================================================================== BUG: KASAN: slab-use-after-free in jfs_readdir+0x460f/0x47a0 fs/jfs/jfs_dtree.c:2881 Read of size 8 at addr ffff888077f0d220 by task syz.5.6/6016 CPU: 0 UID: 0 PID: 6016 Comm: syz.5.6 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 jfs_readdir+0x460f/0x47a0 fs/jfs/jfs_dtree.c:2881 wrap_directory_iterator+0xa2/0xe0 fs/readdir.c:65 iterate_dir+0x296/0xaf0 fs/readdir.c:108 __do_sys_getdents fs/readdir.c:326 [inline] __se_sys_getdents fs/readdir.c:312 [inline] __x64_sys_getdents+0x13c/0x2b0 fs/readdir.c:312 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f911338eba9 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:00007f91141fa038 EFLAGS: 00000246 ORIG_RAX: 000000000000004e RAX: ffffffffffffffda RBX: 00007f91135d5fa0 RCX: 00007f911338eba9 RDX: fffffffffffffd90 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 00007f9113411e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f91135d6038 R14: 00007f91135d5fa0 R15: 00007ffe746be798 Allocated by task 6016: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:330 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:356 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4191 [inline] slab_alloc_node mm/slub.c:4240 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4247 mempool_alloc_noprof+0x179/0x390 mm/mempool.c:406 alloc_metapage fs/jfs/jfs_metapage.c:264 [inline] __get_metapage+0x7c5/0x1080 fs/jfs/jfs_metapage.c:760 dtSplitRoot+0x29f/0x1750 fs/jfs/jfs_dtree.c:1910 dtSplitUp+0x12a2/0x5970 fs/jfs/jfs_dtree.c:993 dtInsert+0x8dd/0xb60 fs/jfs/jfs_dtree.c:871 jfs_symlink+0x738/0x10e0 fs/jfs/namei.c:1020 vfs_symlink fs/namei.c:4730 [inline] vfs_symlink+0x403/0x680 fs/namei.c:4714 do_symlinkat+0x261/0x310 fs/namei.c:4756 __do_sys_symlink fs/namei.c:4777 [inline] __se_sys_symlink fs/namei.c:4775 [inline] __x64_sys_symlink+0x75/0x90 fs/namei.c:4775 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6016: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2422 [inline] slab_free mm/slub.c:4695 [inline] kmem_cache_free+0x2d1/0x4d0 mm/slub.c:4797 mempool_free+0x102/0x750 mm/mempool.c:576 free_metapage fs/jfs/jfs_metapage.c:279 [inline] drop_metapage fs/jfs/jfs_metapage.c:316 [inline] release_metapage+0x47d/0x880 fs/jfs/jfs_metapage.c:892 dtReadNext fs/jfs/jfs_dtree.c:3202 [inline] jfs_readdir+0x2bf9/0x47a0 fs/jfs/jfs_dtree.c:2874 wrap_directory_iterator+0xa2/0xe0 fs/readdir.c:65 iterate_dir+0x296/0xaf0 fs/readdir.c:108 __do_sys_getdents fs/readdir.c:326 [inline] __se_sys_getdents fs/readdir.c:312 [inline] __x64_sys_getdents+0x13c/0x2b0 fs/readdir.c:312 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888077f0d1f0 which belongs to the cache jfs_mp of size 184 The buggy address is located 48 bytes inside of freed 184-byte region [ffff888077f0d1f0, ffff888077f0d2a8) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x77f0d flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801fb88b40 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080100010 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 6016, tgid 6015 (syz.5.6), ts 115920745344, free_ts 115880806158 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2492 [inline] allocate_slab mm/slub.c:2660 [inline] new_slab+0x247/0x330 mm/slub.c:2714 ___slab_alloc+0xcf2/0x1750 mm/slub.c:3901 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3992 __slab_alloc_node mm/slub.c:4067 [inline] slab_alloc_node mm/slub.c:4228 [inline] kmem_cache_alloc_noprof+0xef/0x3b0 mm/slub.c:4247 mempool_alloc_noprof+0x179/0x390 mm/mempool.c:406 alloc_metapage fs/jfs/jfs_metapage.c:264 [inline] __get_metapage+0x7c5/0x1080 fs/jfs/jfs_metapage.c:760 diIAGRead.isra.0+0xcd/0x140 fs/jfs/jfs_imap.c:2672 diAlloc+0x42b/0x1a80 fs/jfs/jfs_imap.c:1392 ialloc+0x84/0x9e0 fs/jfs/jfs_inode.c:56 jfs_symlink+0x26e/0x10e0 fs/jfs/namei.c:917 vfs_symlink fs/namei.c:4730 [inline] vfs_symlink+0x403/0x680 fs/namei.c:4714 do_symlinkat+0x261/0x310 fs/namei.c:4756 page last free pid 1321 tgid 1321 stack trace: create_dummy_stack mm/page_owner.c:94 [inline] register_dummy_stack+0x89/0xd0 mm/page_owner.c:100 init_page_owner+0x48/0x7e0 mm/page_owner.c:118 invoke_init_callbacks mm/page_ext.c:148 [inline] page_ext_init+0x703/0xb00 mm/page_ext.c:486 mm_core_init+0x13c/0x220 mm/mm_init.c:2789 Memory state around the buggy address: ffff888077f0d100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888077f0d180: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fa fb >ffff888077f0d200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888077f0d280: fb fb fb fb fb fc fc fc fc fc fc fc fc 00 00 00 ffff888077f0d300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================