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Subject: Re: [PATCH v2] lockdep: Allow tuning tracing capacity constants.
From:   Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     linux-kernel@vger.kernel.org, Dmitry Vyukov <dvyukov@google.com>
References: <1595640639-9310-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp>
 <384ce711-25c5-553b-8d22-965847132fbd@i-love.sakura.ne.jp>
Message-ID: <0f7233f7-a04a-e9c9-7920-3a170cc97e4b@i-love.sakura.ne.jp>
Date:   Sat, 5 Sep 2020 01:05:30 +0900
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Hello. Can we apply this patch?

This patch addresses top crashers for syzbot, and applying this patch
will help utilizing syzbot's resource for finding other bugs.

On 2020/08/28 0:20, Tetsuo Handa wrote:
> Since syzkaller continues various test cases until the kernel crashes,
> syzkaller tends to examine more locking dependencies than normal systems.
> As a result, syzbot is reporting that the fuzz testing was terminated
> due to hitting upper limits lockdep can track [1] [2] [3].
> 
> Let's allow individually tuning upper limits via kernel config options
> (based on an assumption that there is no inter-dependency among these
> constants).
> 
> [1] https://syzkaller.appspot.com/bug?id=3d97ba93fb3566000c1c59691ea427370d33ea1b
> [2] https://syzkaller.appspot.com/bug?id=381cb436fe60dc03d7fd2a092b46d7f09542a72a
> [3] https://syzkaller.appspot.com/bug?id=a588183ac34c1437fc0785e8f220e88282e5a29f
> 
> Reported-by: syzbot <syzbot+cd0ec5211ac07c18c049@syzkaller.appspotmail.com>
> Reported-by: syzbot <syzbot+91fd909b6e62ebe06131@syzkaller.appspotmail.com>
> Reported-by: syzbot <syzbot+62ebe501c1ce9a91f68c@syzkaller.appspotmail.com>
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> ---
>  kernel/locking/lockdep.c           |  2 +-
>  kernel/locking/lockdep_internals.h |  8 +++---
>  lib/Kconfig.debug                  | 40 ++++++++++++++++++++++++++++++
>  3 files changed, 45 insertions(+), 5 deletions(-)
>