================================================================== BUG: KASAN: use-after-free in __lock_acquire+0x104/0x6800 kernel/locking/lockdep.c:4919 Read of size 8 at addr ffff0000cc8a8bb0 by task gfs2_quotad/4749 CPU: 1 PID: 4749 Comm: gfs2_quotad Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026 Call trace: dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 print_address_description+0x88/0x218 mm/kasan/report.c:316 print_report+0x50/0x68 mm/kasan/report.c:420 kasan_report+0xa8/0xfc mm/kasan/report.c:524 __asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351 __lock_acquire+0x104/0x6800 kernel/locking/lockdep.c:4919 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x6c/0xb0 kernel/locking/spinlock.c:162 finish_wait+0xc8/0x1ac kernel/sched/wait.c:410 gfs2_quotad+0x390/0x500 fs/gfs2/quota.c:1579 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 Allocated by task 5113: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:211 [inline] kmalloc_trace+0x7c/0x94 mm/slab_common.c:1031 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] fat_fill_super+0x12c/0x3d30 fs/fat/inode.c:1625 msdos_fill_super+0x40/0x54 fs/fat/namei_msdos.c:660 mount_bdev+0x264/0x358 fs/super.c:1443 msdos_mount+0x44/0x58 fs/fat/namei_msdos.c:667 legacy_get_tree+0xd4/0x16c fs/fs_context.c:632 vfs_get_tree+0x90/0x274 fs/super.c:1573 do_new_mount+0x228/0x810 fs/namespace.c:3078 path_mount+0x5bc/0xe80 fs/namespace.c:3408 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount fs/namespace.c:3606 [inline] __arm64_sys_mount+0x49c/0x59c fs/namespace.c:3606 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 Freed by task 21: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xbc/0x218 mm/slub.c:3700 kfree+0xd0/0x1a8 mm/slab_common.c:988 delayed_free+0xd4/0xec fs/fat/inode.c:730 rcu_do_batch kernel/rcu/tree.c:2297 [inline] rcu_core+0x828/0x18b0 kernel/rcu/tree.c:2557 rcu_core_si+0x10/0x1c kernel/rcu/tree.c:2574 handle_softirqs+0x318/0xc60 kernel/softirq.c:596 run_ksoftirqd+0x7c/0x2ac kernel/softirq.c:968 smpboot_thread_fn+0x4b0/0x964 kernel/smpboot.c:164 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 Last potentially related work creation: kasan_save_stack+0x40/0x70 mm/kasan/common.c:46 __kasan_record_aux_stack+0xc0/0xdc mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496 call_rcu+0x100/0x94c kernel/rcu/tree.c:2849 fat_put_super+0x98/0xac fs/fat/inode.c:742 generic_shutdown_super+0x130/0x324 fs/super.c:501 kill_block_super+0x70/0xdc fs/super.c:1470 deactivate_locked_super+0xac/0x120 fs/super.c:332 deactivate_super+0xe4/0x104 fs/super.c:363 cleanup_mnt+0x390/0x418 fs/namespace.c:1191 __cleanup_mnt+0x20/0x30 fs/namespace.c:1198 task_work_run+0x1ec/0x278 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] do_notify_resume+0x1fa0/0x2aa4 arch/arm64/kernel/signal.c:1151 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] el0_svc+0x98/0x128 arch/arm64/kernel/entry-common.c:638 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 The buggy address belongs to the object at ffff0000cc8a8000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 2992 bytes inside of 8192-byte region [ffff0000cc8a8000, ffff0000cc8aa000) The buggy address belongs to the physical page: page:0000000055afa129 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10c8a8 head:0000000055afa129 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000010200 fffffc0003788e00 dead000000000005 ffff0000c0002c00 raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000cc8a8a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000cc8a8b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff0000cc8a8b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000cc8a8c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000cc8a8c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== INFO: trying to register non-static key. The code is fine but needs lockdep annotation, or maybe you didn't initialize this object before use? turning off the locking correctness validator. CPU: 1 PID: 4749 Comm: gfs2_quotad Tainted: G B syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026 Call trace: dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 dump_stack+0x1c/0x5c lib/dump_stack.c:113 assign_lock_key+0x230/0x264 kernel/locking/lockdep.c:974 register_lock_class+0x1ac/0x694 kernel/locking/lockdep.c:1287 __lock_acquire+0x164/0x6800 kernel/locking/lockdep.c:4928 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x6c/0xb0 kernel/locking/spinlock.c:162 finish_wait+0xc8/0x1ac kernel/sched/wait.c:410 gfs2_quotad+0x390/0x500 fs/gfs2/quota.c:1579 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 list_del corruption. prev->next should be ffff800021177d98, but was 0000000000000000. (prev=ffff0000cc8a8bd8) ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:61! Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 4749 Comm: gfs2_quotad Tainted: G B syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026 pstate: 624000c5 (nZCv daIF +PAN -UAO +TCO -DIT -SSBS BTYPE=--) pc : __list_del_entry_valid+0x13c/0x158 lib/list_debug.c:59 lr : __list_del_entry_valid+0x13c/0x158 lib/list_debug.c:59 sp : ffff800021177c70 x29: ffff800021177c70 x28: 0000000000000000 x27: 0000000000000bb8 x26: 0000000000001770 x25: dfff800000000000 x24: dfff800000000000 x23: ffff0000cc8a87c0 x22: dfff800000000000 x21: ffff0000cc8a8bd8 x20: ffff0000cc8a8bd8 x19: ffff800021177d98 x18: ffff800011b9bf60 x17: 20747562202c3839 x16: ffff8000082eef80 x15: 0000000000000000 x14: 0000000000000001 x13: 1fffe00033eaa5a3 x12: 0000000000ff0100 x11: ff00800008311668 x10: 0000000000000000 x9 : fa4685daaf885300 x8 : fa4685daaf885300 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff800021177738 x4 : ffff800015304cc0 x3 : ffff800008538848 x2 : 0000000000000001 x1 : 0000000100000001 x0 : 000000000000006d Call trace: __list_del_entry_valid+0x13c/0x158 lib/list_debug.c:59 __list_del_entry include/linux/list.h:134 [inline] list_del_init include/linux/list.h:206 [inline] finish_wait+0xd4/0x1ac kernel/sched/wait.c:411 gfs2_quotad+0x390/0x500 fs/gfs2/quota.c:1579 kthread+0x250/0x2d8 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 Code: 91300000 aa1303e1 aa1503e3 95c1ea98 (d4210000) ---[ end trace 0000000000000000 ]---