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AJvYcCWHiaEpqJW39hWHn83woRSdbOrvsz7u1BhgF8II7/9h8F+WF+r13UYijOA6DCuq27/qj4Ym75hlSq8=@vger.kernel.org X-Gm-Message-State: AOJu0YzBE4hSndEwHUeBpaMhLW9klsQGTaf0onG27r8qmJNxtuKuukES 68x2Zscwe5NQvceC4iFeV5i6+26sSniCBsgEfiv+rKPKczEcR2O5zzdyRNg9UC9tOTyFHUxhLM+ e3Xl5hwFUuEDbTzGgkf7GyRAe89qD+RJOx9mhRgKDlYAHe/zWYk0+LbcYzzA= X-Google-Smtp-Source: AGHT+IGhlk8rLUpX7k25k9Lw7ZjJQC4w6OTHgju8dQxy1Auh1CRCgV36cDXsYKtm7EV8RHncKwcHfTJ3Bv6TqTOTl56Q3eJdElb0 Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:3094:b0:44d:ae36:dd86 with SMTP id 5614622812f47-45115b3cb56mr16027752b6e.59.1764646529024; Mon, 01 Dec 2025 19:35:29 -0800 (PST) Date: Mon, 01 Dec 2025 19:35:29 -0800 In-Reply-To: <689a0c9f.050a0220.51d73.009e.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <692e5e81.a70a0220.2ea503.00bf.GAE@google.com> Subject: Re: [syzbot] [xfs?] possible deadlock in xfs_icwalk_ag (3) From: syzbot To: cem@kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, mmpgouride@gmail.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 1d18101a644e Merge tag 'kernel-6.19-rc1.cred' of git://git.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=13d1a192580000 kernel config: https://syzkaller.appspot.com/x/.config?x=a1db0fea040c2a9f dashboard link: https://syzkaller.appspot.com/bug?extid=789028412a4af61a2b61 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10ae38c2580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17606512580000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-1d18101a.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/98f78b52cccd/vmlinux-1d18101a.xz kernel image: https://storage.googleapis.com/syzbot-assets/7a8898061bfb/bzImage-1d18101a.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/28373feef258/mount_0.gz fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=172e38c2580000) IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+789028412a4af61a2b61@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kswapd0/79 is trying to acquire lock: ffff888041afd798 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_reclaim_inode fs/xfs/xfs_icache.c:1040 [inline] ffff888041afd798 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1732 [inline] ffff888041afd798 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_icwalk_ag+0x12c5/0x1ab0 fs/xfs/xfs_icache.c:1814 but task is already holding lock: ffffffff8e047ae0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:7015 [inline] ffffffff8e047ae0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x951/0x2800 mm/vmscan.c:7389 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __fs_reclaim_acquire mm/page_alloc.c:4264 [inline] fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4278 might_alloc include/linux/sched/mm.h:318 [inline] slab_pre_alloc_hook mm/slub.c:4929 [inline] slab_alloc_node mm/slub.c:5264 [inline] __kmalloc_cache_noprof+0x40/0x6f0 mm/slub.c:5766 kmalloc_noprof include/linux/slab.h:957 [inline] iomap_fill_dirty_folios+0xf4/0x260 fs/iomap/buffered-io.c:1557 xfs_buffered_write_iomap_begin+0xa23/0x1a70 fs/xfs/xfs_iomap.c:1857 iomap_iter+0x5f2/0xf10 fs/iomap/iter.c:110 iomap_zero_range+0x1cc/0xa50 fs/iomap/buffered-io.c:1590 iomap_truncate_page+0xb1/0x110 fs/iomap/buffered-io.c:1629 xfs_setattr_size+0x452/0xee0 fs/xfs/xfs_iops.c:996 __xfs_file_fallocate+0x10e1/0x1610 include/linux/fs.h:-1 xfs_file_fallocate+0x27b/0x340 fs/xfs/xfs_file.c:1462 vfs_fallocate+0x669/0x7e0 fs/open.c:342 ksys_fallocate fs/open.c:366 [inline] __do_sys_fallocate fs/open.c:371 [inline] __se_sys_fallocate fs/open.c:369 [inline] __x64_sys_fallocate+0xc0/0x110 fs/open.c:369 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&xfs_nondir_ilock_class){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write_nested+0x9d/0x200 kernel/locking/rwsem.c:1706 xfs_reclaim_inode fs/xfs/xfs_icache.c:1040 [inline] xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1732 [inline] xfs_icwalk_ag+0x12c5/0x1ab0 fs/xfs/xfs_icache.c:1814 xfs_icwalk fs/xfs/xfs_icache.c:1862 [inline] xfs_reclaim_inodes_nr+0x1e3/0x260 fs/xfs/xfs_icache.c:1106 super_cache_scan+0x41b/0x4b0 fs/super.c:228 do_shrink_slab+0x6ef/0x1110 mm/shrinker.c:437 shrink_slab_memcg mm/shrinker.c:550 [inline] shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628 shrink_one+0x28a/0x7c0 mm/vmscan.c:4955 shrink_many mm/vmscan.c:5016 [inline] lru_gen_shrink_node mm/vmscan.c:5094 [inline] shrink_node+0x315d/0x3780 mm/vmscan.c:6081 kswapd_shrink_node mm/vmscan.c:6941 [inline] balance_pgdat mm/vmscan.c:7124 [inline] kswapd+0x147c/0x2800 mm/vmscan.c:7389 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&xfs_nondir_ilock_class); lock(fs_reclaim); lock(&xfs_nondir_ilock_class); *** DEADLOCK *** 2 locks held by kswapd0/79: #0: ffffffff8e047ae0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:7015 [inline] #0: ffffffff8e047ae0 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x951/0x2800 mm/vmscan.c:7389 #1: ffff8880113de0e0 (&type->s_umount_key#55){++++}-{4:4}, at: super_trylock_shared fs/super.c:563 [inline] #1: ffff8880113de0e0 (&type->s_umount_key#55){++++}-{4:4}, at: super_cache_scan+0x91/0x4b0 fs/super.c:197 stack backtrace: CPU: 0 UID: 0 PID: 79 Comm: kswapd0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write_nested+0x9d/0x200 kernel/locking/rwsem.c:1706 xfs_reclaim_inode fs/xfs/xfs_icache.c:1040 [inline] xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1732 [inline] xfs_icwalk_ag+0x12c5/0x1ab0 fs/xfs/xfs_icache.c:1814 xfs_icwalk fs/xfs/xfs_icache.c:1862 [inline] xfs_reclaim_inodes_nr+0x1e3/0x260 fs/xfs/xfs_icache.c:1106 super_cache_scan+0x41b/0x4b0 fs/super.c:228 do_shrink_slab+0x6ef/0x1110 mm/shrinker.c:437 shrink_slab_memcg mm/shrinker.c:550 [inline] shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628 shrink_one+0x28a/0x7c0 mm/vmscan.c:4955 shrink_many mm/vmscan.c:5016 [inline] lru_gen_shrink_node mm/vmscan.c:5094 [inline] shrink_node+0x315d/0x3780 mm/vmscan.c:6081 kswapd_shrink_node mm/vmscan.c:6941 [inline] balance_pgdat mm/vmscan.c:7124 [inline] kswapd+0x147c/0x2800 mm/vmscan.c:7389 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.