Messages in this thread |  | | From | Dmitry Vyukov <> | Date | Wed, 16 Sep 2020 13:28:19 +0200 | Subject | Re: [PATCH v2] lockdep: Allow tuning tracing capacity constants. |
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On Fri, Sep 4, 2020 at 6:05 PM Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> wrote: > > 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.
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Peter, do you still have concerns with this?
Both MAX_LOCKDEP_ENTRIES and MAX_LOCKDEP_CHAINS still fire on syzbot a lot and harm ability to test whole kernel: https://syzkaller.appspot.com/bug?id=3d97ba93fb3566000c1c59691ea427370d33ea1b https://syzkaller.appspot.com/bug?id=63fc8d0501c39609dd2f268e4190ec9a72619563
I hate disabling lockdep entirely as it also finds lots of useful things.
> 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(-) > >
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