================================================================== BUG: KASAN: use-after-free in ext4_htree_fill_tree+0x1066/0x10d0 fs/ext4/namei.c:1246 Read of size 1 at addr ffff888134d4e365 by task syz-executor/3280 CPU: 0 PID: 3280 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: __dump_stack+0x21/0x24 lib/dump_stack.c:88 dump_stack_lvl+0xee/0x150 lib/dump_stack.c:106 print_address_description+0x71/0x200 mm/kasan/report.c:316 print_report+0x4a/0x60 mm/kasan/report.c:420 kasan_report+0x122/0x150 mm/kasan/report.c:524 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:348 ext4_htree_fill_tree+0x1066/0x10d0 fs/ext4/namei.c:1246 ext4_dx_readdir fs/ext4/dir.c:608 [inline] ext4_readdir+0x2d8a/0x3c10 fs/ext4/dir.c:145 iterate_dir+0x271/0x610 fs/readdir.c:-1 __do_sys_getdents64 fs/readdir.c:369 [inline] __se_sys_getdents64+0xe5/0x240 fs/readdir.c:354 __x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354 x64_sys_call+0x15c/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:218 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fd3ed9bf753 Code: c1 66 0f 1f 44 00 00 48 83 c4 08 48 89 ef 5b 5d e9 52 3e f8 ff 66 90 b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 c7 c2 a8 ff ff ff f7 d8 RSP: 002b:00007ffecba52ae8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 0000555582bc94e0 RCX: 00007fd3ed9bf753 RDX: 0000000000008000 RSI: 0000555582bc94e0 RDI: 0000000000000005 RBP: 0000555582bc94b4 R08: 0000000000028b61 R09: 0000000000000000 R10: 00007fd3edb7cca0 R11: 0000000000000293 R12: ffffffffffffffa8 R13: 0000000000000010 R14: 0000555582bc94b0 R15: 00007ffecba54da0 Allocated by task 3295: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_alloc_info+0x25/0x30 mm/kasan/generic.c:505 __kasan_slab_alloc+0x72/0x80 mm/kasan/common.c:333 kasan_slab_alloc include/linux/kasan.h:202 [inline] slab_post_alloc_hook+0x4f/0x2d0 mm/slab.h:768 slab_alloc_node mm/slub.c:3382 [inline] kmem_cache_alloc_node+0x181/0x340 mm/slub.c:3429 __alloc_skb+0xea/0x4b0 net/core/skbuff.c:508 alloc_skb include/linux/skbuff.h:1290 [inline] nlmsg_new include/net/netlink.h:991 [inline] rtmsg_fib+0x60a/0xe20 net/ipv4/fib_semantics.c:522 fib_table_insert+0xf37/0x1d00 net/ipv4/fib_trie.c:1385 fib_magic net/ipv4/fib_frontend.c:1118 [inline] fib_add_ifaddr+0x7f8/0xd20 net/ipv4/fib_frontend.c:1155 fib_netdev_event+0x231/0x5b0 net/ipv4/fib_frontend.c:1500 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0xa1/0x110 kernel/notifier.c:455 call_netdevice_notifiers_info net/core/dev.c:2009 [inline] call_netdevice_notifiers_extack net/core/dev.c:2047 [inline] call_netdevice_notifiers net/core/dev.c:2061 [inline] __dev_notify_flags+0x28f/0x500 net/core/dev.c:-1 dev_change_flags+0xe8/0x1a0 net/core/dev.c:8730 do_setlink+0xc3d/0x3d50 net/core/rtnetlink.c:2833 __rtnl_newlink net/core/rtnetlink.c:3608 [inline] rtnl_newlink+0x17d9/0x2030 net/core/rtnetlink.c:3655 rtnetlink_rcv_msg+0x9f4/0xcf0 net/core/rtnetlink.c:6153 netlink_rcv_skb+0x1f2/0x440 net/netlink/af_netlink.c:2521 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6171 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x8ab/0xa30 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x8aa/0xbc0 net/netlink/af_netlink.c:1873 sock_sendmsg_nosec net/socket.c:716 [inline] __sock_sendmsg net/socket.c:728 [inline] __sys_sendto+0x464/0x5e0 net/socket.c:2143 __do_sys_sendto net/socket.c:2155 [inline] __se_sys_sendto net/socket.c:2151 [inline] __x64_sys_sendto+0xe5/0x100 net/socket.c:2151 x64_sys_call+0x83/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:45 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 3295: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x31/0x50 mm/kasan/generic.c:516 ____kasan_slab_free+0x132/0x180 mm/kasan/common.c:241 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:249 kasan_slab_free include/linux/kasan.h:178 [inline] slab_free_hook mm/slub.c:1750 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776 slab_free mm/slub.c:3712 [inline] kmem_cache_free+0x12d/0x300 mm/slub.c:3737 kfree_skbmem+0x10c/0x180 net/core/skbuff.c:-1 __kfree_skb net/core/skbuff.c:874 [inline] consume_skb+0xb3/0x1f0 net/core/skbuff.c:1038 netlink_broadcast+0x1084/0x1180 net/netlink/af_netlink.c:1522 nlmsg_multicast include/net/netlink.h:1071 [inline] nlmsg_notify+0xe6/0x1a0 net/netlink/af_netlink.c:2564 rtnl_notify+0x9a/0xc0 net/core/rtnetlink.c:796 rtmsg_fib+0x7d5/0xe20 net/ipv4/fib_semantics.c:542 fib_table_insert+0xf37/0x1d00 net/ipv4/fib_trie.c:1385 fib_magic net/ipv4/fib_frontend.c:1118 [inline] fib_add_ifaddr+0x7f8/0xd20 net/ipv4/fib_frontend.c:1155 fib_netdev_event+0x231/0x5b0 net/ipv4/fib_frontend.c:1500 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0xa1/0x110 kernel/notifier.c:455 call_netdevice_notifiers_info net/core/dev.c:2009 [inline] call_netdevice_notifiers_extack net/core/dev.c:2047 [inline] call_netdevice_notifiers net/core/dev.c:2061 [inline] __dev_notify_flags+0x28f/0x500 net/core/dev.c:-1 dev_change_flags+0xe8/0x1a0 net/core/dev.c:8730 do_setlink+0xc3d/0x3d50 net/core/rtnetlink.c:2833 __rtnl_newlink net/core/rtnetlink.c:3608 [inline] rtnl_newlink+0x17d9/0x2030 net/core/rtnetlink.c:3655 rtnetlink_rcv_msg+0x9f4/0xcf0 net/core/rtnetlink.c:6153 netlink_rcv_skb+0x1f2/0x440 net/netlink/af_netlink.c:2521 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6171 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x8ab/0xa30 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x8aa/0xbc0 net/netlink/af_netlink.c:1873 sock_sendmsg_nosec net/socket.c:716 [inline] __sock_sendmsg net/socket.c:728 [inline] __sys_sendto+0x464/0x5e0 net/socket.c:2143 __do_sys_sendto net/socket.c:2155 [inline] __se_sys_sendto net/socket.c:2151 [inline] __x64_sys_sendto+0xe5/0x100 net/socket.c:2151 x64_sys_call+0x83/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:45 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff888134d4e280 which belongs to the cache skbuff_head_cache of size 256 The buggy address is located 229 bytes inside of 256-byte region [ffff888134d4e280, ffff888134d4e380) The buggy address belongs to the physical page: page:ffffea0004d35380 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x134d4e flags: 0x4000000000000200(slab|zone=1) raw: 4000000000000200 0000000000000000 dead000000000122 ffff888108856300 raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 3295, tgid 3295 (syz-executor), ts 222225646383, free_ts 222072830564 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2643 prep_new_page+0x1c/0x110 mm/page_alloc.c:2650 get_page_from_freelist+0x2c7b/0x2cf0 mm/page_alloc.c:4554 __alloc_pages+0x1c3/0x450 mm/page_alloc.c:5868 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1 allocate_slab mm/slub.c:1967 [inline] new_slab+0x98/0x3d0 mm/slub.c:2020 ___slab_alloc+0x6bd/0xb20 mm/slub.c:3177 __slab_alloc+0x5e/0xa0 mm/slub.c:3263 slab_alloc_node mm/slub.c:3348 [inline] kmem_cache_alloc_node+0x1c2/0x340 mm/slub.c:3429 __alloc_skb+0xea/0x4b0 net/core/skbuff.c:508 alloc_skb include/linux/skbuff.h:1290 [inline] nlmsg_new include/net/netlink.h:991 [inline] rtmsg_ifa+0xfa/0x1e0 net/ipv4/devinet.c:1933 __inet_insert_ifa+0x834/0xa10 net/ipv4/devinet.c:567 inet_rtm_newaddr+0xcd1/0x1600 net/ipv4/devinet.c:970 rtnetlink_rcv_msg+0x9f4/0xcf0 net/core/rtnetlink.c:6153 netlink_rcv_skb+0x1f2/0x440 net/netlink/af_netlink.c:2521 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6171 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1551 [inline] free_pcp_prepare mm/page_alloc.c:1625 [inline] free_unref_page_prepare+0x742/0x750 mm/page_alloc.c:3589 free_unref_page+0x8f/0x530 mm/page_alloc.c:3687 free_the_page mm/page_alloc.c:836 [inline] __free_pages+0x67/0x100 mm/page_alloc.c:5957 __free_slab+0xca/0x1a0 mm/slub.c:2044 free_slab mm/slub.c:2059 [inline] discard_slab+0x29/0x40 mm/slub.c:2065 __slab_free+0x201/0x280 mm/slub.c:3625 do_slab_free mm/slub.c:3666 [inline] ___cache_free+0xbf/0xd0 mm/slub.c:3722 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0xc6/0x140 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x24/0x80 mm/kasan/common.c:310 kasan_slab_alloc include/linux/kasan.h:202 [inline] slab_post_alloc_hook+0x4f/0x2d0 mm/slab.h:768 slab_alloc_node mm/slub.c:3382 [inline] slab_alloc mm/slub.c:3392 [inline] __kmem_cache_alloc_lru mm/slub.c:3399 [inline] kmem_cache_alloc_lru+0x104/0x280 mm/slub.c:3415 alloc_inode_sb include/linux/fs.h:3263 [inline] sock_alloc_inode+0x28/0xc0 net/socket.c:304 alloc_inode fs/inode.c:264 [inline] new_inode_pseudo+0x70/0x1f0 fs/inode.c:1073 sock_alloc net/socket.c:629 [inline] __sock_create+0x12c/0x7c0 net/socket.c:1504 sock_create net/socket.c:1596 [inline] __sys_socket_create net/socket.c:1633 [inline] __sys_socket+0xcd/0x1a0 net/socket.c:1661 Memory state around the buggy address: ffff888134d4e200: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff888134d4e280: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888134d4e300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888134d4e380: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ffff888134d4e400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== EXT4-fs error (device loop5): htree_dirblock_to_tree:1112: inode #2: block 20: comm syz-executor: bad entry in directory: inode out of bounds - offset=1024, inode=2033530174, rec_len=1012, size=1024 fake=0 EXT4-fs error (device loop5): htree_dirblock_to_tree:1112: inode #2: block 20: comm syz-executor: bad entry in directory: inode out of bounds - offset=1024, inode=2033530174, rec_len=1012, size=1024 fake=0 EXT4-fs error (device loop5): htree_dirblock_to_tree:1112: inode #2: block 20: comm syz-executor: bad entry in directory: inode out of bounds - offset=1024, inode=2033530174, rec_len=1012, size=1024 fake=0 EXT4-fs error (device loop5): htree_dirblock_to_tree:1112: inode #2: block 20: comm syz-executor: bad entry in directory: inode out of bounds - offset=1024, inode=2033530174, rec_len=1012, size=1024 fake=0 EXT4-fs error (device loop5): htree_dirblock_to_tree:1112: inode #2: block 20: comm syz-executor: bad entry in directory: inode out of bounds - offset=1024, inode=2033530174, rec_len=1012, size=1024 fake=0 EXT4-fs error (device loop5): htree_dirblock_to_tree:1112: inode #2: block 20: comm syz-executor: bad entry in directory: inode out of bounds - offset=1024, inode=2033530174, rec_len=1012, size=1024 fake=0 EXT4-fs error (device loop5): htree_dirblock_to_tree:1112: inode #2: block 20: comm syz-executor: bad entry in directory: inode out of bounds - offset=1024, inode=2033530174, rec_len=1012, size=1024 fake=0 EXT4-fs (loop5): unmounting filesystem.