On 27-Nov-18 10:38 AM, Burakov, Anatoly wrote:
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.
Also, it might be useful to apply this commit and check if it still happens:
71aae4b421da9b741d1fb73a190a9facfec555b9
http://patches.dpdk.org/patch/48080/
--
Thanks,
Anatoly
