Hi Bin,
On Wed, Sep 9, 2015 at 1:14 AM, Bin Meng bmeng.cn@gmail.com wrote:
Hi Joe,
On Wed, Sep 9, 2015 at 11:19 AM, Bin Meng bmeng.cn@gmail.com wrote:
Hi Joe,
On Wed, Sep 9, 2015 at 1:23 AM, Joe Hershberger joe.hershberger@gmail.com wrote:
Hi Bin,
On Tue, Sep 8, 2015 at 11:24 AM, Bin Meng bmeng.cn@gmail.com wrote:
Hi Joe,
On Wed, Sep 9, 2015 at 12:01 AM, Joe Hershberger joe.hershberger@gmail.com wrote:
Hi Bin,
On Tue, Sep 8, 2015 at 10:44 AM, Bin Meng bmeng.cn@gmail.com wrote:
Hi Joe,
On Tue, Sep 8, 2015 at 11:32 PM, Joe Hershberger joe.hershberger@gmail.com wrote: > Hi Bin, > > On Sat, Sep 5, 2015 at 9:38 PM, Bin Meng bmeng.cn@gmail.com wrote: >> In eth_init(), eth_get_dev() can return NULL. We should do sanity >> test on eth dev before calling its start function. >> >> Signed-off-by: Bin Meng bmeng.cn@gmail.com >> --- >> >> net/eth.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/net/eth.c b/net/eth.c >> index 26520d3..6ec3a86 100644 >> --- a/net/eth.c >> +++ b/net/eth.c >> @@ -370,6 +370,10 @@ int eth_init(void) >> eth_try_another(0); >> /* This will ensure the new "current" attempted to probe */ >> current = eth_get_dev(); >> + if (!current) { >> + printf("No ethernet found.\n"); >> + break; >> + } > > I'm not sure I get the point of this. We already have a check above... > > current = eth_get_dev(); > if (!current) { > printf("No ethernet found.\n"); > return -ENODEV; > } >
But this does not help. Each time eth_get_dev() is called, current can be NULL as driver's probe can fail.
If that's the issue you are hitting it seems like you should attempt to skip the device instead of printing the message. It doesn't make sense to me to move to the next device and then print that there is no Ethernet.
Do you mean we should not printf("No ethernet found.\n") and just break here?
I think you shouldn't break, but rather should have an if check around the top half of the loop. I.e.:
diff --git a/net/eth.c b/net/eth.c index d3ec8d6..78ffb5f 100644 --- a/net/eth.c +++ b/net/eth.c @@ -343,23 +343,27 @@ int eth_init(void)
old_current = current; do {
debug("Trying %s\n", current->name);if (device_active(current)) {ret = eth_get_ops(current)->start(current);if (ret >= 0) {struct eth_device_priv *priv =current->uclass_priv;priv->state = ETH_STATE_ACTIVE;return 0;
if (current) {debug("Trying %s\n", current->name);if (device_active(current)) {ret = eth_get_ops(current)->start(current);if (ret >= 0) {struct eth_device_priv *priv =current->uclass_priv;priv->state = ETH_STATE_ACTIVE;return 0;}} else {ret = eth_errno; }debug("FAIL\n"); } else {
ret = eth_errno;
debug("PROBE FAIL\n"); }
debug("FAIL\n");/* * If ethrotate is enabled, this will change "current", * otherwise we will drop out of this while loop immediately
Note that I have not tested this, it's just what I'm thinking is more appropriate.
If it fails, U-Boot just crashes as there is a NULL pointer. I am not sure if test case is able to handle this?
I think it's good to have the a test that hits your scenario. The bug fix will prevent the crash, so it's not like we expect it to crash, but it will lock down the desired behavior for this condition.
I am afraid creating a test case to cover this scenario is not that easy. Checking function return value does not bring any harm. It makes our codes safer. In fact, during further debug today, I found another two places which does not check device_probe() return value. And it is indeed these two places which causes the subsequent failure here.
OK, I've found a way in the DM test codes to trigger this fault, but unfortunately by creating this test case I've found another potential issue. I will send a v2 patch for all of these.
Thanks for looking into this.
Cheers, -Joe