[LU-8819] lprocfs_alloc_stats() Segmentation fault (core dumped)

• Type: Bug
• Resolution: Unresolved
• Priority: Minor
• Affects Version/s: Lustre 2.8.0
• Labels: lprocfs
• Environment: lustre 2.8.0 centos7 kernel-3.10.0_3.10.0_327.3.1.el7_lustre.x86_64-1.x86_64

Epic/Theme

Lustre-2.8.0

• Severity: 4

Epic

interoperability

• Project: Test Infrastructure
• Assignee: Lai Siyao
• Reporter: ShijunDeng (Inactive)

Description

In lustre/obdclass/lprocfs_status.c ,and in the function "lprocfs_alloc_stats",
when alloc percpu pointers for all possible cpu slots,the corresponding code:
LIBCFS_ALLOC(stats, offsetof(typeof(*stats), ls_percpu[num_entry]));
In fact ,this code didn't alloc space for its member struct lprocfs_counter lp_cntr[0],
but in other operations like funcion：
lprocfs_counter_init which call lprocfs_stats_counter_get
the code in fuction lprocfs_stats_counter_get such as
stats->ls_percpu[cpuid]->lp_cntr[index]
may access memory that not belong to var stats itself,
it's not safe and may lead to Segmentation fault.especially when there is not enough memory.