==================================================================
BUG: KASAN: use-after-free in ext4_search_dir+0xf7/0x1b0 fs/ext4/namei.c:1516
Read of size 1 at addr ffff888119c5e900 by task syz.6.16/518

CPU: 0 PID: 518 Comm: syz.6.16 Not tainted 5.10.226-syzkaller-1003449-g6a01908517df #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x81/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0x179/0x1c0 mm/kasan/report.c:452
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:306
 ext4_search_dir+0xf7/0x1b0 fs/ext4/namei.c:1516
 ext4_find_inline_entry+0x4b6/0x5e0 fs/ext4/inline.c:1700
 __ext4_find_entry+0x2b0/0x1990 fs/ext4/namei.c:1589
 ext4_lookup_entry fs/ext4/namei.c:1744 [inline]
 ext4_lookup+0x3c6/0xaa0 fs/ext4/namei.c:1812
 __lookup_hash+0x143/0x290 fs/namei.c:1541
 filename_create+0x202/0x750 fs/namei.c:3608
 user_path_create fs/namei.c:3665 [inline]
 do_mknodat+0x187/0x450 fs/namei.c:3729
 __do_sys_mknod fs/namei.c:3768 [inline]
 __se_sys_mknod fs/namei.c:3766 [inline]
 __x64_sys_mknod+0x80/0x90 fs/namei.c:3766
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f912296c719
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f91223ed038 EFLAGS: 00000246 ORIG_RAX: 0000000000000085
RAX: ffffffffffffffda RBX: 00007f9122b23f80 RCX: 00007f912296c719
RDX: 000000000000070d RSI: 0000000000000000 RDI: 0000000020000000
RBP: 00007f91229df32e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f9122b23f80 R15: 00007fff826e73d8

Allocated by task 501:
 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:430 [inline]
 __kasan_slab_alloc+0xb1/0xe0 mm/kasan/common.c:463
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x61/0x2f0 mm/slab.h:583
 slab_alloc_node mm/slub.c:2947 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 kmem_cache_alloc+0x168/0x2e0 mm/slub.c:2960
 kmem_cache_alloc_node include/linux/slab.h:423 [inline]
 __alloc_skb+0x80/0x510 net/core/skbuff.c:200
 alloc_skb include/linux/skbuff.h:1126 [inline]
 nlmsg_new include/net/netlink.h:953 [inline]
 inet6_rt_notify+0x2db/0x550 net/ipv6/route.c:6047
 fib6_add_rt2node net/ipv6/ip6_fib.c:1253 [inline]
 fib6_add+0x233e/0x3d20 net/ipv6/ip6_fib.c:1482
 __ip6_ins_rt net/ipv6/route.c:1303 [inline]
 ip6_route_add+0x8a/0x130 net/ipv6/route.c:3765
 addrconf_prefix_route net/ipv6/addrconf.c:2461 [inline]
 fixup_permanent_addr net/ipv6/addrconf.c:3515 [inline]
 addrconf_permanent_addr+0x757/0xba0 net/ipv6/addrconf.c:3539
 addrconf_notify+0x75b/0xe90 net/ipv6/addrconf.c:3607
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x8c/0xf0 kernel/notifier.c:410
 __dev_notify_flags+0x304/0x610
 dev_change_flags+0xf0/0x1a0 net/core/dev.c:8590
 do_setlink+0xc5c/0x3c30 net/core/rtnetlink.c:2729
 __rtnl_newlink net/core/rtnetlink.c:3407 [inline]
 rtnl_newlink+0x15f0/0x2000 net/core/rtnetlink.c:3527
 rtnetlink_rcv_msg+0x955/0xc50 net/core/rtnetlink.c:5607
 netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2499
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5625
 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]
 netlink_unicast+0x8df/0xac0 net/netlink/af_netlink.c:1348
 netlink_sendmsg+0xa46/0xd00 net/netlink/af_netlink.c:1916
 sock_sendmsg_nosec net/socket.c:652 [inline]
 __sock_sendmsg net/socket.c:664 [inline]
 __sys_sendto+0x545/0x700 net/socket.c:2006
 __do_sys_sendto net/socket.c:2018 [inline]
 __se_sys_sendto net/socket.c:2014 [inline]
 __x64_sys_sendto+0xe5/0x100 net/socket.c:2014
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Freed by task 501:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x121/0x160 mm/kasan/common.c:362
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
 kasan_slab_free include/linux/kasan.h:220 [inline]
 slab_free_hook mm/slub.c:1595 [inline]
 slab_free_freelist_hook+0xc0/0x190 mm/slub.c:1621
 slab_free mm/slub.c:3203 [inline]
 kmem_cache_free+0xa9/0x1e0 mm/slub.c:3219
 kfree_skbmem+0x104/0x170
 __kfree_skb net/core/skbuff.c:695 [inline]
 consume_skb+0xb4/0x250 net/core/skbuff.c:851
 netlink_broadcast_filtered+0x114e/0x1270 net/netlink/af_netlink.c:1532
 netlink_broadcast net/netlink/af_netlink.c:1554 [inline]
 nlmsg_multicast include/net/netlink.h:1033 [inline]
 nlmsg_notify+0x101/0x1c0 net/netlink/af_netlink.c:2542
 rtnl_notify+0x9c/0xd0 net/core/rtnetlink.c:737
 inet6_rt_notify+0x3c8/0x550 net/ipv6/route.c:6059
 fib6_add_rt2node net/ipv6/ip6_fib.c:1253 [inline]
 fib6_add+0x233e/0x3d20 net/ipv6/ip6_fib.c:1482
 __ip6_ins_rt net/ipv6/route.c:1303 [inline]
 ip6_route_add+0x8a/0x130 net/ipv6/route.c:3765
 addrconf_prefix_route net/ipv6/addrconf.c:2461 [inline]
 fixup_permanent_addr net/ipv6/addrconf.c:3515 [inline]
 addrconf_permanent_addr+0x757/0xba0 net/ipv6/addrconf.c:3539
 addrconf_notify+0x75b/0xe90 net/ipv6/addrconf.c:3607
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0x8c/0xf0 kernel/notifier.c:410
 __dev_notify_flags+0x304/0x610
 dev_change_flags+0xf0/0x1a0 net/core/dev.c:8590
 do_setlink+0xc5c/0x3c30 net/core/rtnetlink.c:2729
 __rtnl_newlink net/core/rtnetlink.c:3407 [inline]
 rtnl_newlink+0x15f0/0x2000 net/core/rtnetlink.c:3527
 rtnetlink_rcv_msg+0x955/0xc50 net/core/rtnetlink.c:5607
 netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2499
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:5625
 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]
 netlink_unicast+0x8df/0xac0 net/netlink/af_netlink.c:1348
 netlink_sendmsg+0xa46/0xd00 net/netlink/af_netlink.c:1916
 sock_sendmsg_nosec net/socket.c:652 [inline]
 __sock_sendmsg net/socket.c:664 [inline]
 __sys_sendto+0x545/0x700 net/socket.c:2006
 __do_sys_sendto net/socket.c:2018 [inline]
 __se_sys_sendto net/socket.c:2014 [inline]
 __x64_sys_sendto+0xe5/0x100 net/socket.c:2014
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

The buggy address belongs to the object at ffff888119c5e8c0
 which belongs to the cache skbuff_head_cache of size 248
The buggy address is located 64 bytes inside of
 248-byte region [ffff888119c5e8c0, ffff888119c5e9b8)
The buggy address belongs to the page:
page:ffffea0004671780 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x119c5e
flags: 0x4000000000000200(slab)
raw: 4000000000000200 dead000000000100 dead000000000122 ffff888107d9d080
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 0x112a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 501, ts 54703721953, free_ts 54693080149
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x166/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5348
 allocate_slab mm/slub.c:1808 [inline]
 new_slab+0x80/0x400 mm/slub.c:1869
 new_slab_objects mm/slub.c:2627 [inline]
 ___slab_alloc+0x302/0x4b0 mm/slub.c:2791
 __slab_alloc+0x63/0xa0 mm/slub.c:2831
 slab_alloc_node mm/slub.c:2913 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 kmem_cache_alloc+0x1b9/0x2e0 mm/slub.c:2960
 kmem_cache_alloc_node include/linux/slab.h:423 [inline]
 __alloc_skb+0x80/0x510 net/core/skbuff.c:200
 alloc_skb include/linux/skbuff.h:1126 [inline]
 nlmsg_new include/net/netlink.h:953 [inline]
 rtmsg_ifinfo_build_skb+0x7f/0x180 net/core/rtnetlink.c:3841
 rtmsg_ifinfo_event net/core/rtnetlink.c:3877 [inline]
 rtmsg_ifinfo+0x78/0x120 net/core/rtnetlink.c:3886
 __dev_notify_flags+0xdd/0x610 net/core/dev.c:8548
 dev_change_flags+0xf0/0x1a0 net/core/dev.c:8590
 do_setlink+0xc5c/0x3c30 net/core/rtnetlink.c:2729
 __rtnl_newlink net/core/rtnetlink.c:3407 [inline]
 rtnl_newlink+0x15f0/0x2000 net/core/rtnetlink.c:3527
 rtnetlink_rcv_msg+0x955/0xc50 net/core/rtnetlink.c:5607
 netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2499
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 free_pcp_prepare mm/page_alloc.c:1421 [inline]
 free_unref_page_prepare+0x2ae/0x2d0 mm/page_alloc.c:3336
 free_unref_page mm/page_alloc.c:3391 [inline]
 free_the_page+0x9e/0x370 mm/page_alloc.c:5407
 __free_pages+0x67/0xc0 mm/page_alloc.c:5418
 __free_slab+0xcf/0x190 mm/slub.c:1894
 free_slab mm/slub.c:1909 [inline]
 discard_slab mm/slub.c:1915 [inline]
 unfreeze_partials+0x15e/0x190 mm/slub.c:2410
 put_cpu_partial+0xbf/0x180 mm/slub.c:2446
 __slab_free+0x2c8/0x3a0 mm/slub.c:3095
 do_slab_free mm/slub.c:3191 [inline]
 ___cache_free+0x111/0x130 mm/slub.c:3210
 qlink_free+0x50/0x90 mm/kasan/quarantine.c:157
 qlist_free_all+0x47/0xb0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x15a/0x170 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:440
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x61/0x2f0 mm/slab.h:583
 slab_alloc_node mm/slub.c:2947 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 __kmalloc+0x183/0x330 mm/slub.c:4029
 __kmalloc_node include/linux/slab.h:418 [inline]
 kmalloc_node include/linux/slab.h:575 [inline]
 kvmalloc_node+0x82/0x130 mm/util.c:612
 kvmalloc include/linux/mm.h:822 [inline]
 seq_buf_alloc fs/seq_file.c:38 [inline]
 seq_read_iter+0x1ff/0xd00 fs/seq_file.c:210

Memory state around the buggy address:
 ffff888119c5e800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc
 ffff888119c5e880: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>ffff888119c5e900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888119c5e980: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc
 ffff888119c5ea00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
EXT4-fs error (device loop6): ext4_find_dest_de:2077: inode #12: block 7: comm syz.6.16: bad entry in directory: directory entry overrun - offset=0, inode=1793120026, rec_len=34652, size=56 fake=0