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Message-ID: <75ece297-e936-48f5-9daa-35a6bd740f76@paulmck-laptop>
Date: Fri, 11 Aug 2023 09:07:20 -0700
From: "Paul E. McKenney" <paulmck@...nel.org>
To: thunder.leizhen@...weicloud.com
Cc: Christoph Lameter <cl@...ux.com>,
Pekka Enberg <penberg@...nel.org>,
David Rientjes <rientjes@...gle.com>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
Andrew Morton <akpm@...ux-foundation.org>,
Vlastimil Babka <vbabka@...e.cz>,
Roman Gushchin <roman.gushchin@...ux.dev>,
Hyeonggon Yoo <42.hyeyoo@...il.com>, linux-mm@...ck.org,
Frederic Weisbecker <frederic@...nel.org>,
Neeraj Upadhyay <quic_neeraju@...cinc.com>,
Joel Fernandes <joel@...lfernandes.org>,
Josh Triplett <josh@...htriplett.org>,
Boqun Feng <boqun.feng@...il.com>,
Steven Rostedt <rostedt@...dmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Lai Jiangshan <jiangshanlai@...il.com>,
Zqiang <qiang.zhang1211@...il.com>, rcu@...r.kernel.org,
linux-kernel@...r.kernel.org, Zhen Lei <thunder.leizhen@...wei.com>
Subject: Re: [PATCH v7 0/2] rcu: Dump memory object info if callback function
is invalid
On Sat, Aug 05, 2023 at 11:17:24AM +0800, thunder.leizhen@...weicloud.com wrote:
> From: Zhen Lei <thunder.leizhen@...wei.com>
>
> v6 --> v7:
> To avoid snowballing, resend the two RCU-related patches that we've discussed
> OK. The remaining three patches themselves do not need to be gone into RCU tree,
> I'll send them separately for discussion.
>
> v5 --> v6:
> 1. Use print_hex_dump() to dump the memory of slab object.
> 2. Add a new dump prefix DUMP_PREFIX_ADDRESS_LOW16
> 3. Minimize the output width of the offset
>
> 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 (2):
> mm: Remove kmem_valid_obj()
> rcu: Dump memory object info if callback function is invalid
Queued both on -rcu, thank you all!
Thanx, Paul
> 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 | 41 +++++++++++------------------------------
> mm/util.c | 4 +---
> 9 files changed, 27 insertions(+), 35 deletions(-)
>
> --
> 2.34.1
>
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