On 03/05/2017 12:43 PM, Philippe Gerum wrote: > On 03/04/2017 03:30 AM, Josh Bowman wrote: >> Hi, >> >> I'm having a problem when trying to allocate multiple blocks using >> rt_queue_alloc(). When my client code is building a message to send to >> queue, it sometimes finds that it needs a bigger block. So it creates a new >> block via rt_queue_alloc(); copies the data from the previous block into >> the new block; and then calls rt_queue_free() on the old block. >> >> The code included here is a simplified version of this process. It >> allocates a buffer; puts some data in it; allocates a new buffer; and then >> checks to make sure the previous buffer is intact. Then it frees the >> previous buffer and loops. >> >> When I run this code, it prints: >> >> ERROR: at 7, 2: after rt_queue_alloc, checkMessage failed at loc 480 >> >> This means the buffer previously returned by rt_queue_alloc() is damaged by >> the next call to rt_queue_alloc(). I set a watch in the debugger, and it >> looks like the damage is done at line 376 of lib/alchemy/queue.c; this >> seems to indicate the heapobj_alloc() is returning a region that overlaps >> the one previously allocated. >> >> I'm running Xenomai/mercury from stable-3.0.x on x86_64, with config: >> "--with-core=mercury --enable-smp --enable-pshared --enable-registry >> --enable-debug" >> >> I build the test program with: >> >> g++ queue-2.cpp -o queue-2 -g -fno-default-inline -fno-omit-frame-pointer >> `xeno-config --skin=alchemy --cflags --no-auto-init --ldflags` >> >> Changing the realloc_count parameter causes the code to fail at different >> iterations; passing realloc_count = 3 moves the failure to the >> rt_queue_send() call. (The code runs to completion with realloc_count set >> to 1 or 2.) >> >> I've also found that if I don't call rt_queue_free() the code runs to >> completion. >> >> Let me know if there's anything I can do to help. >> > > Your test code perfectly reproduces the issue here, thanks. There is a > severe bitmap breakage, I'm on it. >
Ugly bug affecting the page bitmap of the shared heap (--enable-pshared) which caused the allocator to be terminally confused by some allocation patterns. Fixed in the stable branch: http://git.xenomai.org/xenomai-3.git/commit/?h=stable-3.0.x&id=027898e4732cb5de9b2f1e762a61661ba9421d00 Thanks. -- Philippe. _______________________________________________ Xenomai mailing list Xenomai@xenomai.org https://xenomai.org/mailman/listinfo/xenomai
