================================================================== BUG: KASAN: slab-use-after-free in __list_lru_walk_one+0xfb/0x420 mm/list_lru.c:293 Read of size 8 at addr ffff88807b39a1c8 by task syz.6.2667/15481 CPU: 0 UID: 0 PID: 15481 Comm: syz.6.2667 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0xe8/0x150 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 __list_lru_walk_one+0xfb/0x420 mm/list_lru.c:293 list_lru_walk_one+0x3c/0x50 mm/list_lru.c:341 list_lru_shrink_walk include/linux/list_lru.h:262 [inline] gfs2_qd_shrink_scan+0x155/0x330 fs/gfs2/quota.c:182 do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437 shrink_slab+0xd74/0x10d0 mm/shrinker.c:664 drop_slab_node mm/vmscan.c:434 [inline] drop_slab+0x14b/0x290 mm/vmscan.c:452 drop_caches_sysctl_handler+0xc7/0x170 fs/drop_caches.c:68 proc_sys_call_handler+0x4cb/0x700 fs/proc/proc_sysctl.c:600 do_iter_readv_writev+0x623/0x8c0 fs/read_write.c:-1 vfs_writev+0x31a/0x960 fs/read_write.c:1057 do_writev+0x14d/0x2d0 fs/read_write.c:1103 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6da778f749 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:00007f6da8552038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007f6da79e5fa0 RCX: 00007f6da778f749 RDX: 0000000000000001 RSI: 00002000000000c0 RDI: 0000000000000003 RBP: 00007f6da7813f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6da79e6038 R14: 00007f6da79e5fa0 R15: 00007ffe53fe8718 Allocated by task 15210: 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:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5270 qd_alloc+0x50/0x250 fs/gfs2/quota.c:234 gfs2_quota_init+0x762/0x1200 fs/gfs2/quota.c:1448 gfs2_make_fs_rw+0x143/0x220 fs/gfs2/super.c:149 gfs2_fill_super+0x1b6a/0x21b0 fs/gfs2/ops_fstype.c:1275 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691 gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1332 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+0x302/0xa10 fs/namespace.c:3712 do_mount fs/namespace.c:4035 [inline] __do_sys_mount fs/namespace.c:4224 [inline] __se_sys_mount+0x313/0x410 fs/namespace.c:4201 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 0: 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:6670 [inline] kmem_cache_free+0x197/0x620 mm/slub.c:6781 gfs2_qd_dealloc+0x70/0xe0 fs/gfs2/quota.c:111 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0xc8e/0x1720 kernel/rcu/tree.c:2857 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 __call_rcu_common kernel/rcu/tree.c:3119 [inline] call_rcu+0xee/0x890 kernel/rcu/tree.c:3239 qd_ungrab_sync fs/gfs2/quota.c:493 [inline] gfs2_quota_sync+0x30c/0x460 fs/gfs2/quota.c:1351 gfs2_sync_fs+0x4c/0xb0 fs/gfs2/super.c:658 __iterate_supers+0x13d/0x290 fs/super.c:924 ksys_sync+0xb2/0x150 fs/sync.c:104 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88807b39a150 which belongs to the cache gfs2_quotad of size 272 The buggy address is located 120 bytes inside of freed 272-byte region [ffff88807b39a150, ffff88807b39a260) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88807b39a000 pfn:0x7b39a flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff8881416d0140 dead000000000122 0000000000000000 raw: ffff88807b39a000 00000000800c000b 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Reclaimable, gfp_mask 0x52c50(GFP_NOFS|__GFP_RECLAIMABLE|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 6461, tgid 6460 (syz.4.129), ts 138148850697, free_ts 121351328536 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857 prep_new_page mm/page_alloc.c:1865 [inline] get_page_from_freelist+0x24e0/0x2580 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab+0x86/0x3b0 mm/slub.c:3248 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xe53/0x1820 mm/slub.c:4656 __slab_alloc+0x65/0x100 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] kmem_cache_alloc_noprof+0x40f/0x710 mm/slub.c:5270 qd_alloc+0x50/0x250 fs/gfs2/quota.c:234 gfs2_quota_init+0x762/0x1200 fs/gfs2/quota.c:1448 gfs2_make_fs_rw+0x143/0x220 fs/gfs2/super.c:149 gfs2_fill_super+0x1b6a/0x21b0 fs/gfs2/ops_fstype.c:1275 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691 gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1332 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+0x302/0xa10 fs/namespace.c:3712 page last free pid 5924 tgid 5924 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943 __slab_free+0x2ce/0x320 mm/slub.c:6004 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] __kmalloc_cache_noprof+0x37c/0x700 mm/slub.c:5771 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] nsim_fib6_rt_create drivers/net/netdevsim/fib.c:547 [inline] nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline] nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline] nsim_fib_event+0xc88/0x8960 drivers/net/netdevsim/fib.c:889 nsim_fib_event_work+0x249/0x3b0 drivers/net/netdevsim/fib.c:1493 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Memory state around the buggy address: ffff88807b39a080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807b39a100: fb fb fc fc fc fc fc fc fc fc fa fb fb fb fb fb >ffff88807b39a180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807b39a200: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff88807b39a280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================