From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.7 required=3.0 tests=BAYES_00,FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7EDC0C07E9D for ; Sun, 4 Jul 2021 11:51:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 731AA6135B for ; Sun, 4 Jul 2021 11:51:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229811AbhGDLyB (ORCPT ); Sun, 4 Jul 2021 07:54:01 -0400 Received: from mail-io1-f71.google.com ([209.85.166.71]:38517 "EHLO mail-io1-f71.google.com" rhost-flags-OK-OK-OK-OK) by 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ABdhPJxgG1Zmk2Hb/OM312E6Ut3E+4dfoWWP62/Aybr62+dtODt08SDlleLZkyvhD/yxvFVOjL3ZZp2WzC/nj01fgCYqiwT7Ej7+ MIME-Version: 1.0 X-Received: by 2002:a05:6602:19:: with SMTP id b25mr7536575ioa.93.1625399480372; Sun, 04 Jul 2021 04:51:20 -0700 (PDT) Date: Sun, 04 Jul 2021 04:51:20 -0700 In-Reply-To: <0000000000002054ab05c6486083@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000a5532d05c64ace69@google.com> Subject: Re: [syzbot] possible deadlock in __fs_reclaim_acquire From: syzbot To: akpm@linux-foundation.org, andrii@kernel.org, ast@kernel.org, axboe@kernel.dk, bpf@vger.kernel.org, christian@brauner.io, daniel@iogearbox.net, ebiederm@xmission.com, john.fastabend@gmail.com, kafai@fb.com, kpsingh@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, peterz@infradead.org, shakeelb@google.com, songliubraving@fb.com, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk, yhs@fb.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot has found a reproducer for the following issue on: HEAD commit: 3dbdb38e Merge branch 'for-5.14' of git://git.kernel.org/p.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17e0b9d8300000 kernel config: https://syzkaller.appspot.com/x/.config?x=1700b0b2b41cd52c dashboard link: https://syzkaller.appspot.com/bug?extid=127fd7828d6eeb611703 compiler: Debian clang version 11.0.1-2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10542f52300000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+127fd7828d6eeb611703@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected 5.13.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-execprog/8416 is trying to acquire lock: ffffffff8cfd6720 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x0/0x30 mm/page_alloc.c:4222 but task is already holding lock: ffff8880b9b31088 (lock#2){-.-.}-{2:2}, at: local_lock_acquire+0x7/0x130 include/linux/local_lock_internal.h:41 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (lock#2){-.-.}-{2:2}: lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625 local_lock_acquire+0x23/0x130 include/linux/local_lock_internal.h:42 free_unref_page+0x242/0x550 mm/page_alloc.c:3439 mm_free_pgd kernel/fork.c:636 [inline] __mmdrop+0xae/0x3f0 kernel/fork.c:687 mmdrop include/linux/sched/mm.h:49 [inline] finish_task_switch+0x221/0x630 kernel/sched/core.c:4582 context_switch kernel/sched/core.c:4686 [inline] __schedule+0xc0f/0x11f0 kernel/sched/core.c:5940 preempt_schedule_notrace+0x12c/0x170 kernel/sched/core.c:6179 preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:36 rcu_read_unlock_sched_notrace include/linux/rcupdate.h:809 [inline] trace_lock_release+0x9f/0x140 include/trace/events/lock.h:58 lock_release+0x81/0x7b0 kernel/locking/lockdep.c:5636 might_alloc include/linux/sched/mm.h:199 [inline] slab_pre_alloc_hook mm/slab.h:485 [inline] slab_alloc_node mm/slub.c:2891 [inline] slab_alloc mm/slub.c:2978 [inline] kmem_cache_alloc+0x41/0x340 mm/slub.c:2983 kmem_cache_zalloc include/linux/slab.h:711 [inline] attach_epitem fs/eventpoll.c:1414 [inline] ep_insert fs/eventpoll.c:1468 [inline] do_epoll_ctl+0x13a7/0x2f70 fs/eventpoll.c:2133 __do_sys_epoll_ctl fs/eventpoll.c:2184 [inline] __se_sys_epoll_ctl fs/eventpoll.c:2175 [inline] __x64_sys_epoll_ctl+0x14e/0x190 fs/eventpoll.c:2175 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (fs_reclaim){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add+0x4f9/0x5b30 kernel/locking/lockdep.c:3174 validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x4476/0x6100 kernel/locking/lockdep.c:5015 lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625 __fs_reclaim_acquire+0x20/0x30 mm/page_alloc.c:4564 fs_reclaim_acquire+0x59/0xf0 mm/page_alloc.c:4578 prepare_alloc_pages+0x151/0x5a0 mm/page_alloc.c:5176 __alloc_pages+0x14d/0x5f0 mm/page_alloc.c:5375 stack_depot_save+0x361/0x490 lib/stackdepot.c:303 save_stack+0xf9/0x1f0 mm/page_owner.c:120 __set_page_owner+0x42/0x2f0 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2445 [inline] __alloc_pages_bulk+0x9f2/0x1090 mm/page_alloc.c:5313 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline] vm_area_alloc_pages mm/vmalloc.c:2775 [inline] __vmalloc_area_node mm/vmalloc.c:2845 [inline] __vmalloc_node_range+0x3ad/0x7f0 mm/vmalloc.c:2947 vmalloc_user+0x70/0x80 mm/vmalloc.c:3082 kcov_mmap+0x28/0x130 kernel/kcov.c:465 call_mmap include/linux/fs.h:2119 [inline] mmap_region+0x1410/0x1df0 mm/mmap.c:1809 do_mmap+0x930/0x11a0 mm/mmap.c:1585 vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:519 ksys_mmap_pgoff+0x504/0x7b0 mm/mmap.c:1636 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(lock#2); lock(fs_reclaim); lock(lock#2); lock(fs_reclaim); *** DEADLOCK *** 2 locks held by syz-execprog/8416: #0: ffff8880161e0128 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline] #0: ffff8880161e0128 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x14d/0x2b0 mm/util.c:517 #1: ffff8880b9b31088 (lock#2){-.-.}-{2:2}, at: local_lock_acquire+0x7/0x130 include/linux/local_lock_internal.h:41 stack backtrace: CPU: 1 PID: 8416 Comm: syz-execprog Not tainted 5.13.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack_lvl+0x1ae/0x29f lib/dump_stack.c:96 print_circular_bug+0xb17/0xdc0 kernel/locking/lockdep.c:2009 check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2131 check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add+0x4f9/0x5b30 kernel/locking/lockdep.c:3174 validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x4476/0x6100 kernel/locking/lockdep.c:5015 lock_acquire+0x182/0x4a0 kernel/locking/lockdep.c:5625 __fs_reclaim_acquire+0x20/0x30 mm/page_alloc.c:4564 fs_reclaim_acquire+0x59/0xf0 mm/page_alloc.c:4578 prepare_alloc_pages+0x151/0x5a0 mm/page_alloc.c:5176 __alloc_pages+0x14d/0x5f0 mm/page_alloc.c:5375 stack_depot_save+0x361/0x490 lib/stackdepot.c:303 save_stack+0xf9/0x1f0 mm/page_owner.c:120 __set_page_owner+0x42/0x2f0 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2445 [inline] __alloc_pages_bulk+0x9f2/0x1090 mm/page_alloc.c:5313 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline] vm_area_alloc_pages mm/vmalloc.c:2775 [inline] __vmalloc_area_node mm/vmalloc.c:2845 [inline] __vmalloc_node_range+0x3ad/0x7f0 mm/vmalloc.c:2947 vmalloc_user+0x70/0x80 mm/vmalloc.c:3082 kcov_mmap+0x28/0x130 kernel/kcov.c:465 call_mmap include/linux/fs.h:2119 [inline] mmap_region+0x1410/0x1df0 mm/mmap.c:1809 do_mmap+0x930/0x11a0 mm/mmap.c:1585 vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:519 ksys_mmap_pgoff+0x504/0x7b0 mm/mmap.c:1636 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4b132a Code: e8 db 57 fb ff 48 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 4c 8b 54 24 28 4c 8b 44 24 30 4c 8b 4c 24 38 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 40 ff ff ff ff 48 c7 44 24 48 RSP: 002b:000000c000173a10 EFLAGS: 00000202 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 000000c000020800 RCX: 00000000004b132a RDX: 0000000000000003 RSI: 0000000000080000 RDI: 0000000000000000 RBP: 000000c000173a70 R08: 0000000000000006 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000202 R12: 0000000000727f1a R13: 00000000000001f6 R14: 0000000000000200 R15: 0000000000000100 BUG: sleeping function called from invalid context at mm/page_alloc.c:5179 in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 8416, name: syz-execprog INFO: lockdep is turned off. irq event stamp: 70646 hardirqs last enabled at (70645): [] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] hardirqs last enabled at (70645): [] _raw_spin_unlock_irqrestore+0x8b/0x120 kernel/locking/spinlock.c:191 hardirqs last disabled at (70646): [] __alloc_pages_bulk+0x801/0x1090 mm/page_alloc.c:5291 softirqs last enabled at (69738): [] invoke_softirq kernel/softirq.c:432 [inline] softirqs last enabled at (69738): [] __irq_exit_rcu+0x21b/0x260 kernel/softirq.c:636 softirqs last disabled at (69687): [] invoke_softirq kernel/softirq.c:432 [inline] softirqs last disabled at (69687): [] __irq_exit_rcu+0x21b/0x260 kernel/softirq.c:636 CPU: 1 PID: 8416 Comm: syz-execprog Not tainted 5.13.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack_lvl+0x1ae/0x29f lib/dump_stack.c:96 ___might_sleep+0x4e5/0x6b0 kernel/sched/core.c:9153 prepare_alloc_pages+0x1c0/0x5a0 mm/page_alloc.c:5179 __alloc_pages+0x14d/0x5f0 mm/page_alloc.c:5375 stack_depot_save+0x361/0x490 lib/stackdepot.c:303 save_stack+0xf9/0x1f0 mm/page_owner.c:120 __set_page_owner+0x42/0x2f0 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2445 [inline] __alloc_pages_bulk+0x9f2/0x1090 mm/page_alloc.c:5313 alloc_pages_bulk_array_node include/linux/gfp.h:557 [inline] vm_area_alloc_pages mm/vmalloc.c:2775 [inline] __vmalloc_area_node mm/vmalloc.c:2845 [inline] __vmalloc_node_range+0x3ad/0x7f0 mm/vmalloc.c:2947 vmalloc_user+0x70/0x80 mm/vmalloc.c:3082 kcov_mmap+0x28/0x130 kernel/kcov.c:465 call_mmap include/linux/fs.h:2119 [inline] mmap_region+0x1410/0x1df0 mm/mmap.c:1809 do_mmap+0x930/0x11a0 mm/mmap.c:1585 vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:519 ksys_mmap_pgoff+0x504/0x7b0 mm/mmap.c:1636 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4b132a Code: e8 db 57 fb ff 48 8b 7c 24 10 48 8b 74 24 18 48 8b 54 24 20 4c 8b 54 24 28 4c 8b 44 24 30 4c 8b 4c 24 38 48 8b 44 24 08 0f 05 <48> 3d 01 f0 ff ff 76 20 48 c7 44 24 40 ff ff ff ff 48 c7 44 24 48 RSP: 002b:000000c000173a10 EFLAGS: 00000202 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 000000c000020800 RCX: 00000000004b132a RDX: 0000000000000003 RSI: 0000000000080000 RDI: 0000000000000000 RBP: 000000c000173a70 R08: 0000000000000006 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000202 R12: 0000000000727f1a R13: 00000000000001f6 R14: 0000000000000200 R15: 0000000000000100