On Thu, Apr 25, 2024 at 10:15:29PM -0700, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 3b68086599f8 Merge tag 'sched_urgent_for_v6.9_rc5' of git:.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=158206bb180000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f47e5e015c177e57 > dashboard link: https://syzkaller.appspot.com/bug?extid=1619d847a7b9ba3a9137 > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/caa90b55d476/disk-3b680865.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/17940f1c5e8f/vmlinux-3b680865.xz > kernel image: https://storage.googleapis.com/syzbot-assets/b03bd6929a1c/bzImage-3b680865.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+1619d847a7b9ba3a9137@xxxxxxxxxxxxxxxxxxxxxxxxx > > ====================================================== > WARNING: possible circular locking dependency detected > 6.9.0-rc4-syzkaller-00274-g3b68086599f8 #0 Not tainted > ------------------------------------------------------ > kswapd0/81 is trying to acquire lock: > ffff8881a895a610 (sb_internal#3){.+.+}-{0:0}, at: xfs_fs_dirty_inode+0x158/0x250 fs/xfs/xfs_super.c:689 > > but task is already holding lock: > ffffffff8e428e80 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6782 [inline] > ffffffff8e428e80 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb20/0x30c0 mm/vmscan.c:7164 > > which lock already depends on the new lock. > > > the existing dependency chain (in reverse order) is: > > -> #2 (fs_reclaim){+.+.}-{0:0}: > lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 > __fs_reclaim_acquire mm/page_alloc.c:3698 [inline] > fs_reclaim_acquire+0x88/0x140 mm/page_alloc.c:3712 > might_alloc include/linux/sched/mm.h:312 [inline] > slab_pre_alloc_hook mm/slub.c:3746 [inline] > slab_alloc_node mm/slub.c:3827 [inline] > kmalloc_trace+0x47/0x360 mm/slub.c:3992 > kmalloc include/linux/slab.h:628 [inline] > add_stack_record_to_list mm/page_owner.c:177 [inline] > inc_stack_record_count mm/page_owner.c:219 [inline] > __set_page_owner+0x561/0x810 mm/page_owner.c:334 > set_page_owner include/linux/page_owner.h:32 [inline] > post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534 > prep_new_page mm/page_alloc.c:1541 [inline] > get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317 > __alloc_pages+0x256/0x6c0 mm/page_alloc.c:4575 > __alloc_pages_node include/linux/gfp.h:238 [inline] > alloc_pages_node include/linux/gfp.h:261 [inline] > alloc_slab_page+0x5f/0x160 mm/slub.c:2175 > allocate_slab mm/slub.c:2338 [inline] > new_slab+0x84/0x2f0 mm/slub.c:2391 > ___slab_alloc+0xc73/0x1260 mm/slub.c:3525 > __slab_alloc mm/slub.c:3610 [inline] > __slab_alloc_node mm/slub.c:3663 [inline] > slab_alloc_node mm/slub.c:3835 [inline] > kmem_cache_alloc+0x252/0x340 mm/slub.c:3852 > kmem_cache_zalloc include/linux/slab.h:739 [inline] > xfs_btree_alloc_cursor fs/xfs/libxfs/xfs_btree.h:679 [inline] > xfs_refcountbt_init_cursor+0x65/0x2a0 fs/xfs/libxfs/xfs_refcount_btree.c:367 > xfs_reflink_find_shared fs/xfs/xfs_reflink.c:147 [inline] > xfs_reflink_trim_around_shared+0x53a/0x9d0 fs/xfs/xfs_reflink.c:194 > xfs_buffered_write_iomap_begin+0xebf/0x1b40 fs/xfs/xfs_iomap.c:1062 Hm. We've taken an ILOCK in xfs_buffered_write_iomap_begin, and now we're allocating a btree cursor but we don't have PF_MEMALLOC_NOFS set, nor do we pass GFP_NOFS. Ah, because nothing in this code path sets PF_MEMALLOC_NOFS explicitly, nor does it create a xfs_trans_alloc_empty, which would set that. Prior to the removal of kmem_alloc, I think we were much more aggressive about GFP_NOFS usage. Seeing as we're about to walk a btree, we probably want the empty transaction to guard against btree cycle livelocks. --D > iomap_iter+0x691/0xf60 fs/iomap/iter.c:91 > iomap_file_unshare+0x17a/0x710 fs/iomap/buffered-io.c:1364 > xfs_reflink_unshare+0x173/0x5f0 fs/xfs/xfs_reflink.c:1710 > xfs_file_fallocate+0x87c/0xd00 fs/xfs/xfs_file.c:1082 > vfs_fallocate+0x564/0x6c0 fs/open.c:330 > ksys_fallocate fs/open.c:353 [inline] > __do_sys_fallocate fs/open.c:361 [inline] > __se_sys_fallocate fs/open.c:359 [inline] > __x64_sys_fallocate+0xbd/0x110 fs/open.c:359 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > -> #1 (&xfs_nondir_ilock_class#3){++++}-{3:3}: > lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 > down_write_nested+0x3d/0x50 kernel/locking/rwsem.c:1695 > xfs_dquot_disk_alloc+0x399/0xe50 fs/xfs/xfs_dquot.c:332 > xfs_qm_dqread+0x1a3/0x650 fs/xfs/xfs_dquot.c:693 > xfs_qm_dqget+0x2bb/0x6f0 fs/xfs/xfs_dquot.c:905 > xfs_qm_quotacheck_dqadjust+0xea/0x5a0 fs/xfs/xfs_qm.c:1096 > xfs_qm_dqusage_adjust+0x4db/0x6f0 fs/xfs/xfs_qm.c:1215 > xfs_iwalk_ag_recs+0x4e0/0x860 fs/xfs/xfs_iwalk.c:213 > xfs_iwalk_run_callbacks+0x218/0x470 fs/xfs/xfs_iwalk.c:372 > xfs_iwalk_ag+0xa39/0xb50 fs/xfs/xfs_iwalk.c:478 > xfs_iwalk_ag_work+0xfb/0x1b0 fs/xfs/xfs_iwalk.c:620 > xfs_pwork_work+0x7f/0x190 fs/xfs/xfs_pwork.c:47 > process_one_work kernel/workqueue.c:3254 [inline] > process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3335 > worker_thread+0x86d/0xd70 kernel/workqueue.c:3416 > kthread+0x2f0/0x390 kernel/kthread.c:388 > ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > -> #0 (sb_internal#3){.+.+}-{0:0}: > check_prev_add kernel/locking/lockdep.c:3134 [inline] > check_prevs_add kernel/locking/lockdep.c:3253 [inline] > validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 > __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 > lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 > percpu_down_read include/linux/percpu-rwsem.h:51 [inline] > __sb_start_write include/linux/fs.h:1664 [inline] > sb_start_intwrite include/linux/fs.h:1847 [inline] > xfs_trans_alloc+0xe5/0x830 fs/xfs/xfs_trans.c:264 > xfs_fs_dirty_inode+0x158/0x250 fs/xfs/xfs_super.c:689 > __mark_inode_dirty+0x325/0xe20 fs/fs-writeback.c:2477 > mark_inode_dirty_sync include/linux/fs.h:2410 [inline] > iput+0x1fe/0x930 fs/inode.c:1764 > __dentry_kill+0x20d/0x630 fs/dcache.c:603 > shrink_kill+0xa9/0x2c0 fs/dcache.c:1048 > shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1075 > prune_dcache_sb+0x10f/0x180 fs/dcache.c:1156 > super_cache_scan+0x34f/0x4b0 fs/super.c:221 > do_shrink_slab+0x705/0x1160 mm/shrinker.c:435 > shrink_slab_memcg mm/shrinker.c:548 [inline] > shrink_slab+0x883/0x14d0 mm/shrinker.c:626 > shrink_node_memcgs mm/vmscan.c:5875 [inline] > shrink_node+0x11f5/0x2d60 mm/vmscan.c:5908 > kswapd_shrink_node mm/vmscan.c:6704 [inline] > balance_pgdat mm/vmscan.c:6895 [inline] > kswapd+0x1a25/0x30c0 mm/vmscan.c:7164 > kthread+0x2f0/0x390 kernel/kthread.c:388 > ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > other info that might help us debug this: > > Chain exists of: > sb_internal#3 --> &xfs_nondir_ilock_class#3 --> fs_reclaim > > Possible unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > lock(fs_reclaim); > lock(&xfs_nondir_ilock_class#3); > lock(fs_reclaim); > rlock(sb_internal#3); > > *** DEADLOCK *** > > 2 locks held by kswapd0/81: > #0: ffffffff8e428e80 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6782 [inline] > #0: ffffffff8e428e80 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb20/0x30c0 mm/vmscan.c:7164 > #1: ffff8881a895a0e0 (&type->s_umount_key#65){++++}-{3:3}, at: super_trylock_shared fs/super.c:561 [inline] > #1: ffff8881a895a0e0 (&type->s_umount_key#65){++++}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196 > > stack backtrace: > CPU: 1 PID: 81 Comm: kswapd0 Not tainted 6.9.0-rc4-syzkaller-00274-g3b68086599f8 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 > Call Trace: > <TASK> > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 > check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187 > check_prev_add kernel/locking/lockdep.c:3134 [inline] > check_prevs_add kernel/locking/lockdep.c:3253 [inline] > validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 > __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 > lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 > percpu_down_read include/linux/percpu-rwsem.h:51 [inline] > __sb_start_write include/linux/fs.h:1664 [inline] > sb_start_intwrite include/linux/fs.h:1847 [inline] > xfs_trans_alloc+0xe5/0x830 fs/xfs/xfs_trans.c:264 > xfs_fs_dirty_inode+0x158/0x250 fs/xfs/xfs_super.c:689 > __mark_inode_dirty+0x325/0xe20 fs/fs-writeback.c:2477 > mark_inode_dirty_sync include/linux/fs.h:2410 [inline] > iput+0x1fe/0x930 fs/inode.c:1764 > __dentry_kill+0x20d/0x630 fs/dcache.c:603 > shrink_kill+0xa9/0x2c0 fs/dcache.c:1048 > shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1075 > prune_dcache_sb+0x10f/0x180 fs/dcache.c:1156 > super_cache_scan+0x34f/0x4b0 fs/super.c:221 > do_shrink_slab+0x705/0x1160 mm/shrinker.c:435 > shrink_slab_memcg mm/shrinker.c:548 [inline] > shrink_slab+0x883/0x14d0 mm/shrinker.c:626 > shrink_node_memcgs mm/vmscan.c:5875 [inline] > shrink_node+0x11f5/0x2d60 mm/vmscan.c:5908 > kswapd_shrink_node mm/vmscan.c:6704 [inline] > balance_pgdat mm/vmscan.c:6895 [inline] > kswapd+0x1a25/0x30c0 mm/vmscan.c:7164 > kthread+0x2f0/0x390 kernel/kthread.c:388 > ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > </TASK> > NILFS (loop4): discard dirty page: offset=98304, ino=3 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > NILFS (loop4): discard dirty block: blocknr=0, size=1024 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > NILFS (loop4): discard dirty page: offset=0, ino=12 > NILFS (loop4): discard dirty block: blocknr=17, size=1024 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > NILFS (loop4): discard dirty page: offset=0, ino=3 > NILFS (loop4): discard dirty block: blocknr=42, size=1024 > NILFS (loop4): discard dirty block: blocknr=43, size=1024 > NILFS (loop4): discard dirty block: blocknr=44, size=1024 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > NILFS (loop4): discard dirty page: offset=4096, ino=6 > NILFS (loop4): discard dirty block: blocknr=39, size=1024 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > NILFS (loop4): discard dirty page: offset=196608, ino=3 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > NILFS (loop4): discard dirty block: blocknr=49, size=1024 > NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024 > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup >
