syzbot

==================================================================
BUG: KASAN: slab-use-after-free in __list_lru_walk_one+0xfb/0x420 mm/list_lru.c:293
Read of size 8 at addr ffff8880691fc078 by task syz.0.2200/14240

CPU: 0 UID: 0 PID: 14240 Comm: syz.0.2200 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <TASK>
 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
 __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+0x15d/0x340 fs/gfs2/quota.c:182
 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+0x4c8/0x830 fs/proc/proc_sysctl.c:600
 do_iter_readv_writev+0x619/0x8c0 fs/read_write.c:-1
 vfs_writev+0x33c/0x990 fs/read_write.c:1057
 do_writev+0x154/0x2e0 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: 0033:0x7f12b159aeb9
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:00007f12b24d5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f12b1815fa0 RCX: 00007f12b159aeb9
RDX: 0000000000000001 RSI: 00002000000000c0 RDI: 0000000000000004
RBP: 00007f12b1608c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f12b1816038 R14: 00007f12b1815fa0 R15: 00007ffe8cd05558
 </TASK>

Allocated by task 12340:
 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+0x370/0x6e0 mm/slub.c:5270
 qd_alloc+0x50/0x250 fs/gfs2/quota.c:234
 gfs2_quota_init+0x786/0x1220 fs/gfs2/quota.c:1448
 gfs2_make_fs_rw+0x143/0x220 fs/gfs2/super.c:149
 gfs2_fill_super+0x1b9a/0x21d0 fs/gfs2/ops_fstype.c:1275
 get_tree_bdev_flags+0x431/0x4f0 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+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 11720:
 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]
 kmem_cache_free+0x195/0x610 mm/slub.c:6785
 gfs2_qd_dealloc+0x70/0xe0 fs/gfs2/quota.c:111
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core+0xc9e/0x1750 kernel/rcu/tree.c:2857
 handle_softirqs+0x22a/0x7c0 kernel/softirq.c:622
 do_softirq+0x76/0xd0 kernel/softirq.c:523
 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 napi_threaded_poll_loop+0x63e/0x940 net/core/dev.c:7818
 napi_threaded_poll+0x298/0x3b0 net/core/dev.c:7851
 kthread+0x726/0x8b0 kernel/kthread.c:463
 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

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+0x322/0x470 fs/gfs2/quota.c:1351
 gfs2_sync_fs+0x4c/0xb0 fs/gfs2/super.c:658
 sync_filesystem+0xee/0x230 fs/sync.c:56
 generic_shutdown_super+0x6f/0x2c0 fs/super.c:622
 kill_block_super+0x44/0x90 fs/super.c:1722
 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 ffff8880691fc000
 which belongs to the cache gfs2_quotad of size 272
The buggy address is located 120 bytes inside of
 freed 272-byte region [ffff8880691fc000, ffff8880691fc110)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880691fc000 pfn:0x691fc
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff8881426abc80 dead000000000122 0000000000000000
raw: ffff8880691fc000 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 12340, tgid 12335 (syz.9.1814), ts 736531874829, free_ts 717687204952
 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+0x24dc/0x2580 mm/page_alloc.c:3945
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240
 alloc_pages_mpol+0x232/0x4a0 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+0xd82/0x1760 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+0x3fe/0x6e0 mm/slub.c:5270
 qd_alloc+0x50/0x250 fs/gfs2/quota.c:234
 gfs2_quota_init+0x786/0x1220 fs/gfs2/quota.c:1448
 gfs2_make_fs_rw+0x143/0x220 fs/gfs2/super.c:149
 gfs2_fill_super+0x1b9a/0x21d0 fs/gfs2/ops_fstype.c:1275
 get_tree_bdev_flags+0x431/0x4f0 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+0x329/0xa50 fs/namespace.c:3712
page last free pid 12160 tgid 12160 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xbf8/0xd70 mm/page_alloc.c:2973
 discard_slab mm/slub.c:3346 [inline]
 __put_partials+0x146/0x170 mm/slub.c:3886
 __slab_free+0x294/0x320 mm/slub.c:5956
 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]
 kmem_cache_alloc_noprof+0x370/0x6e0 mm/slub.c:5270
 new_handle fs/jbd2/transaction.c:457 [inline]
 jbd2__journal_start+0x145/0x5b0 fs/jbd2/transaction.c:484
 __ext4_journal_start_sb+0x203/0x570 fs/ext4/ext4_jbd2.c:114
 __ext4_journal_start fs/ext4/ext4_jbd2.h:242 [inline]
 ext4_dirty_inode+0x93/0x110 fs/ext4/inode.c:6499
 __mark_inode_dirty+0x390/0x1320 fs/fs-writeback.c:2595
 generic_update_time fs/inode.c:2158 [inline]
 inode_update_time fs/inode.c:2171 [inline]
 file_update_time_flags+0x42d/0x4d0 fs/inode.c:2398
 ext4_page_mkwrite+0x219/0x11a0 fs/ext4/inode.c:6668
 do_page_mkwrite+0x14d/0x310 mm/memory.c:3531
 do_shared_fault mm/memory.c:5834 [inline]
 do_fault mm/memory.c:5896 [inline]
 do_pte_missing+0x67b/0x37a0 mm/memory.c:4404
 handle_pte_fault mm/memory.c:6276 [inline]
 __handle_mm_fault mm/memory.c:6414 [inline]
 handle_mm_fault+0x1b8c/0x32a0 mm/memory.c:6583

Memory state around the buggy address:
 ffff8880691fbf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880691fbf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880691fc000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff8880691fc080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880691fc100: fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================