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Tue, 07 Apr 2020 18:37:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:in-reply-to:message-id:subject :from:to; bh=iTgwp6BguOdJAZ/PeO1dtbonSopyEraPaAZfeMz81ms=; b=AJtLrHbe8dqsSTVD0fLCaj7G/Ulm7WpRh+9JVC4v4yeLEFHH2IBEEBtJLjs0dGDrbw tF12yPTPAJT2OlhOfrDXexa6+FdEf3RrM6n9O9xxD1nh7H75zsxaLHoSSmq33VJq18oT yLel4hJxsxIw0P7TZ+9AKnVUC6SSV0HdJw2bSRuBowf/2J+0AFm1W0Ei10cvMuFSMhcY rSJspSnuhiMaKAIknguz79a8MpH2PD7vvI2ITgIHfi8jfPnI5P6dLMzo+7nVxrcQqUaS AKXLsk25kqIsG1c/27dKpQbtDRZSdR8yXO2IBOZzA9JbcS8o14MoP+I+FTNGDm1kHfwL KbCQ== X-Gm-Message-State: AGi0PuYslOCauKQIRm1cIP82xxATdf29Z+xNSmnEYdfbWIyNwJoJ3GyG zkeUL0J+jResnhKWHJUeuPYPTf2crnVzzxPqQ7Jsbn41EZQ1 X-Google-Smtp-Source: APiQypJoZ+PLIMyU+FBlf/9o4hbRkZbgCiJpClZPLiVFx5BXXXgRP+Xs4zPCgzyN+hW9Ww8pJkEV2/pevvcAba6PfBQUlo7EPwTK MIME-Version: 1.0 X-Received: by 2002:a92:8659:: with SMTP id g86mr5656827ild.267.1586309835938; Tue, 07 Apr 2020 18:37:15 -0700 (PDT) Date: Tue, 07 Apr 2020 18:37:15 -0700 In-Reply-To: <00000000000005c65d05a2b90e70@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000046629905a2bd8acc@google.com> Subject: Re: WARNING: bad unlock balance in __get_user_pages_remote From: syzbot To: akpm@linux-foundation.org, bgeffon@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, peterx@redhat.com, syzkaller-bugs@googlegroups.com, torvalds@linux-foundation.org Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000020, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: syzbot has found a reproducer for the following crash on: HEAD commit: 763dede1 Merge tag 'for-linus-5.7-rc1' of git://git.kernel.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17731b0be00000 kernel config: https://syzkaller.appspot.com/x/.config?x=12205d036cec317f dashboard link: https://syzkaller.appspot.com/bug?extid=a8c70b7f3579fc0587dc compiler: gcc (GCC) 9.0.0 20181231 (experimental) userspace arch: i386 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=135855cde00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=149ea07de00000 The bug was bisected to: commit 71335f37c5e8ec9225285206f7f875057b9737ad Author: Peter Xu Date: Thu Apr 2 04:08:53 2020 +0000 mm/gup: allow to react to fatal signals bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17dba9b3e00000 final crash: https://syzkaller.appspot.com/x/report.txt?x=143ba9b3e00000 console output: https://syzkaller.appspot.com/x/log.txt?x=103ba9b3e00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+a8c70b7f3579fc0587dc@syzkaller.appspotmail.com Fixes: 71335f37c5e8 ("mm/gup: allow to react to fatal signals") ===================================== WARNING: bad unlock balance detected! 5.6.0-syzkaller #0 Not tainted ------------------------------------- syz-executor151/7052 is trying to release lock (&mm->mmap_sem) at: [] __get_user_pages_locked mm/gup.c:1366 [inline] [] __get_user_pages_remote mm/gup.c:1831 [inline] [] __get_user_pages_remote+0x540/0x740 mm/gup.c:1806 but there are no more locks to release! other info that might help us debug this: no locks held by syz-executor151/7052. stack backtrace: CPU: 0 PID: 7052 Comm: syz-executor151 Not tainted 5.6.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 __lock_release kernel/locking/lockdep.c:4633 [inline] lock_release+0x586/0x800 kernel/locking/lockdep.c:4941 up_read+0x79/0x750 kernel/locking/rwsem.c:1573 __get_user_pages_locked mm/gup.c:1366 [inline] __get_user_pages_remote mm/gup.c:1831 [inline] __get_user_pages_remote+0x540/0x740 mm/gup.c:1806 pin_user_pages_remote+0x67/0xa0 mm/gup.c:2897 process_vm_rw_single_vec mm/process_vm_access.c:108 [inline] process_vm_rw_core.isra.0+0x423/0x940 mm/process_vm_access.c:218 compat_process_vm_rw+0x21f/0x240 mm/process_vm_access.c:343 __do_compat_sys_process_vm_writev mm/process_vm_access.c:370 [inline] __se_compat_sys_process_vm_writev mm/process_vm_access.c:363 [inline] __ia32_compat_sys_process_vm_writev+0xdc/0x1b0 mm/process_vm_access.c:363 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline] do_fast_syscall_32+0x270/0xe90 arch/x86/entry/common.c:396 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 ------------[ cut here ]------------ DEBUG_RWSEMS_WARN_ON(tmp < 0): count = 0xffffffffffffff00, magic = 0xffff88809e2392f8, owner = 0x3, curr 0xffff88809a6c6240, list empty WARNING: CPU: 1 PID: 7052 at kernel/locking/rwsem.c:1435 __up_read kernel/locking/rwsem.c:1435 [inline] WARNING: CPU: 1 PID: 7052 at kernel/locking/rwsem.c:1435 up_read+0x5f9/0x750 kernel/locking/rwsem.c:1574