[PATCH v5 0/3] rcu: Dump memory object info if callback function is invalid

From: thunder . leizhen
Date: Thu Aug 03 2023 - 06:19:38 EST


From: Zhen Lei <thunder.leizhen@xxxxxxxxxx>

v4 --> v5:
1. Add Reviewed-by Acked-by for patch 1/3
2. Add patch 3/3:
mm: Dump the memory of slab object in kmem_dump_obj()

v3 --> v4:
1. Remove kmem_valid_obj() and convert kmem_dump_obj() to work the same way
as vmalloc_dump_obj().
2. In kernel/rcu/rcu.h
-#include <linux/mm.h>
+#include <linux/slab.h>

v2 --> v3:
1. I made statistics about the source of 'rhp'. kmem_valid_obj() accounts for
more than 97.5%, and vmalloc accounts for less than 1%. So change call
mem_dump_obj() to call kmem_dump_obj() can meet debugging requirements and
avoid the potential deadlock risk of vmalloc_dump_obj().
- mem_dump_obj(rhp);
+ if (kmem_valid_obj(rhp))
+ kmem_dump_obj(rhp);

The discussion about vmap_area_lock deadlock in v2:
https://lkml.org/lkml/2022/11/11/493

2. Provide static inline empty functions for kmem_valid_obj() and kmem_dump_obj()
when CONFIG_PRINTK=n.

v1 --> v2:
1. Remove condition "(unsigned long)rhp->func & 0x3", it have problems on x86.
2. Paul E. McKenney helped me update the commit message, thanks.


Zhen Lei (3):
mm: Remove kmem_valid_obj()
rcu: Dump memory object info if callback function is invalid
mm: Dump the memory of slab object in kmem_dump_obj()

include/linux/slab.h | 5 +--
kernel/rcu/rcu.h | 7 +++++
kernel/rcu/srcutiny.c | 1 +
kernel/rcu/srcutree.c | 1 +
kernel/rcu/tasks.h | 1 +
kernel/rcu/tiny.c | 1 +
kernel/rcu/tree.c | 1 +
mm/slab_common.c | 71 +++++++++++++++++++++++--------------------
mm/util.c | 4 +--
9 files changed, 54 insertions(+), 38 deletions(-)

--
2.34.1