ext4 filesystem being mounted at /1/file0 supports timestamps until 2038-01-19 (0x7fffffff) EXT4-fs warning (device loop2): dx_probe:833: inode #2: comm syz.2.18: Unrecognised inode hash code 20 EXT4-fs warning (device loop2): dx_probe:966: inode #2: comm syz.2.18: Corrupt directory, running e2fsck is recommended ================================================================== BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x7c2/0x970 fs/ext4/dir.c:85 Read of size 2 at addr ffff888110827003 by task syz.2.18/376 CPU: 0 PID: 376 Comm: syz.2.18 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:88 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:427 [inline] kasan_report+0xf1/0x140 mm/kasan/report.c:444 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report_generic.c:307 __ext4_check_dir_entry+0x7c2/0x970 fs/ext4/dir.c:85 ext4_readdir+0x123c/0x3b20 fs/ext4/dir.c:261 iterate_dir+0x260/0x600 fs/readdir.c:-1 __do_sys_getdents64 fs/readdir.c:369 [inline] __se_sys_getdents64+0xf2/0x250 fs/readdir.c:354 __x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354 x64_sys_call+0x592/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:218 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f858e10feb9 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:00007ffeeb526e18 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 00007f858e38afa0 RCX: 00007f858e10feb9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 00007f858e17dc1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f858e38afac R14: 00007f858e38afa0 R15: 00007f858e38afa0 Allocated by task 8: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:433 [inline] __kasan_slab_alloc+0xbd/0xf0 mm/kasan/common.c:466 kasan_slab_alloc include/linux/kasan.h:217 [inline] slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:550 slab_alloc_node mm/slub.c:3245 [inline] slab_alloc mm/slub.c:3255 [inline] kmem_cache_alloc+0xf7/0x260 mm/slub.c:3260 kmem_cache_alloc_node include/linux/slab.h:492 [inline] __alloc_skb+0xe0/0x740 net/core/skbuff.c:416 alloc_skb include/linux/skbuff.h:1183 [inline] nlmsg_new include/net/netlink.h:953 [inline] __neigh_notify+0x84/0x130 net/core/neighbour.c:3379 neigh_cleanup_and_release+0x2c/0x1a0 net/core/neighbour.c:101 neigh_flush_dev+0x6af/0x840 net/core/neighbour.c:374 __neigh_ifdown+0x3f/0x3a0 net/core/neighbour.c:391 neigh_ifdown+0x1f/0x30 net/core/neighbour.c:408 rt6_disable_ip+0x68a/0x710 net/ipv6/route.c:4914 addrconf_ifdown+0x150/0x18d0 net/ipv6/addrconf.c:3799 addrconf_notify+0x3bd/0xde0 net/ipv6/addrconf.c:-1 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2057 [inline] call_netdevice_notifiers_extack net/core/dev.c:2069 [inline] call_netdevice_notifiers net/core/dev.c:2083 [inline] dev_close_many+0x32e/0x4d0 net/core/dev.c:1658 unregister_netdevice_many+0x45e/0x1aa0 net/core/dev.c:11126 default_device_exit_batch+0x35e/0x3c0 net/core/dev.c:11683 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x60a/0xae0 net/core/net_namespace.c:599 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Freed by task 8: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4a/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:365 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373 kasan_slab_free include/linux/kasan.h:193 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1754 slab_free mm/slub.c:3526 [inline] kmem_cache_free+0x100/0x320 mm/slub.c:3544 kfree_skbmem+0x10c/0x180 net/core/skbuff.c:-1 __kfree_skb net/core/skbuff.c:758 [inline] consume_skb+0xb3/0x1f0 net/core/skbuff.c:930 netlink_broadcast_filtered+0x113a/0x1230 net/netlink/af_netlink.c:1538 netlink_broadcast net/netlink/af_netlink.c:1560 [inline] nlmsg_multicast include/net/netlink.h:1033 [inline] nlmsg_notify+0xed/0x1b0 net/netlink/af_netlink.c:2554 rtnl_notify+0x9a/0xc0 net/core/rtnetlink.c:759 __neigh_notify+0xd3/0x130 net/core/neighbour.c:3390 neigh_cleanup_and_release+0x2c/0x1a0 net/core/neighbour.c:101 neigh_flush_dev+0x6af/0x840 net/core/neighbour.c:374 __neigh_ifdown+0x3f/0x3a0 net/core/neighbour.c:391 neigh_ifdown+0x1f/0x30 net/core/neighbour.c:408 rt6_disable_ip+0x68a/0x710 net/ipv6/route.c:4914 addrconf_ifdown+0x150/0x18d0 net/ipv6/addrconf.c:3799 addrconf_notify+0x3bd/0xde0 net/ipv6/addrconf.c:-1 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2057 [inline] call_netdevice_notifiers_extack net/core/dev.c:2069 [inline] call_netdevice_notifiers net/core/dev.c:2083 [inline] dev_close_many+0x32e/0x4d0 net/core/dev.c:1658 unregister_netdevice_many+0x45e/0x1aa0 net/core/dev.c:11126 default_device_exit_batch+0x35e/0x3c0 net/core/dev.c:11683 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x60a/0xae0 net/core/net_namespace.c:599 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 The buggy address belongs to the object at ffff888110827000 which belongs to the cache skbuff_head_cache of size 248 The buggy address is located 3 bytes inside of 248-byte region [ffff888110827000, ffff8881108270f8) The buggy address belongs to the page: page:ffffea00044209c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x110827 flags: 0x4000000000000200(slab|zone=1) raw: 4000000000000200 dead000000000100 dead000000000122 ffff8881081aa000 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 101, ts 4898818672, free_ts 0 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605 prep_new_page+0x1c/0x110 mm/page_alloc.c:2611 get_page_from_freelist+0x2d3a/0x2dc0 mm/page_alloc.c:4485 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5808 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1937 [inline] new_slab+0xa1/0x4d0 mm/slub.c:2000 ___slab_alloc+0x381/0x810 mm/slub.c:3033 __slab_alloc+0x49/0x90 mm/slub.c:3120 slab_alloc_node mm/slub.c:3211 [inline] slab_alloc mm/slub.c:3255 [inline] kmem_cache_alloc+0x138/0x260 mm/slub.c:3260 kmem_cache_alloc_node include/linux/slab.h:492 [inline] __alloc_skb+0xe0/0x740 net/core/skbuff.c:416 alloc_skb include/linux/skbuff.h:1183 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1186 [inline] netlink_sendmsg+0x611/0xb80 net/netlink/af_netlink.c:1897 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] ____sys_sendmsg+0x5b7/0x8f0 net/socket.c:2435 ___sys_sendmsg+0x236/0x2e0 net/socket.c:2489 __sys_sendmsg net/socket.c:2518 [inline] __do_sys_sendmsg net/socket.c:2527 [inline] __se_sys_sendmsg net/socket.c:2525 [inline] __x64_sys_sendmsg+0x206/0x2f0 net/socket.c:2525 x64_sys_call+0x4b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 page_owner free stack trace missing Memory state around the buggy address: ffff888110826f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888110826f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888110827000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888110827080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc ffff888110827100: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ================================================================== EXT4-fs error (device loop2): ext4_readdir:263: inode #2: block 3: comm syz.2.18: path /1/file0: bad entry in directory: directory entry overrun - offset=2047, inode=3201564672, rec_len=33040, size=2048 fake=0 EXT4-fs error (device loop2) in ext4_reserve_inode_write:5885: Corrupt filesystem EXT4-fs error (device loop2): ext4_dirty_inode:6089: inode #2: comm syz.2.18: mark_inode_dirty error