From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp153-166.sina.com.cn (smtp153-166.sina.com.cn [61.135.153.166]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E55232DC330 for ; Tue, 8 Jul 2025 12:41:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=61.135.153.166 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751978514; cv=none; b=mdadAK+1+KaGcocstUK7+oDFf93IRthWg9gM/C/irs1tTo83lz+wPcoGu5wZtXjKoG/vCRTPi8Q5rVGjpkAMQj4Rf8STTrJY3jM8Y7TqwvwLStLD0lm6JkQ2UEshePd3mX6vWegLnQitFGrU5JhnM2t8PD+8wjZRrz0whsOKAbo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751978514; c=relaxed/simple; bh=XwwTrK8ElzeWy5cLaY35qNj7Od/dHrKlTxdO7un4THU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Dyl0WpgIVBQiMm5tO80F45eM5njyxA04YYd9HEa4FloshsrDw7BTLwKz2mgyGbLCx0f/ZI30DuOE6n/lqaF0lCVMOIvUhfBfcTy4cUAyYZ6gk+vqPKGPs3we9fnehlQTW5OPe+OVBUCsKIRiWEj5Wry8UGHUcRmXrww/1EGADPo= ARC-Authentication-Results:i=1; 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Tue, 8 Jul 2025 20:41:35 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 6580446685194 X-SMAIL-UIID: DE2FADE2B98345E8A58AD1E76D04DAE6-20250708-204135-1 From: Hillf Danton To: syzbot Cc: david@redhat.com, gfs2@lists.linux.dev, Matthew Wilcox , Andreas Gruenbacher , linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [gfs2] KASAN: slab-use-after-free Read in move_to_new_folio (4) Date: Tue, 8 Jul 2025 20:41:22 +0800 Message-ID: <20250708124124.2980-1-hdanton@sina.com> In-Reply-To: <686cfef4.050a0220.1ffab7.0005.GAE@google.com> References: Precedence: bulk X-Mailing-List: gfs2@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > Date: Tue, 08 Jul 2025 04:20:20 -0700 > Hello, > > syzbot found the following issue on: > > HEAD commit: d7b8f8e20813 Linux 6.16-rc5 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=15daabd4580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f6cfc97245100778 > dashboard link: https://syzkaller.appspot.com/bug?extid=9f0d09a59e1e92ee7b43 > compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=156df28c580000 > > Downloadable assets: > disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-d7b8f8e2.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/88e0e9607487/vmlinux-d7b8f8e2.xz > kernel image: https://storage.googleapis.com/syzbot-assets/c0e31868d902/bzImage-d7b8f8e2.xz > mounted in repro: https://storage.googleapis.com/syzbot-assets/c8cd0473f7ee/mount_7.gz > fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=111d4a8c580000) > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+9f0d09a59e1e92ee7b43@syzkaller.appspotmail.com > > ================================================================== > BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline] > BUG: KASAN: slab-use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] > BUG: KASAN: slab-use-after-free in mapping_inaccessible include/linux/pagemap.h:336 [inline] > BUG: KASAN: slab-use-after-free in move_to_new_folio+0x182/0x7a0 mm/migrate.c:983 > Read of size 8 at addr ffff8880429ac910 by task kcompactd1/30 > > CPU: 0 UID: 0 PID: 30 Comm: kcompactd1 Not tainted 6.16.0-rc5-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_address_description mm/kasan/report.c:408 [inline] > print_report+0xd2/0x2b0 mm/kasan/report.c:521 > kasan_report+0x118/0x150 mm/kasan/report.c:634 > check_region_inline mm/kasan/generic.c:-1 [inline] > kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:189 > instrument_atomic_read include/linux/instrumented.h:68 [inline] > _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] > mapping_inaccessible include/linux/pagemap.h:336 [inline] Given truncate_inode_pages_final() [1] in gfs2_evict_inode(), it is difficult to understand this mapping uaf. [1] https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/gfs2/super.c?id=d7b8f8e20813#n1441 > move_to_new_folio+0x182/0x7a0 mm/migrate.c:983 > migrate_folio_move mm/migrate.c:1301 [inline] > migrate_folios_move mm/migrate.c:1653 [inline] > migrate_pages_batch+0x1c34/0x2830 mm/migrate.c:1900 > migrate_pages_sync mm/migrate.c:1930 [inline] > migrate_pages+0x1bcc/0x2930 mm/migrate.c:2039 > compact_zone+0x23f4/0x4ad0 mm/compaction.c:2683 > compact_node+0x1d2/0x280 mm/compaction.c:2952 > kcompactd+0xbc8/0x1290 mm/compaction.c:3250 > kthread+0x70e/0x8a0 kernel/kthread.c:464 > ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 > > > Allocated by task 5644: > kasan_save_stack mm/kasan/common.c:47 [inline] > kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 > unpoison_slab_object mm/kasan/common.c:319 [inline] > __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345 > kasan_slab_alloc include/linux/kasan.h:250 [inline] > slab_post_alloc_hook mm/slub.c:4148 [inline] > slab_alloc_node mm/slub.c:4197 [inline] > kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4204 > gfs2_glock_get+0x263/0xec0 fs/gfs2/glock.c:1183 > gfs2_inode_lookup+0x215/0xb10 fs/gfs2/inode.c:135 > gfs2_dir_search+0x168/0x220 fs/gfs2/dir.c:1667 > gfs2_lookupi+0x3d9/0x5a0 fs/gfs2/inode.c:340 > gfs2_jindex_hold fs/gfs2/ops_fstype.c:574 [inline] > init_journal+0x54a/0x2260 fs/gfs2/ops_fstype.c:716 > init_inodes+0xdb/0x320 fs/gfs2/ops_fstype.c:851 > gfs2_fill_super+0x1939/0x20e0 fs/gfs2/ops_fstype.c:1253 > get_tree_bdev_flags+0x40b/0x4d0 fs/super.c:1681 > gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1335 > vfs_get_tree+0x92/0x2b0 fs/super.c:1804 > do_new_mount+0x24a/0xa40 fs/namespace.c:3902 > do_mount fs/namespace.c:4239 [inline] > __do_sys_mount fs/namespace.c:4450 [inline] > __se_sys_mount+0x317/0x410 fs/namespace.c:4427 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Freed by task 15: > kasan_save_stack mm/kasan/common.c:47 [inline] > kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 > kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 > poison_slab_object mm/kasan/common.c:247 [inline] > __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 > kasan_slab_free include/linux/kasan.h:233 [inline] > slab_free_hook mm/slub.c:2381 [inline] > slab_free mm/slub.c:4643 [inline] > kmem_cache_free+0x18f/0x400 mm/slub.c:4745 > rcu_do_batch kernel/rcu/tree.c:2576 [inline] > rcu_core+0xca8/0x1710 kernel/rcu/tree.c:2832 > handle_softirqs+0x286/0x870 kernel/softirq.c:579 > run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968 > smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:164 > kthread+0x70e/0x8a0 kernel/kthread.c:464 > ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 > > Last potentially related work creation: > kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47 > kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548 > __call_rcu_common kernel/rcu/tree.c:3094 [inline] > call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3214 > __gfs2_glock_free+0xb44/0xc90 fs/gfs2/glock.c:172 > gfs2_glock_free+0x3c/0xa0 fs/gfs2/glock.c:178 > gfs2_glock_put_eventually fs/gfs2/super.c:1185 [inline] > gfs2_evict_inode+0xae7/0x1000 fs/gfs2/super.c:1460 > evict+0x501/0x9c0 fs/inode.c:810 > gfs2_jindex_free+0x39c/0x440 fs/gfs2/super.c:79 > init_journal+0x8f1/0x2260 fs/gfs2/ops_fstype.c:833 > init_inodes+0xdb/0x320 fs/gfs2/ops_fstype.c:851 > gfs2_fill_super+0x1939/0x20e0 fs/gfs2/ops_fstype.c:1253 > get_tree_bdev_flags+0x40b/0x4d0 fs/super.c:1681 > gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1335 > vfs_get_tree+0x92/0x2b0 fs/super.c:1804 > do_new_mount+0x24a/0xa40 fs/namespace.c:3902 > do_mount fs/namespace.c:4239 [inline] > __do_sys_mount fs/namespace.c:4450 [inline] > __se_sys_mount+0x317/0x410 fs/namespace.c:4427 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Second to last potentially related work creation: > kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47 > kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548 > insert_work+0x3d/0x330 kernel/workqueue.c:2183 > __queue_work+0xcfc/0xfe0 kernel/workqueue.c:2341 > queue_delayed_work_on+0x18b/0x280 kernel/workqueue.c:2561 > queue_delayed_work include/linux/workqueue.h:677 [inline] > gfs2_glock_queue_work fs/gfs2/glock.c:250 [inline] > do_xmote+0xce0/0x1220 fs/gfs2/glock.c:839 > glock_work_func+0x2a8/0x580 fs/gfs2/glock.c:1096 > process_one_work kernel/workqueue.c:3238 [inline] > process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 > worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 > kthread+0x70e/0x8a0 kernel/kthread.c:464 > ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 > > The buggy address belongs to the object at ffff8880429ac548 > which belongs to the cache gfs2_glock(aspace) of size 1224 > The buggy address is located 968 bytes inside of > freed 1224-byte region [ffff8880429ac548, ffff8880429aca10) > > The buggy address belongs to the physical page: > page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880429acfd8 pfn:0x429ac > head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 > flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff) > page_type: f5(slab) > raw: 04fff00000000040 ffff8880327f2640 ffffea000110bf00 0000000000000002 > raw: ffff8880429acfd8 00000000000c0008 00000000f5000000 0000000000000000 > head: 04fff00000000040 ffff8880327f2640 ffffea000110bf00 0000000000000002 > head: ffff8880429acfd8 00000000000c0008 00000000f5000000 0000000000000000 > head: 04fff00000000002 ffffea00010a6b01 00000000ffffffff 00000000ffffffff > head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 > page dumped because: kasan: bad access detected > page_owner tracks the page as allocated > page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5547, tgid 5547 (syz.0.16), ts 128645082054, free_ts 128606732548 > set_page_owner include/linux/page_owner.h:32 [inline] > post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704 > prep_new_page mm/page_alloc.c:1712 [inline] > get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669 > __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959 > alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419 > alloc_slab_page mm/slub.c:2451 [inline] > allocate_slab+0x8a/0x3b0 mm/slub.c:2619 > new_slab mm/slub.c:2673 [inline] > ___slab_alloc+0xbfc/0x1480 mm/slub.c:3859 > __slab_alloc mm/slub.c:3949 [inline] > __slab_alloc_node mm/slub.c:4024 [inline] > slab_alloc_node mm/slub.c:4185 [inline] > kmem_cache_alloc_noprof+0x283/0x3c0 mm/slub.c:4204 > gfs2_glock_get+0x263/0xec0 fs/gfs2/glock.c:1183 > gfs2_inode_lookup+0x215/0xb10 fs/gfs2/inode.c:135 > gfs2_lookup_root fs/gfs2/ops_fstype.c:425 [inline] > init_sb+0xa30/0x12c0 fs/gfs2/ops_fstype.c:494 > gfs2_fill_super+0x1605/0x20e0 fs/gfs2/ops_fstype.c:1220 > get_tree_bdev_flags+0x40b/0x4d0 fs/super.c:1681 > gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1335 > vfs_get_tree+0x92/0x2b0 fs/super.c:1804 > do_new_mount+0x24a/0xa40 fs/namespace.c:3902 > do_mount fs/namespace.c:4239 [inline] > __do_sys_mount fs/namespace.c:4450 [inline] > __se_sys_mount+0x317/0x410 fs/namespace.c:4427 > page last free pid 5547 tgid 5547 stack trace: > reset_page_owner include/linux/page_owner.h:25 [inline] > free_pages_prepare mm/page_alloc.c:1248 [inline] > __free_frozen_pages+0xc71/0xe70 mm/page_alloc.c:2706 > stack_depot_save_flags+0x445/0x900 lib/stackdepot.c:678 > kasan_save_stack mm/kasan/common.c:48 [inline] > kasan_save_track+0x4f/0x80 mm/kasan/common.c:68 > unpoison_slab_object mm/kasan/common.c:319 [inline] > __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345 > kasan_slab_alloc include/linux/kasan.h:250 [inline] > slab_post_alloc_hook mm/slub.c:4148 [inline] > slab_alloc_node mm/slub.c:4197 [inline] > kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4204 > __kernfs_new_node+0xd7/0x7e0 fs/kernfs/dir.c:637 > kernfs_new_node+0x102/0x210 fs/kernfs/dir.c:713 > kernfs_create_dir_ns+0x44/0x130 fs/kernfs/dir.c:1083 > sysfs_create_dir_ns+0x123/0x280 fs/sysfs/dir.c:59 > create_dir lib/kobject.c:73 [inline] > kobject_add_internal+0x59f/0xb40 lib/kobject.c:240 > kobject_add_varg lib/kobject.c:374 [inline] > kobject_init_and_add+0x125/0x190 lib/kobject.c:457 > gfs2_sys_fs_add+0x234/0x450 fs/gfs2/sys.c:737 > gfs2_fill_super+0x13d6/0x20e0 fs/gfs2/ops_fstype.c:1206 > get_tree_bdev_flags+0x40b/0x4d0 fs/super.c:1681 > gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1335 > vfs_get_tree+0x92/0x2b0 fs/super.c:1804 > > Memory state around the buggy address: > ffff8880429ac800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8880429ac880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > >ffff8880429ac900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8880429ac980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8880429aca00: fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ================================================================== > > > --- > 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@googlegroups.com. > > 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 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. > > 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 >