malloc crash
Ken Brown
kbrown@cornell.edu
Tue Oct 26 14:32:07 GMT 2021
On 10/26/2021 5:24 AM, Corinna Vinschen wrote:
> On Oct 25 18:02, Ken Brown wrote:
>> Or does the fifo_reader thread call a malloc function before the main thread
>> has called malloc_init()? This would presumably cause __malloc_lock() to
>> fail, but there's no error check.
>
> That sounds more likely. In theory this shouldn't have much influence,
> though. First of all, all fixup calls are running in a single thread,
> so there's no serialization required(*), and the malloc_init call
> doesn't set up the malloc arena, it just initializes the muto and checks
> for user space provided malloc calls, which is not a problem in this
> scenario.
>
> (*) unless multiple threads are started during fixup and some of these
> threads mallocate memory again...
>
> Ken, is there a chance to tweak the fifo code to stop creating
> threads from inside fixup, and to defer the thread start to the first
> call in the process actually relying on the thread being started?
I can't think of any way to do that. The thread is listening for various events
that cause it to take action, so it has to always be running. But I can
probably tweak the code so that the thread doesn't have to call malloc early on.
It might take a while to get this right, and the bug has existed ever since I
overhauled the fifo code. So I don't think you have to hold up releasing 3.3.0
while I work on this.
Ken
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