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BUG: KASAN: use-after-free in f2fs_available_free_memory+0xa98/0xb00 fs/f2fs/node.c:99
Read of size 4 at addr ffff88810b2d9010 by task f2fs_discard-7:/21553

CPU: 1 PID: 21553 Comm: f2fs_discard-7: Tainted: G        W         5.10.100-syzkaller-00843-g86e6176a4240 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x8d/0x3d0 mm/kasan/report.c:233
 __kasan_report+0x142/0x220 mm/kasan/report.c:419
 kasan_report+0x51/0x70 mm/kasan/report.c:436
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 f2fs_available_free_memory+0xa98/0xb00 fs/f2fs/node.c:99
 issue_discard_thread+0x2dd/0x1b00 fs/f2fs/segment.c:1761
 kthread+0x371/0x390 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Allocated by task 21537:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:428 [inline]
 ____kasan_kmalloc+0xdc/0x110 mm/kasan/common.c:507
 __kasan_kmalloc+0x9/0x10 mm/kasan/common.c:516
 kasan_kmalloc include/linux/kasan.h:269 [inline]
 kmem_cache_alloc_trace+0x210/0x3a0 mm/slub.c:2981
 kmalloc include/linux/slab.h:552 [inline]
 f2fs_kmalloc fs/f2fs/f2fs.h:3246 [inline]
 f2fs_kzalloc fs/f2fs/f2fs.h:3252 [inline]
 f2fs_build_node_manager+0x57/0x13b0 fs/f2fs/node.c:3217
 f2fs_fill_super+0x5f24/0x9260 fs/f2fs/super.c:4032
 mount_bdev+0x25f/0x370 fs/super.c:1419
 f2fs_mount+0x34/0x40 fs/f2fs/super.c:4302
 legacy_get_tree+0xf0/0x190 fs/fs_context.c:592
 vfs_get_tree+0x89/0x270 fs/super.c:1549
 do_new_mount fs/namespace.c:2899 [inline]
 path_mount+0x1975/0x2ab0 fs/namespace.c:3229
 do_mount fs/namespace.c:3242 [inline]
 __do_sys_mount fs/namespace.c:3450 [inline]
 __se_sys_mount+0x2f7/0x3b0 fs/namespace.c:3427
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3427
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 21537:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:46
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:357
 ____kasan_slab_free+0x133/0x170 mm/kasan/common.c:360
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:368
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:1602 [inline]
 slab_free_freelist_hook+0xcc/0x1a0 mm/slub.c:1628
 slab_free mm/slub.c:3210 [inline]
 kfree+0xd5/0x320 mm/slub.c:4198
 f2fs_destroy_node_manager+0xe1d/0xf80 fs/f2fs/node.c:3310
 f2fs_fill_super+0x729a/0x9260 fs/f2fs/super.c:4247
 mount_bdev+0x25f/0x370 fs/super.c:1419
 f2fs_mount+0x34/0x40 fs/f2fs/super.c:4302
 legacy_get_tree+0xf0/0x190 fs/fs_context.c:592
 vfs_get_tree+0x89/0x270 fs/super.c:1549
 do_new_mount fs/namespace.c:2899 [inline]
 path_mount+0x1975/0x2ab0 fs/namespace.c:3229
 do_mount fs/namespace.c:3242 [inline]
 __do_sys_mount fs/namespace.c:3450 [inline]
 __se_sys_mount+0x2f7/0x3b0 fs/namespace.c:3427
 __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3427
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88810b2d9000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 16 bytes inside of
 512-byte region [ffff88810b2d9000, ffff88810b2d9200)
The buggy address belongs to the page:
page:ffffea00042cb600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10b2d8
head:ffffea00042cb600 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 ffffea00055b0200 0000000200000002 ffff888100043080
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 2071769641, free_ts 2070180131
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2385 [inline]
 prep_new_page mm/page_alloc.c:2391 [inline]
 get_page_from_freelist+0xa74/0xa90 mm/page_alloc.c:4063
 __alloc_pages_nodemask+0x3c8/0x820 mm/page_alloc.c:5107
 alloc_slab_page mm/slub.c:1813 [inline]
 allocate_slab+0x6b/0x350 mm/slub.c:1815
 new_slab mm/slub.c:1876 [inline]
 new_slab_objects mm/slub.c:2635 [inline]
 ___slab_alloc+0x143/0x2f0 mm/slub.c:2798
 __slab_alloc mm/slub.c:2838 [inline]
 slab_alloc_node mm/slub.c:2920 [inline]
 slab_alloc mm/slub.c:2962 [inline]
 __kmalloc_track_caller+0x299/0x3b0 mm/slub.c:4543
 __kmalloc_reserve net/core/skbuff.c:143 [inline]
 __alloc_skb+0xb7/0x580 net/core/skbuff.c:211
 alloc_skb include/linux/skbuff.h:1101 [inline]
 alloc_uevent_skb+0x7f/0x230 lib/kobject_uevent.c:290
 uevent_net_broadcast_tagged lib/kobject_uevent.c:351 [inline]
 kobject_uevent_net_broadcast lib/kobject_uevent.c:412 [inline]
 kobject_uevent_env+0xbfb/0x1400 lib/kobject_uevent.c:593
 kobject_uevent+0x1f/0x30 lib/kobject_uevent.c:642
 device_add+0xfd4/0x1590 drivers/base/core.c:3221
 netdev_register_kobject+0x179/0x320 net/core/net-sysfs.c:1997
 register_netdevice+0x11b5/0x1ad0 net/core/dev.c:10114
 register_netdev+0x3c/0x50 net/core/dev.c:10245
 sit_init_net+0x243/0x480 net/ipv6/sit.c:1914
 ops_init+0x199/0x380 net/core/net_namespace.c:152
 __register_pernet_operations net/core/net_namespace.c:1162 [inline]
 register_pernet_operations+0x2de/0xa40 net/core/net_namespace.c:1239
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1331 [inline]
 __free_pages_ok+0xbe7/0xc20 mm/page_alloc.c:1611
 free_the_page mm/page_alloc.c:5168 [inline]
 __free_pages+0x2d6/0x4a0 mm/page_alloc.c:5174
 free_pages+0x7c/0x90 mm/page_alloc.c:5185
 stack_depot_save+0x431/0x480 lib/stackdepot.c:336
 kasan_save_stack mm/kasan/common.c:40 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:428 [inline]
 __kasan_slab_alloc+0xc9/0xe0 mm/kasan/common.c:461
 kasan_slab_alloc include/linux/kasan.h:259 [inline]
 slab_post_alloc_hook mm/slab.h:583 [inline]
 slab_alloc_node mm/slub.c:2954 [inline]
 slab_alloc mm/slub.c:2962 [inline]
 kmem_cache_alloc+0x1a2/0x380 mm/slub.c:2967
 kmem_cache_zalloc include/linux/slab.h:654 [inline]
 __kernfs_new_node+0xdb/0x6e0 fs/kernfs/dir.c:627
 kernfs_new_node+0x97/0x170 fs/kernfs/dir.c:689
 __kernfs_create_file+0x4a/0x270 fs/kernfs/file.c:985
 sysfs_add_file_mode_ns+0x274/0x320 fs/sysfs/file.c:306
 create_files fs/sysfs/group.c:64 [inline]
 internal_create_group+0x560/0xf10 fs/sysfs/group.c:149
 sysfs_create_group+0x1f/0x30 fs/sysfs/group.c:175
 netdev_queue_add_kobject net/core/net-sysfs.c:1655 [inline]
 netdev_queue_update_kobjects+0x199/0x3c0 net/core/net-sysfs.c:1694
 register_queue_kobjects net/core/net-sysfs.c:1755 [inline]
 netdev_register_kobject+0x270/0x320 net/core/net-sysfs.c:2001
 register_netdevice+0x11b5/0x1ad0 net/core/dev.c:10114
 register_netdev+0x3c/0x50 net/core/dev.c:10245

Memory state around the buggy address:
 ffff88810b2d8f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810b2d8f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88810b2d9000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88810b2d9080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88810b2d9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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