From: Jason Gunthorpe <jgg@ziepe.ca>
To: Bob Pearson <rpearsonhpe@gmail.com>
Cc: Yanjun Zhu <yanjun.zhu@linux.dev>,
leon@kernel.org, linux-rdma@vger.kernel.org
Subject: Re: [PATCHv4 1/2] RDMA/rxe: Fix a dead lock problem
Date: Wed, 20 Apr 2022 13:41:22 -0300 [thread overview]
Message-ID: <20220420164122.GS64706@ziepe.ca> (raw)
In-Reply-To: <726e75b0-c165-92f8-c367-1a5a777bc8b1@gmail.com>
On Fri, Apr 15, 2022 at 01:35:58AM -0500, Bob Pearson wrote:
> I mean the trace you show here shows an instance of xa_lock being
> acquired from the pd pool followed by an instance of xa_lock being
> acquired from rxe_pool_get_index from the ah pool. They are different
> locks. They can't deadlock against each other. So there must be
> some other trace (not shown) that also gets xa_lock from the ah pool.
This is because lockdep groups locks by allocation point into the same
'lock class' so as far as lockdep is concerned the AH and PD's are all
the same lock and you'll get reports like the above.
The same issue will show up with AH only, you just need to hit a path
that allocates an AH from a process context, like uverbs.
Jason
next prev parent reply other threads:[~2022-04-20 16:41 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-15 19:56 [PATCHv4 1/2] RDMA/rxe: Fix a dead lock problem yanjun.zhu
2022-04-15 5:37 ` Bob Pearson
2022-04-15 5:54 ` Yanjun Zhu
2022-04-15 6:35 ` Bob Pearson
2022-04-15 6:49 ` Yanjun Zhu
2022-04-15 7:22 ` Bob Pearson
2022-04-15 7:32 ` Yanjun Zhu
2022-04-15 7:35 ` Bob Pearson
2022-04-15 7:42 ` Yanjun Zhu
2022-04-15 7:49 ` Bob Pearson
2022-04-15 7:52 ` Yanjun Zhu
2022-04-15 7:44 ` Bob Pearson
2022-04-15 8:50 ` Yanjun Zhu
2022-04-20 16:41 ` Jason Gunthorpe [this message]
2022-04-15 10:25 ` Yanjun Zhu
2022-04-15 15:19 ` Yanjun Zhu
2022-04-15 19:56 ` [PATCH 2/2] RDMA/rxe: Use different xa locks on different path yanjun.zhu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220420164122.GS64706@ziepe.ca \
--to=jgg@ziepe.ca \
--cc=leon@kernel.org \
--cc=linux-rdma@vger.kernel.org \
--cc=rpearsonhpe@gmail.com \
--cc=yanjun.zhu@linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.