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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 ffff88815375d410 by task f2fs_discard-7:/14235

CPU: 0 PID: 14235 Comm: f2fs_discard-7: Tainted: G        W         5.10.87-syzkaller-00611-gc4d08791d941 #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 14224:
 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:2975
 kmalloc include/linux/slab.h:552 [inline]
 f2fs_kmalloc fs/f2fs/f2fs.h:3167 [inline]
 f2fs_kzalloc fs/f2fs/f2fs.h:3173 [inline]
 f2fs_build_node_manager+0x57/0x1390 fs/f2fs/node.c:3212
 f2fs_fill_super+0x6447/0x8f90 fs/f2fs/super.c:3992
 mount_bdev+0x25f/0x370 fs/super.c:1419
 f2fs_mount+0x34/0x40 fs/f2fs/super.c:4258
 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 14224:
 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:1596 [inline]
 slab_free_freelist_hook+0xcc/0x1a0 mm/slub.c:1622
 slab_free mm/slub.c:3204 [inline]
 kfree+0xd5/0x320 mm/slub.c:4192
 f2fs_destroy_node_manager+0xdfd/0xf60 fs/f2fs/node.c:3305
 f2fs_fill_super+0x7475/0x8f90 fs/f2fs/super.c:4203
 mount_bdev+0x25f/0x370 fs/super.c:1419
 f2fs_mount+0x34/0x40 fs/f2fs/super.c:4258
 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 ffff88815375d400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 16 bytes inside of
 512-byte region [ffff88815375d400, ffff88815375d600)
The buggy address belongs to the page:
page:ffffea00054dd700 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x15375c
head:ffffea00054dd700 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 0000000000000000 0000000b00000001 ffff888100043080
raw: 0000000000000000 0000000080100010 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 382, ts 118557283761, free_ts 0
 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:5106
 alloc_slab_page mm/slub.c:1807 [inline]
 allocate_slab+0x6b/0x350 mm/slub.c:1809
 new_slab mm/slub.c:1870 [inline]
 new_slab_objects mm/slub.c:2629 [inline]
 ___slab_alloc+0x143/0x2f0 mm/slub.c:2792
 __slab_alloc mm/slub.c:2832 [inline]
 slab_alloc_node mm/slub.c:2914 [inline]
 slab_alloc mm/slub.c:2956 [inline]
 __kmalloc+0x2af/0x3d0 mm/slub.c:4030
 kmalloc include/linux/slab.h:557 [inline]
 kzalloc include/linux/slab.h:664 [inline]
 fib6_info_alloc+0x33/0xe0 net/ipv6/ip6_fib.c:154
 ip6_route_info_create+0x588/0x1aa0 net/ipv6/route.c:3644
 ip6_route_add+0x27/0x130 net/ipv6/route.c:3738
 addrconf_prefix_route net/ipv6/addrconf.c:2436 [inline]
 inet6_addr_add+0x9e9/0x1140 net/ipv6/addrconf.c:2969
 inet6_rtm_newaddr+0x8f6/0x2a20 net/ipv6/addrconf.c:4898
 rtnetlink_rcv_msg+0xbae/0xd70 net/core/rtnetlink.c:5567
 netlink_rcv_skb+0x200/0x470 net/netlink/af_netlink.c:2507
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5585
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x814/0x9f0 net/netlink/af_netlink.c:1337
 netlink_sendmsg+0xb47/0xe60 net/netlink/af_netlink.c:1932
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 __sys_sendto+0x541/0x700 net/socket.c:1982
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88815375d300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88815375d380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88815375d400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88815375d480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88815375d500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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