Re: [PATCH v2] lockdep: Allow tuning tracing capacity constants.

From: Tetsuo Handa
Date: Fri Sep 04 2020 - 12:06:17 EST


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@xxxxxxxxxxxxxxxxxxxxxxxxx>
> Reported-by: syzbot <syzbot+91fd909b6e62ebe06131@xxxxxxxxxxxxxxxxxxxxxxxxx>
> Reported-by: syzbot <syzbot+62ebe501c1ce9a91f68c@xxxxxxxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> ---
> kernel/locking/lockdep.c | 2 +-
> kernel/locking/lockdep_internals.h | 8 +++---
> lib/Kconfig.debug | 40 ++++++++++++++++++++++++++++++
> 3 files changed, 45 insertions(+), 5 deletions(-)
>