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BUG: KASAN: use-after-free in ext4_htree_fill_tree+0x131b/0x13e0 fs/ext4/namei.c:1246
Read of size 1 at addr ffff88810e947a67 by task syz-executor/488

CPU: 0 PID: 488 Comm: syz-executor Not tainted 5.15.180-syzkaller-1080019-g8034ec1338e8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x151/0x1c0 lib/dump_stack.c:106
 print_address_description+0x87/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0x179/0x1c0 mm/kasan/report.c:444
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:306
 ext4_htree_fill_tree+0x131b/0x13e0 fs/ext4/namei.c:1246
 ext4_dx_readdir fs/ext4/dir.c:609 [inline]
 ext4_readdir+0x2f75/0x3960 fs/ext4/dir.c:145
 iterate_dir+0x265/0x600 fs/readdir.c:-1
 __do_sys_getdents64 fs/readdir.c:369 [inline]
 __se_sys_getdents64+0x1c1/0x460 fs/readdir.c:354
 __x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354
 x64_sys_call+0x5ae/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:218
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe020a9c693
Code: c1 66 0f 1f 44 00 00 48 83 c4 08 48 89 ef 5b 5d e9 82 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:00007fffcc1a0df8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00005555729484e0 RCX: 00007fe020a9c693
RDX: 0000000000008000 RSI: 00005555729484e0 RDI: 0000000000000005
RBP: 00005555729484b4 R08: 0000000000028b61 R09: 0000000000000000
R10: 00007fe020c2fca0 R11: 0000000000000293 R12: ffffffffffffffa8
R13: 0000000000000010 R14: 00005555729484b0 R15: 0000000000000001
 </TASK>

The buggy address belongs to the page:
page:ffffea00043a51c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10e947
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea00046702c8 ffffea00043d0788 0000000000000000
raw: 0000000000000000 00000000002a0000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 200, ts 11785077900, free_ts 57115213157
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1a3/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1b/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x3550/0x35d0 mm/page_alloc.c:4485
 __alloc_pages+0x27e/0x8f0 mm/page_alloc.c:5781
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1932 [inline]
 new_slab+0x9a/0x4e0 mm/slub.c:1995
 ___slab_alloc+0x39e/0x830 mm/slub.c:3028
 __slab_alloc+0x4a/0x90 mm/slub.c:3115
 slab_alloc_node mm/slub.c:3206 [inline]
 slab_alloc mm/slub.c:3250 [inline]
 kmem_cache_alloc+0x139/0x250 mm/slub.c:3255
 anon_vma_chain_alloc mm/rmap.c:141 [inline]
 anon_vma_fork+0x1df/0x4e0 mm/rmap.c:363
 dup_mmap kernel/fork.c:619 [inline]
 dup_mm kernel/fork.c:1522 [inline]
 copy_mm+0xa3a/0x13e0 kernel/fork.c:1574
 copy_process+0x1149/0x3290 kernel/fork.c:2263
 kernel_clone+0x21e/0x9e0 kernel/fork.c:2661
 __do_sys_clone kernel/fork.c:2787 [inline]
 __se_sys_clone kernel/fork.c:2771 [inline]
 __x64_sys_clone+0x23f/0x290 kernel/fork.c:2771
 x64_sys_call+0x1b0/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:57
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1472 [inline]
 free_pcp_prepare mm/page_alloc.c:1544 [inline]
 free_unref_page_prepare+0x7c8/0x7d0 mm/page_alloc.c:3534
 free_unref_page+0xe8/0x750 mm/page_alloc.c:3616
 free_the_page mm/page_alloc.c:805 [inline]
 __free_pages+0x61/0xf0 mm/page_alloc.c:5857
 __free_slab+0xec/0x1d0 mm/slub.c:2020
 free_slab mm/slub.c:2035 [inline]
 discard_slab+0x29/0x40 mm/slub.c:2041
 __slab_free+0x205/0x290 mm/slub.c:3426
 do_slab_free mm/slub.c:3509 [inline]
 ___cache_free+0x109/0x120 mm/slub.c:3530
 qlink_free+0x4d/0x90 mm/kasan/quarantine.c:157
 qlist_free_all+0x44/0xb0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x15a/0x180 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:443
 kasan_slab_alloc include/linux/kasan.h:217 [inline]
 slab_post_alloc_hook+0x53/0x2c0 mm/slab.h:550
 slab_alloc_node mm/slub.c:3240 [inline]
 slab_alloc mm/slub.c:3250 [inline]
 kmem_cache_alloc+0xf5/0x250 mm/slub.c:3255
 kmem_cache_alloc_node include/linux/slab.h:489 [inline]
 __alloc_skb+0xbe/0x550 net/core/skbuff.c:416
 alloc_skb include/linux/skbuff.h:1183 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1187 [inline]
 netlink_sendmsg+0x797/0xd20 net/netlink/af_netlink.c:1884
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2436

Memory state around the buggy address:
 ffff88810e947900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88810e947980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88810e947a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                                       ^
 ffff88810e947a80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88810e947b00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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