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bh=EEdLkvABck34PZtvq+YRRZg0qzNnBgP0txfTuuVN9bQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=VF3DiryExmLLgZHG7ulVbdlMeQWbx9mA0ybAvx1bJa791vJOK/Z+s8XyfqhA88AOW LSFDnGW4urOqUyEDhc0i2R5GZZ+35lv0ilbLs/BENeRRfElUkzUCvvwCuD8VwZdfS1 YVNttVEHCeswtOIzPS0ZLcbkdiEszl3okzdxkSMA= Date: Fri, 9 Jun 2023 15:31:24 -0700 From: Andrew Morton To: Alexander Potapenko Cc: "Huang, Ying" , Tetsuo Handa , syzbot , syzkaller-bugs@googlegroups.com, Mel Gorman , Vlastimil Babka , Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , Vincenzo Frascino , Marco Elver , kasan-dev , linux-mm Subject: Re: [PATCH] kasan,kmsan: remove __GFP_KSWAPD_RECLAIM usage from kasan/kmsan Message-Id: <20230609153124.11905393c03660369f4f5997@linux-foundation.org> In-Reply-To: References: <000000000000cef3a005fc1bcc80@google.com> <656cb4f5-998b-c8d7-3c61-c2d37aa90f9a@I-love.SAKURA.ne.jp> <87353gx7wd.fsf@yhuang6-desk2.ccr.corp.intel.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: EB9941C0019 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: 3gjrm5rsfssi15xrgr4qqrrpth86441n X-HE-Tag: 1686349886-370392 X-HE-Meta: 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 J8Kb3NO6 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 31 May 2023 15:31:53 +0200 Alexander Potapenko wrote: > On Mon, May 29, 2023 at 3:08 AM Huang, Ying wrote: > > > > ? Handa 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 > > > Closes: https://syzkaller.appspot.com/bug?extid=ece2915262061d6e0ac1 > > > Signed-off-by: Tetsuo Handa > > > > This looks good to me. Thanks! > > > > Reviewed-by: "Huang, Ying" > > 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?