================================================================== BUG: KASAN: slab-use-after-free in rht_key_hashfn include/linux/rhashtable.h:159 [inline] BUG: KASAN: slab-use-after-free in rht_head_hashfn include/linux/rhashtable.h:174 [inline] BUG: KASAN: slab-use-after-free in __rhashtable_remove_fast_one include/linux/rhashtable.h:1053 [inline] BUG: KASAN: slab-use-after-free in __rhashtable_remove_fast include/linux/rhashtable.h:1139 [inline] BUG: KASAN: slab-use-after-free in rhashtable_remove_fast include/linux/rhashtable.h:1168 [inline] BUG: KASAN: slab-use-after-free in xfs_buf_rele_cached fs/xfs/xfs_buf.c:923 [inline] BUG: KASAN: slab-use-after-free in xfs_buf_rele+0x914/0xf80 fs/xfs/xfs_buf.c:948 Read of size 4 at addr ffff888061a84c08 by task syz.2.538/31062 CPU: 1 UID: 0 PID: 31062 Comm: syz.2.538 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 rht_key_hashfn include/linux/rhashtable.h:159 [inline] rht_head_hashfn include/linux/rhashtable.h:174 [inline] __rhashtable_remove_fast_one include/linux/rhashtable.h:1053 [inline] __rhashtable_remove_fast include/linux/rhashtable.h:1139 [inline] rhashtable_remove_fast include/linux/rhashtable.h:1168 [inline] xfs_buf_rele_cached fs/xfs/xfs_buf.c:923 [inline] xfs_buf_rele+0x914/0xf80 fs/xfs/xfs_buf.c:948 xfs_buftarg_shrink_scan+0x24a/0x2e0 fs/xfs/xfs_buf.c:1650 do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437 shrink_slab+0xdf2/0x1150 mm/shrinker.c:664 drop_slab_node mm/vmscan.c:434 [inline] drop_slab+0x14a/0x290 mm/vmscan.c:452 drop_caches_sysctl_handler+0xc7/0x170 fs/drop_caches.c:68 proc_sys_call_handler+0x4c9/0x830 fs/proc/proc_sysctl.c:600 do_iter_readv_writev+0x62b/0x8d0 fs/read_write.c:-1 vfs_writev+0x345/0x9a0 fs/read_write.c:1057 do_writev+0x15a/0x2e0 fs/read_write.c:1103 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdf2433af79 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:00007fdf2256d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007fdf245b6090 RCX: 00007fdf2433af79 RDX: 0000000000000001 RSI: 00002000000000c0 RDI: 0000000000000007 RBP: 00007fdf243d16e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdf245b6128 R14: 00007fdf245b6090 R15: 00007ffd71ff4ce8 Allocated by task 31057: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5657 [inline] __kvmalloc_node_noprof+0x3d2/0x8f0 mm/slub.c:7144 bucket_table_alloc lib/rhashtable.c:186 [inline] rhashtable_init_noprof+0x536/0xa80 lib/rhashtable.c:1075 xfs_perag_alloc fs/xfs/libxfs/xfs_ag.c:238 [inline] xfs_initialize_perag+0x284/0x630 fs/xfs/libxfs/xfs_ag.c:279 xfs_mountfs+0xaf2/0x22e0 fs/xfs/xfs_mount.c:995 xfs_fs_fill_super+0x11c3/0x1610 fs/xfs/xfs_super.c:1960 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1691 vfs_get_tree+0x92/0x2a0 fs/super.c:1751 fc_mount fs/namespace.c:1199 [inline] do_new_mount_fc fs/namespace.c:3636 [inline] do_new_mount+0x329/0xa50 fs/namespace.c:3712 do_mount fs/namespace.c:4035 [inline] __do_sys_mount fs/namespace.c:4224 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4201 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 27122: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 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:2540 [inline] slab_free mm/slub.c:6674 [inline] kfree+0x1bb/0x8f0 mm/slub.c:6886 rhashtable_free_and_destroy+0x7e8/0x940 lib/rhashtable.c:1173 xfs_group_free+0x166/0x370 fs/xfs/libxfs/xfs_group.c:171 xfs_free_perag_range+0x36/0x60 fs/xfs/libxfs/xfs_ag.c:133 xfs_unmountfs+0x2db/0x320 fs/xfs/xfs_mount.c:1360 xfs_fs_put_super+0x65/0x160 fs/xfs/xfs_super.c:1254 generic_shutdown_super+0x135/0x2c0 fs/super.c:643 kill_block_super+0x44/0x90 fs/super.c:1722 xfs_kill_sb+0x15/0x50 fs/xfs/xfs_super.c:2297 deactivate_locked_super+0xbc/0x130 fs/super.c:474 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1318 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:44 [inline] exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888061a84c00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 8 bytes inside of freed 512-byte region [ffff888061a84c00, ffff888061a84e00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x61a84 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x80000000000040(head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000040 ffff88813fe26c80 ffffea0001790e00 dead000000000002 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813fe26c80 ffffea0001790e00 dead000000000002 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 0080000000000002 ffffea000186a101 00000000ffffffff 00000000ffffffff head: 0000000000000000 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 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1018, tgid 1018 (kworker/u8:6), ts 89684971173, free_ts 89522419911 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884 prep_new_page mm/page_alloc.c:1892 [inline] get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3945 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab+0x86/0x3a0 mm/slub.c:3248 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xaf8/0x13d0 mm/slub.c:4656 __slab_alloc+0xc5/0x1f0 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __kmalloc_cache_noprof+0x100/0x6b0 mm/slub.c:5775 kmalloc_noprof include/linux/slab.h:957 [inline] batadv_forw_packet_alloc+0x1e9/0x390 net/batman-adv/send.c:506 batadv_iv_ogm_aggregate_new net/batman-adv/bat_iv_ogm.c:570 [inline] batadv_iv_ogm_queue_add+0x845/0xd20 net/batman-adv/bat_iv_ogm.c:677 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:854 [inline] batadv_iv_ogm_schedule+0xb1f/0xf60 net/batman-adv/bat_iv_ogm.c:873 batadv_iv_send_outstanding_bat_ogm_packet+0x6c8/0x7e0 net/batman-adv/bat_iv_ogm.c:1709 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 page last free pid 5800 tgid 5800 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0xfd0/0x1160 mm/page_alloc.c:2973 stack_depot_save_flags+0x40e/0x810 lib/stackdepot.c:727 kasan_save_stack mm/kasan/common.c:58 [inline] kasan_save_track+0x4f/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5657 [inline] __kmalloc_node_noprof+0x396/0x800 mm/slub.c:5663 kmalloc_array_node_noprof include/linux/slab.h:1075 [inline] alloc_slab_obj_exts+0x3e/0x100 mm/slub.c:2123 account_slab mm/slub.c:3202 [inline] allocate_slab+0x1cc/0x3a0 mm/slub.c:3267 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xaf8/0x13d0 mm/slub.c:4656 __slab_alloc+0xc5/0x1f0 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] kmem_cache_alloc_lru_noprof+0x103/0x6a0 mm/slub.c:5282 __d_alloc+0x37/0x6f0 fs/dcache.c:1740 d_alloc+0x4b/0x190 fs/dcache.c:1819 lookup_one_qstr_excl+0xdc/0x360 fs/namei.c:1751 __start_dirop fs/namei.c:2875 [inline] start_dirop+0x5c/0x90 fs/namei.c:2884 simple_start_creating+0xcc/0x110 fs/libfs.c:2330 debugfs_start_creating+0xdb/0x1a0 fs/debugfs/inode.c:394 Memory state around the buggy address: ffff888061a84b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888061a84b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888061a84c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888061a84c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888061a84d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 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