==================================================================
BUG: KASAN: use-after-free in dtMoveEntry fs/jfs/jfs_dtree.c:3922 [inline]
BUG: KASAN: use-after-free in dtSplitPage+0x1e37/0x3b20 fs/jfs/jfs_dtree.c:1561
Write of size 1 at addr ffff88805e2d6000 by task syz.0.19/6524

CPU: 0 UID: 0 PID: 6524 Comm: syz.0.19 Not tainted 6.15.0-rc7-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x185/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xb0/0x290 mm/kasan/report.c:521
 kasan_report+0x114/0x150 mm/kasan/report.c:634
 dtMoveEntry fs/jfs/jfs_dtree.c:3922 [inline]
 dtSplitPage+0x1e37/0x3b20 fs/jfs/jfs_dtree.c:1561
 dtSplitUp fs/jfs/jfs_dtree.c:1092 [inline]
 dtInsert+0x1097/0x5f40 fs/jfs/jfs_dtree.c:871
 jfs_create+0x6c4/0xa80 fs/jfs/namei.c:137
 lookup_open fs/namei.c:3701 [inline]
 open_last_lookups fs/namei.c:3800 [inline]
 path_openat+0x14f0/0x3830 fs/namei.c:4036
 do_filp_open+0x1f6/0x400 fs/namei.c:4066
 do_sys_openat2+0x11d/0x1b0 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_sys_creat fs/open.c:1522 [inline]
 __se_sys_creat fs/open.c:1516 [inline]
 __x64_sys_creat+0x8b/0xb0 fs/open.c:1516
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x7b/0x150 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f7aa358e969
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:00007f7aa44a5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007f7aa37b6080 RCX: 00007f7aa358e969
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000006c0
RBP: 00007f7aa3610ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f7aa37b6080 R15: 00007ffe5896a318
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88805e2d6000 pfn:0x5e2d6
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001f0c808 ffff8880b883f7a0 0000000000000000
raw: ffff88805e2d6000 00000000000c0000 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 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 6261, tgid 6261 (syz-executor), ts 142069068908, free_ts 153420075420
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c8/0x220 mm/page_alloc.c:1714
 prep_new_page mm/page_alloc.c:1722 [inline]
 get_page_from_freelist+0x2b6d/0x2d10 mm/page_alloc.c:3684
 __alloc_frozen_pages_noprof+0x17d/0x370 mm/page_alloc.c:4966
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab+0x8a/0x390 mm/slub.c:2618
 new_slab mm/slub.c:2672 [inline]
 ___slab_alloc+0xc48/0x14c0 mm/slub.c:3858
 __slab_alloc mm/slub.c:3948 [inline]
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 kmem_cache_alloc_noprof+0x273/0x3a0 mm/slub.c:4203
 __proc_create+0x36f/0x8d0 fs/proc/generic.c:427
 proc_create_reg+0x87/0x110 fs/proc/generic.c:554
 proc_create_net_data+0x94/0x1b0 fs/proc/proc_net.c:120
 packet_net_init+0x94/0xb0 net/packet/af_packet.c:4796
 ops_init+0x35c/0x5c0 net/core/net_namespace.c:138
 setup_net+0x234/0x820 net/core/net_namespace.c:364
 copy_net_ns+0x32a/0x590 net/core/net_namespace.c:518
 create_new_namespaces+0x3d3/0x700 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x118/0x160 kernel/nsproxy.c:228
page last free pid 6524 tgid 6511 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1258 [inline]
 __free_frozen_pages+0xaf4/0xcb0 mm/page_alloc.c:2721
 discard_slab mm/slub.c:2716 [inline]
 __put_partials+0x15f/0x1b0 mm/slub.c:3185
 put_cpu_partial+0x17c/0x250 mm/slub.c:3260
 __slab_free+0x2f3/0x3f0 mm/slub.c:4512
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4147 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 kmem_cache_alloc_noprof+0x1b5/0x3a0 mm/slub.c:4203
 getname_flags+0xb4/0x540 fs/namei.c:146
 getname include/linux/fs.h:2852 [inline]
 __do_sys_mknod fs/namei.c:4311 [inline]
 __se_sys_mknod fs/namei.c:4309 [inline]
 __x64_sys_mknod+0x75/0xa0 fs/namei.c:4309
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x7b/0x150 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Memory state around the buggy address:
 ffff88805e2d5f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88805e2d5f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88805e2d6000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88805e2d6080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88805e2d6100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================