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BUG: KASAN: use-after-free in dtMoveEntry fs/jfs/jfs_dtree.c:4232 [inline]
BUG: KASAN: use-after-free in dtSplitPage+0x1a2c/0x3160 fs/jfs/jfs_dtree.c:1561
Write of size 1 at addr ffff88807cfed000 by task syz.4.552/6479

CPU: 1 PID: 6479 Comm: syz.4.552 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 dtMoveEntry fs/jfs/jfs_dtree.c:4232 [inline]
 dtSplitPage+0x1a2c/0x3160 fs/jfs/jfs_dtree.c:1561
 dtSplitUp fs/jfs/jfs_dtree.c:1092 [inline]
 dtInsert+0x1074/0x57e0 fs/jfs/jfs_dtree.c:871
 jfs_symlink+0x8bb/0xfd0 fs/jfs/namei.c:1019
 vfs_symlink+0x245/0x3d0 fs/namei.c:4480
 do_symlinkat+0x1ab/0x6b0 fs/namei.c:4509
 __do_sys_symlinkat fs/namei.c:4526 [inline]
 __se_sys_symlinkat fs/namei.c:4523 [inline]
 __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4523
 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: 0033:0x7fac51f56559
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:00007fac501ad028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 00007fac521dcfa0 RCX: 00007fac51f56559
RDX: 000020000000d580 RSI: ffffffffffffff9c RDI: 000020000000d440
RBP: 00007fac51fedb20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fac521dd038 R14: 00007fac521dcfa0 R15: 00007fff1531c5d8
 </TASK>

The buggy address belongs to the page:
page:ffffea0001f3fb40 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7cfed
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea00013f0508 ffffea0001509a48 0000000000000000
raw: 0000000000000000 0000000000000000 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 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 6485, ts 197720245879, free_ts 197732096923
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 vm_area_alloc_pages mm/vmalloc.c:2876 [inline]
 __vmalloc_area_node mm/vmalloc.c:2932 [inline]
 __vmalloc_node_range+0x4b1/0x8b0 mm/vmalloc.c:3037
 vmalloc_user+0x70/0x80 mm/vmalloc.c:3173
 kcov_mmap+0x27/0x120 kernel/kcov.c:479
 call_mmap include/linux/fs.h:2184 [inline]
 mmap_file+0x5d/0xb0 mm/util.c:1092
 __mmap_region mm/mmap.c:1796 [inline]
 mmap_region+0x1048/0x1730 mm/mmap.c:2933
 do_mmap+0x801/0xe30 mm/mmap.c:1586
 vm_mmap_pgoff+0x1c1/0x2d0 mm/util.c:551
 ksys_mmap_pgoff+0x4e2/0x790 mm/mmap.c:1635
 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 last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396
 __vunmap+0x8e0/0xa80 mm/vmalloc.c:2628
 kcov_mmap+0x89/0x120 kernel/kcov.c:503
 call_mmap include/linux/fs.h:2184 [inline]
 mmap_file+0x5d/0xb0 mm/util.c:1092
 __mmap_region mm/mmap.c:1796 [inline]
 mmap_region+0x1048/0x1730 mm/mmap.c:2933
 do_mmap+0x801/0xe30 mm/mmap.c:1586
 vm_mmap_pgoff+0x1c1/0x2d0 mm/util.c:551
 ksys_mmap_pgoff+0x4e2/0x790 mm/mmap.c:1635
 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

Memory state around the buggy address:
 ffff88807cfecf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88807cfecf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88807cfed000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88807cfed080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807cfed100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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