[dpdk-dev] [RFC] mem_debug add more log
Stephen Hemminger
stephen at networkplumber.org
Fri Dec 18 19:54:24 CET 2020
On Fri, 18 Dec 2020 14:21:09 -0500
Peng Zhihong <zhihongx.peng at intel.com> wrote:
> 1. The debugging log in current DPDK RTE_MALLOC_DEBUG mode is insufficient,
> which makes it difficult to locate the issues, such as:
> a) When a memeory overlflow occur in rte_free, there is a little log
> information. Even if abort here, we can find which API is core
> dumped but we still need to read the source code to find out where
> the requested memory is overflowed.
> b) Current DPDK can NOT find that the overflow if the memory has been
> used and not released.
> c) If there are two pieces of continuous memory, when the first block
> is not released and an overflow is occured and also the second block
> of memory is covered, a memory overflow will be detected once the second
> block of memory is released. However, current DPDK can not find the
> correct point of memory overflow. It only detect the memory overflow
> of the second block but should dedect the one of first block.
> ----------------------------------------------------------------------------------
> | header cookie | data1 | trailer cookie | header cookie | data2 |trailer cookie |
> ----------------------------------------------------------------------------------
> 2. To fix above issues, we can store the requested information When DPDK
> request memory. Including the requested address and requested momory's
> file, function and numbers of rows and then put it into a list.
> -------------------- ---------------------- ----------------------
> | struct list_head |---->| struct malloc_info |---->| struct malloc_info |
> -------------------- ---------------------- ----------------------
> The above 3 problems can be solved through this implementation:
> a) If there is a memory overflow in rte_free, you can traverse the
> list to find the information of overflow memory and print the
> overflow memory information. like this:
> code:
> 37 char *p = rte_zmalloc(NULL, 64, 0);
> 38 memset(p, 0, 65);
> 39 rte_free(p);
> 40 //rte_malloc_validate_all_memory();
> memory error:
> EAL: Error: Invalid memory
> malloc memory address 0x17ff2c340 overflow in \
> file:../examples/helloworld/main.c function:main line:37
> b)c) Provide a interface to check all memory overflow in function
> rte_malloc_validate_all_memory, this function will check all
> memory on the list. Call this funcation manually at the exit
> point of business logic, we can find all overflow points in time.
>
> Signed-off-by: Peng Zhihong <zhihongx.peng at intel.com>
Good concept, but doesn't this add significant overhead?
Maybe we could make rte_malloc work with existing address sanitizer infrastructure
in gcc/clang? That would provide faster and more immediate better diagnostic
info.
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