[dpdk-dev] struct malloc_elem overrun/corruption
Burakov, Anatoly
anatoly.burakov at intel.com
Tue Nov 27 11:38:09 CET 2018
On 26-Nov-18 11:44 PM, He Huang wrote:
> Hi,
>
> I’ve been troubleshooting a possible memory allocator corruption:
> Program received signal SIGSEGV, Segmentation fault.
> [Switching to Thread 0x7fffefdf0700 (LWP 1079)]
> 0x00000000004794ee in malloc_elem_free_list_insert (elem=0x7ff82d265000) at dpdk/lib/librte_eal/common/malloc_elem.c:292
> 292 LIST_INSERT_HEAD(&elem->heap->free_head[idx], elem, free_list);
> (gdb) bt
> #0 0x00000000004794ee in malloc_elem_free_list_insert (elem=0x7ff82d265000) at dpdk/lib/librte_eal/common/malloc_elem.c:292
> #1 0x0000000000479971 in malloc_elem_free (elem=0x7ff82d265000) at dpdk/lib/librte_eal/common/malloc_elem.c:448
> #2 0x000000000047b054 in malloc_heap_free (elem=0x7ff82d265fc0) at dpdk/lib/librte_eal/common/malloc_heap.c:628
> #3 0x00000000004787f5 in rte_free (addr=0x7ff82d266000) at dpdk/lib/librte_eal/common/rte_malloc.c:32
>
> Looked like the 1st field of struct malloc_elem (i.e. the heap pointer: struct malloc_heap *heap) was corrupted. Everything else looked good:
> (gdb) p *elem
> $2 = {
> heap = 0x9e0,
> prev = 0x7ff82d254fc0,
> next = 0x7ff84ce9a000,
> free_list = {
> le_next = 0x7ff873c89000,
> le_prev = 0x7ff82bcbf018
> },
> msl = 0x7ffff7f3d07c,
> state = ELEM_FREE,
> pad = 0,
> size = 532893696
> }
> (gdb) p *elem->prev
> $3 = {
> heap = 0x7ffff7f3f67c,
> prev = 0x7ff82ce14000,
> next = 0x7ff82d265000,
> free_list = {
> le_next = 0x0,
> le_prev = 0x0
> },
> msl = 0x7ffff7f3d07c,
> state = ELEM_BUSY,
> pad = 0,
> size = 65600
> }
>
> I haven’t completely ruled out my own code had a buffer overrun and corrupted the first field of malloc_elem object yet, but I’m beginning to look at it as a possible DPDK internal corruption. The DPDK code isn’t the latest but it had malloc fixes up to commit 9554dbb50a8a22942128a0e5bcb52243a4f723ab.
>
> Ideas/suggestions greatly appreciated! BTW it’s DMA memory so I couldn’t just use malloc/free and debug with standard memory debuggers.
>
> Thanks,
> Isaac
>
Hi Isaac,
You might want to look into enabling malloc debug options.
--
Thanks,
Anatoly
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