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mem: exclude unused memory from core dump

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Currently, even though memory is mapped with PROT_NONE, this does not
cause it to be excluded from core dumps. This is counter-productive,
because in a lot of cases, this memory will go unused (e.g. when the
memory subsystem preallocates VA space but hasn't yet mapped physical
pages into it).

Use `madvise()` call with MADV_DONTDUMP/MADV_NOCORE to exclude the
unused memory from being dumped.

Signed-off-by: Li Feng <fengli@smartx.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
This commit is contained in:
Li Feng 2020-04-24 21:19:05 +08:00 committed by David Marchand
parent 76e91e3f14
commit d72e4042c5
2 changed files with 18 additions and 0 deletions
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15
lib/librte_eal/common/eal_common_memory.c
View File

@ -40,6 +40,14 @@
static void *next_baseaddr; static void *next_baseaddr;
static uint64_t system_page_sz; static uint64_t system_page_sz;
#ifdef RTE_EXEC_ENV_LINUX
#define RTE_DONTDUMP MADV_DONTDUMP
#elif RTE_EXEC_ENV_FREEBSD
#define RTE_DONTDUMP MADV_NOCORE
#else
#error "madvise doesn't support this OS"
#endif
#define MAX_MMAP_WITH_DEFINED_ADDR_TRIES 5 #define MAX_MMAP_WITH_DEFINED_ADDR_TRIES 5
void * void *
eal_get_virtual_area(void *requested_addr, size_t *size, eal_get_virtual_area(void *requested_addr, size_t *size,
@ -179,6 +187,13 @@ eal_get_virtual_area(void *requested_addr, size_t *size,
munmap(aligned_end, after_len); munmap(aligned_end, after_len);
} }
if (!unmap) {
/* Exclude these pages from a core dump. */
if (madvise(aligned_addr, *size, RTE_DONTDUMP) != 0)
RTE_LOG(DEBUG, EAL, "madvise failed: %s\n",
strerror(errno));
}
return aligned_addr; return aligned_addr;
} }

3
lib/librte_eal/linux/eal_memalloc.c
View File

@ -687,6 +687,9 @@ free_seg(struct rte_memseg *ms, struct hugepage_info *hi,
return -1; return -1;
} }
if (madvise(ms->addr, ms->len, MADV_DONTDUMP) != 0)
RTE_LOG(DEBUG, EAL, "madvise failed: %s\n", strerror(errno));
exit_early = false; exit_early = false;
/* if we're using anonymous hugepages, nothing to be done */ /* if we're using anonymous hugepages, nothing to be done */