================================================================== BUG: KASAN: slab-use-after-free in jfs_readdir+0x10a8/0x33f0 fs/jfs/jfs_dtree.c:2878 Read of size 8 at addr ffff88801c7323d8 by task syz.3.1488/19463 CPU: 1 UID: 0 PID: 19463 Comm: syz.3.1488 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 jfs_readdir+0x10a8/0x33f0 fs/jfs/jfs_dtree.c:2878 wrap_directory_iterator+0x99/0xe0 fs/readdir.c:67 iterate_dir+0x2f1/0x4e0 fs/readdir.c:110 __do_sys_getdents64 fs/readdir.c:399 [inline] __se_sys_getdents64+0xf1/0x280 fs/readdir.c:384 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5b90ecce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f5b8f11e028 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 00007f5b91145fa0 RCX: 00007f5b90ecce59 RDX: 0000000000000063 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 00007f5b90f62d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5b91146038 R14: 00007f5b91145fa0 R15: 00007fff0ff35b68 Allocated by task 19463: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4610 [inline] slab_alloc_node mm/slub.c:4939 [inline] kmem_cache_alloc_noprof+0x337/0x680 mm/slub.c:4946 mempool_alloc_noprof+0x1c5/0x300 mm/mempool.c:559 alloc_metapage fs/jfs/jfs_metapage.c:264 [inline] __get_metapage+0x4ed/0xdf0 fs/jfs/jfs_metapage.c:761 dtSplitRoot+0x216/0x1900 fs/jfs/jfs_dtree.c:1907 dtSplitUp fs/jfs/jfs_dtree.c:990 [inline] dtInsert+0xedd/0x5cb0 fs/jfs/jfs_dtree.c:868 jfs_mkdir+0x76b/0xb00 fs/jfs/namei.c:271 vfs_mkdir+0x402/0x620 fs/namei.c:5272 filename_mkdirat+0x289/0x520 fs/namei.c:5305 __do_sys_mkdir fs/namei.c:5332 [inline] __se_sys_mkdir+0x34/0x150 fs/namei.c:5329 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 19463: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2700 [inline] slab_free mm/slub.c:6310 [inline] kmem_cache_free+0x187/0x6c0 mm/slub.c:6437 mempool_free+0xf5/0x140 mm/mempool.c:704 free_metapage fs/jfs/jfs_metapage.c:280 [inline] drop_metapage fs/jfs/jfs_metapage.c:317 [inline] release_metapage+0x7eb/0xa50 fs/jfs/jfs_metapage.c:893 dtReadNext fs/jfs/jfs_dtree.c:3199 [inline] jfs_readdir+0xe35/0x33f0 fs/jfs/jfs_dtree.c:2871 wrap_directory_iterator+0x99/0xe0 fs/readdir.c:67 iterate_dir+0x2f1/0x4e0 fs/readdir.c:110 __do_sys_getdents64 fs/readdir.c:399 [inline] __se_sys_getdents64+0xf1/0x280 fs/readdir.c:384 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88801c7323a8 which belongs to the cache jfs_mp of size 248 The buggy address is located 48 bytes inside of freed 248-byte region [ffff88801c7323a8, ffff88801c7324a0) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1c732 flags: 0x80000000000000(node=0|zone=1) page_type: f5(slab) raw: 0080000000000000 ffff888140ad3dc0 dead000000000100 dead000000000122 raw: 0000000000000000 00000008000d000d 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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 4496286429, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853 prep_new_page mm/page_alloc.c:1861 [inline] get_page_from_freelist+0x2877/0x28f0 mm/page_alloc.c:3941 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221 alloc_slab_page mm/slub.c:3289 [inline] allocate_slab+0x74/0x5d0 mm/slub.c:3404 new_slab mm/slub.c:3447 [inline] refill_objects+0x32b/0x3c0 mm/slub.c:7241 refill_sheaf mm/slub.c:2827 [inline] __pcs_replace_empty_main+0x335/0x6a0 mm/slub.c:4692 alloc_from_pcs mm/slub.c:4790 [inline] slab_alloc_node mm/slub.c:4924 [inline] kmem_cache_alloc_noprof+0x42f/0x680 mm/slub.c:4946 mempool_init_node+0x21f/0x500 mm/mempool.c:259 mempool_create_node_noprof+0xb8/0x150 mm/mempool.c:323 metapage_init+0xed/0x150 fs/jfs/jfs_metapage.c:293 init_jfs_fs+0xfd/0x4e0 fs/jfs/super.c:969 do_one_initcall+0x250/0x870 init/main.c:1347 do_initcall_level+0x10a/0x1a0 init/main.c:1409 do_initcalls+0x59/0xa0 init/main.c:1425 kernel_init_freeable+0x29d/0x3e0 init/main.c:1658 kernel_init+0x1d/0x1d0 init/main.c:1548 page_owner free stack trace missing Memory state around the buggy address: ffff88801c732280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88801c732300: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc >ffff88801c732380: fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb ^ ffff88801c732400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801c732480: fb fb fb fb fc fc fc fc fc fc fc fc fa fb fb fb ==================================================================