Buffer I/O error on dev loop2, logical block 3245768, async page read
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BUG: KASAN: use-after-free in sysv_new_block+0x618/0x7e4 fs/sysv/balloc.c:113
Read of size 4 at addr ffff0000f7f270c8 by task syz.2.157/4997

CPU: 0 PID: 4997 Comm: syz.2.157 Not tainted 6.1.130-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
 dump_backtrace+0x1c8/0x1f4 arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0x174/0x4c0 mm/kasan/report.c:427
 kasan_report+0xd4/0x130 mm/kasan/report.c:531
 __asan_report_load4_noabort+0x2c/0x38 mm/kasan/report_generic.c:350
 sysv_new_block+0x618/0x7e4 fs/sysv/balloc.c:113
 alloc_branch fs/sysv/itree.c:134 [inline]
 get_block+0x254/0x1360 fs/sysv/itree.c:253
 __block_write_begin_int+0x340/0x13b4 fs/buffer.c:1991
 __block_write_begin fs/buffer.c:2041 [inline]
 block_write_begin+0x98/0x11c fs/buffer.c:2102
 sysv_write_begin+0x44/0x88 fs/sysv/itree.c:487
 page_symlink+0x278/0x4a4 fs/namei.c:5218
 sysv_symlink+0xd4/0x174 fs/sysv/namei.c:86
 vfs_symlink+0x244/0x3a8 fs/namei.c:4471
 do_symlinkat+0x1bc/0x45c fs/namei.c:4500
 __do_sys_symlinkat fs/namei.c:4517 [inline]
 __se_sys_symlinkat fs/namei.c:4514 [inline]
 __arm64_sys_symlinkat+0xa4/0xbc fs/namei.c:4514
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the physical page:
page:000000000c24566c refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x137f27
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000f7f26f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000f7f27000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff0000f7f27080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff0000f7f27100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff0000f7f27180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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