================================================================== BUG: KASAN: slab-use-after-free in jfs_readdir+0x118f/0x3ae0 fs/jfs/jfs_dtree.c:2881 Read of size 8 at addr ffff8880381cf168 by task syz.2.176/7160 CPU: 0 UID: 0 PID: 7160 Comm: syz.2.176 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 jfs_readdir+0x118f/0x3ae0 fs/jfs/jfs_dtree.c:2881 wrap_directory_iterator+0x99/0xe0 fs/readdir.c:65 iterate_dir+0x3a5/0x580 fs/readdir.c:108 __do_sys_getdents64 fs/readdir.c:410 [inline] __se_sys_getdents64+0xe4/0x260 fs/readdir.c:396 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 RIP: 0033:0x7f36d2ddeec9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f36d1004038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 00007f36d3036180 RCX: 00007f36d2ddeec9 RDX: 0000000000000022 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 00007f36d2e61f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f36d3036218 R14: 00007f36d3036180 R15: 00007ffd55a6efc8 Allocated by task 7128: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4946 [inline] slab_alloc_node mm/slub.c:5245 [inline] kmem_cache_alloc_noprof+0x181/0x6b0 mm/slub.c:5252 mempool_alloc_noprof+0x19d/0x4e0 mm/mempool.c:406 alloc_metapage fs/jfs/jfs_metapage.c:264 [inline] __get_metapage+0x509/0xde0 fs/jfs/jfs_metapage.c:760 dtSplitRoot+0x202/0x16c0 fs/jfs/jfs_dtree.c:1910 dtSplitUp fs/jfs/jfs_dtree.c:993 [inline] dtInsert+0xef8/0x5f40 fs/jfs/jfs_dtree.c:871 jfs_mkdir+0x6ec/0xa70 fs/jfs/namei.c:270 vfs_mkdir+0x306/0x510 fs/namei.c:4453 do_mkdirat+0x247/0x590 fs/namei.c:4486 __do_sys_mkdirat fs/namei.c:4503 [inline] __se_sys_mkdirat fs/namei.c:4501 [inline] __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4501 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 Freed by task 7160: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2514 [inline] slab_free mm/slub.c:6566 [inline] kmem_cache_free+0x19a/0x910 mm/slub.c:6676 free_metapage fs/jfs/jfs_metapage.c:279 [inline] drop_metapage fs/jfs/jfs_metapage.c:316 [inline] release_metapage+0x84c/0xab0 fs/jfs/jfs_metapage.c:892 dtReadNext fs/jfs/jfs_dtree.c:3202 [inline] jfs_readdir+0xece/0x3ae0 fs/jfs/jfs_dtree.c:2874 wrap_directory_iterator+0x99/0xe0 fs/readdir.c:65 iterate_dir+0x3a5/0x580 fs/readdir.c:108 __do_sys_getdents64 fs/readdir.c:410 [inline] __se_sys_getdents64+0xe4/0x260 fs/readdir.c:396 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 The buggy address belongs to the object at ffff8880381cf138 which belongs to the cache jfs_mp of size 248 The buggy address is located 48 bytes inside of freed 248-byte region [ffff8880381cf138, ffff8880381cf230) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880381cfea0 pfn:0x381cf anon flags: 0x80000000000000(node=0|zone=1) page_type: f5(slab) raw: 0080000000000000 ffff888146eed780 0000000000000000 0000000000000001 raw: ffff8880381cfea0 00000000800d000c 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5804, tgid 5804 (syz-executor), ts 109281841531, free_ts 109184642759 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3030 [inline] allocate_slab+0x96/0x3a0 mm/slub.c:3203 new_slab mm/slub.c:3257 [inline] ___slab_alloc+0xb12/0x1470 mm/slub.c:4627 __slab_alloc+0xc6/0x1f0 mm/slub.c:4746 __slab_alloc_node mm/slub.c:4822 [inline] slab_alloc_node mm/slub.c:5233 [inline] kmem_cache_alloc_noprof+0xec/0x6b0 mm/slub.c:5252 mempool_alloc_noprof+0x19d/0x4e0 mm/mempool.c:406 alloc_metapage fs/jfs/jfs_metapage.c:264 [inline] __get_metapage+0x509/0xde0 fs/jfs/jfs_metapage.c:760 diWriteSpecial+0x1b4/0x460 fs/jfs/jfs_imap.c:518 diSync+0x69d/0x8d0 fs/jfs/jfs_imap.c:251 diUnmount+0xc8/0x130 fs/jfs/jfs_imap.c:185 jfs_umount+0x1d7/0x3c0 fs/jfs/jfs_umount.c:72 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194 generic_shutdown_super+0x132/0x2c0 fs/super.c:642 page last free pid 5904 tgid 5904 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xfb6/0x1140 mm/page_alloc.c:2906 __slab_free+0x2c6/0x370 mm/slub.c:5923 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4946 [inline] slab_alloc_node mm/slub.c:5245 [inline] kmem_cache_alloc_node_noprof+0x23b/0x6e0 mm/slub.c:5297 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:660 alloc_skb include/linux/skbuff.h:1383 [inline] mld_newpack+0x13c/0xc40 net/ipv6/mcast.c:1775 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1886 add_grec+0x1452/0x1740 net/ipv6/mcast.c:2025 mld_send_cr net/ipv6/mcast.c:2148 [inline] mld_ifc_work+0x6ed/0xd60 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4b9/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff8880381cf000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880381cf080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc >ffff8880381cf100: fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb ^ ffff8880381cf180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880381cf200: fb fb fb fb fb fb fc fc fc fc fc fc fc fc 00 00 ==================================================================