Use-after-clear bug in adc_lld.c

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Use-after-clear bug in adc_lld.c

Postby bunnie » Fri Apr 01, 2016 12:19 pm

Hi, I found a use-after-clear bug in adc_lld.c for the Kinetis branch.

Basically, in the adc ISR code, _adc_isr_full_code() is called and then ADCD1.grpp->circular is referenced.

However, adc_isr_full_code() will set ADCD1.grpp to NULL at the end of a conversion, causing the pointer dereference to yield bogus results. In my case, I was trying to do a single conversion but the bogus dereference would set the system into circular conversion mode, causing the subsequent conversion's ISR to enter with a NULL grpp structure, leading to all kinds of sadness.

Swapping the order of operations so the dereference happens prior to the isr callback seems to fix the problem for me.
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Re: Use-after-clear bug in adc_lld.c

Postby utzig » Fri Apr 01, 2016 2:22 pm


We are moving the Kinetis repo to Github ( Basically what reminds is removing the port from the main SVN repo. I don't mind applying this patch myself but in case you use Github and wanna send a pull request or want me to add a signed-off-by just ask.

Fabio Utzig

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