From: Andrew Morton <akpm@linux-foundation.org>
To: Alexander Potapenko <glider@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
syzbot <syzbot+ece2915262061d6e0ac1@syzkaller.appspotmail.com>,
syzkaller-bugs@googlegroups.com,
Mel Gorman <mgorman@techsingularity.net>,
Vlastimil Babka <vbabka@suse.cz>,
Andrey Konovalov <andreyknvl@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Marco Elver <elver@google.com>,
kasan-dev <kasan-dev@googlegroups.com>,
linux-mm <linux-mm@kvack.org>
Subject: Re: [PATCH] kasan,kmsan: remove __GFP_KSWAPD_RECLAIM usage from kasan/kmsan
Date: Fri, 9 Jun 2023 15:31:24 -0700 [thread overview]
Message-ID: <20230609153124.11905393c03660369f4f5997@linux-foundation.org> (raw)
In-Reply-To: <CAG_fn=UTTbkGeOX0teGcNOeobtgV=mfGOefZpV-NTN4Ouus7xA@mail.gmail.com>
On Wed, 31 May 2023 15:31:53 +0200 Alexander Potapenko <glider@google.com> wrote:
> On Mon, May 29, 2023 at 3:08 AM Huang, Ying <ying.huang@intel.com> wrote:
> >
> > ? Handa <penguin-kernel@I-love.SAKURA.ne.jp> writes:
> >
> > > syzbot is reporting lockdep warning in __stack_depot_save(), for
> > > the caller of __stack_depot_save() (i.e. __kasan_record_aux_stack() in
> > > this report) is responsible for masking __GFP_KSWAPD_RECLAIM flag in
> > > order not to wake kswapd which in turn wakes kcompactd.
> > >
> > > Since kasan/kmsan functions might be called with arbitrary locks held,
> > > mask __GFP_KSWAPD_RECLAIM flag from all GFP_NOWAIT/GFP_ATOMIC allocations
> > > in kasan/kmsan.
> > >
> > > Note that kmsan_save_stack_with_flags() is changed to mask both
> > > __GFP_DIRECT_RECLAIM flag and __GFP_KSWAPD_RECLAIM flag, for
> > > wakeup_kswapd() from wake_all_kswapds() from __alloc_pages_slowpath()
> > > calls wakeup_kcompactd() if __GFP_KSWAPD_RECLAIM flag is set and
> > > __GFP_DIRECT_RECLAIM flag is not set.
> > >
> > > Reported-by: syzbot <syzbot+ece2915262061d6e0ac1@syzkaller.appspotmail.com>
> > > Closes: https://syzkaller.appspot.com/bug?extid=ece2915262061d6e0ac1
> > > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> >
> > This looks good to me. Thanks!
> >
> > Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
>
> Sorry for the late reply, but maybe it would be better to mask this
> flag in __stack_depot_save() (lib/stackdepot.c) instead?
> We are already masking out a number of flags there, and the problem
> seems quite generic.
Tetsuo?
next prev parent reply other threads:[~2023-06-09 22:31 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <000000000000cef3a005fc1bcc80@google.com>
2023-05-20 11:02 ` [syzbot] [kernel?] possible deadlock in scheduler_tick (2) Tetsuo Handa
2023-05-20 11:33 ` [PATCH] lib/stackdepot: stackdepot: don't use __GFP_KSWAPD_RECLAIM from __stack_depot_save() if atomic context Tetsuo Handa
2023-05-20 13:14 ` Tetsuo Handa
2023-05-20 22:44 ` Tetsuo Handa
2023-05-22 2:13 ` Huang, Ying
2023-05-22 2:47 ` Tetsuo Handa
2023-05-22 3:07 ` Huang, Ying
2023-05-22 11:33 ` Tetsuo Handa
2023-05-23 0:07 ` Huang, Ying
2023-05-23 0:45 ` Tetsuo Handa
2023-05-23 1:10 ` Huang, Ying
2023-05-24 12:09 ` Michal Hocko
2023-05-27 15:25 ` [PATCH] kasan,kmsan: remove __GFP_KSWAPD_RECLAIM usage from kasan/kmsan Tetsuo Handa
2023-05-29 1:07 ` Huang, Ying
2023-05-31 13:31 ` Alexander Potapenko
2023-06-09 22:31 ` Andrew Morton [this message]
[not found] ` <19d6c965-a9cf-16a5-6537-a02823d67c0a@I-love.SAKURA.ne.jp>
2023-06-12 1:30 ` [PATCH v3] lib/stackdepot: fix gfp flags manipulation in __stack_depot_save() Huang, Ying
2023-06-21 12:56 ` Alexander Potapenko
2023-06-21 14:07 ` Tetsuo Handa
2023-06-21 14:42 ` Alexander Potapenko
2023-06-21 14:54 ` Tetsuo Handa
2023-06-21 15:37 ` [PATCH] kasan,kmsan: remove __GFP_KSWAPD_RECLAIM usage from kasan/kmsan Alexander Potapenko
2023-05-27 21:01 ` [syzbot] [ntfs3?] possible deadlock in scheduler_tick (2) syzbot
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