis); queue_work(dev->ibi->wq, &slot->work); }
The I3C master driver may receive an IBI from a target device that has not been probed yet. In such cases, the master calls `i3c_master_queue_ibi()` to queue an IBI work task, leading to "Unable to handle kernel read from unreadable memory" and resulting in a kernel panic. Typical IBI handling flow: 1. The I3C master scans target devices and probes their respective drivers. 2. The target device driver calls `i3c_device_request_ibi()` to enable IBI and assigns `dev->ibi = ibi`. 3. The I3C master receives an IBI from the target device and calls `i3c_master_queue_ibi()` to queue the target device driver’s IBI handler task. However, since target device events are asynchronous to the I3C probe sequence, step 3 may occur before step 2, causing `dev->ibi` to be `NULL`, leading to a kernel panic. Add a NULL pointer check in `i3c_master_queue_ibi()` to prevent accessing an uninitialized `dev->ibi`, ensuring stability. Fixes: 3a379bbcea0af ("i3c: Add core I3C infrastructure") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/Z9gjGYudiYyl3bSe@lizhi-Precision-Tower-5810/ Signed-off-by: Manjunatha Venkatesh <manjunatha.venkatesh@nxp.com> --- Changes since v5: - Updated subject and commit message with some more information. drivers/i3c/master.c | 3 +++ 1 file changed, 3 insertions(+)