================================================================== BUG: KASAN: slab-use-after-free in jfs_readdir+0x118f/0x3ae0 fs/jfs/jfs_dtree.c:2881 Read of size 8 at addr ffff88801e3759f0 by task syz.3.56/6239 CPU: 1 UID: 0 PID: 6239 Comm: syz.3.56 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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: 0033:0x7f3e9780f749 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:00007f3e95a6e038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 00007f3e97a65fa0 RCX: 00007f3e9780f749 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 00007f3e97893f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3e97a66038 R14: 00007f3e97a65fa0 R15: 00007ffdce726d18 Allocated by task 6239: 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:4978 [inline] slab_alloc_node mm/slub.c:5288 [inline] kmem_cache_alloc_noprof+0x181/0x6b0 mm/slub.c:5295 mempool_alloc_noprof+0x1a0/0x4e0 mm/mempool.c:426 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_create+0x6c8/0xa80 fs/jfs/namei.c:137 lookup_open fs/namei.c:3796 [inline] open_last_lookups fs/namei.c:3895 [inline] path_openat+0x1500/0x3840 fs/namei.c:4131 do_filp_open+0x1fa/0x410 fs/namei.c:4161 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 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 6239: 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:2543 [inline] slab_free mm/slub.c:6642 [inline] kmem_cache_free+0x19a/0x910 mm/slub.c:6752 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 ffff88801e3759c0 which belongs to the cache jfs_mp of size 248 The buggy address is located 48 bytes inside of freed 248-byte region [ffff88801e3759c0, ffff88801e375ab8) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1e375 flags: 0x80000000000000(node=0|zone=1) page_type: f5(slab) raw: 0080000000000000 ffff88801df80280 dead000000000122 0000000000000000 raw: 0000000000000000 00000000800d000d 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 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1, tgid 1 (swapper/0), ts 6586243878, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1845 prep_new_page mm/page_alloc.c:1853 [inline] get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3879 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3059 [inline] allocate_slab+0x96/0x350 mm/slub.c:3232 new_slab mm/slub.c:3286 [inline] ___slab_alloc+0xb10/0x1400 mm/slub.c:4655 __slab_alloc+0xc6/0x1f0 mm/slub.c:4778 __slab_alloc_node mm/slub.c:4854 [inline] slab_alloc_node mm/slub.c:5276 [inline] kmem_cache_alloc_noprof+0xec/0x6b0 mm/slub.c:5295 mempool_init_node+0x210/0x4f0 mm/mempool.c:241 mempool_create_node_noprof+0xb8/0x150 mm/mempool.c:304 metapage_init+0xd7/0x150 fs/jfs/jfs_metapage.c:292 init_jfs_fs+0xe4/0x500 fs/jfs/super.c:968 do_one_initcall+0x236/0x820 init/main.c:1283 do_initcall_level+0x104/0x190 init/main.c:1345 do_initcalls+0x59/0xa0 init/main.c:1361 kernel_init_freeable+0x334/0x4b0 init/main.c:1593 page_owner free stack trace missing Memory state around the buggy address: ffff88801e375880: fc 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88801e375900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff88801e375980: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ^ ffff88801e375a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801e375a80: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc 00 ==================================================================