attempt to access beyond end of device loop1: rw=0, want=6491538, limit=128 Buffer I/O error on dev loop1, logical block 3245768, async page read ================================================================== BUG: KASAN: use-after-free in sysv_new_inode+0x10b4/0x1240 fs/sysv/ialloc.c:153 Read of size 2 at addr ffff8880691e21ce by task syz.1.176/5188 CPU: 0 PID: 5188 Comm: syz.1.176 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x168/0x230 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 sysv_new_inode+0x10b4/0x1240 fs/sysv/ialloc.c:153 sysv_symlink+0x9b/0x150 fs/sysv/namei.c:80 vfs_symlink+0x247/0x3d0 fs/namei.c:4429 do_symlinkat+0x1be/0x6c0 fs/namei.c:4458 __do_sys_symlink fs/namei.c:4480 [inline] __se_sys_symlink fs/namei.c:4478 [inline] __x64_sys_symlink+0x7a/0x90 fs/namei.c:4478 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: 0033:0x7fcdfeb70ba9 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:00007fcdfcdd8038 EFLAGS: 00000246 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 00007fcdfedb7fa0 RCX: 00007fcdfeb70ba9 RDX: 0000000000000000 RSI: 00002000000059c0 RDI: 00002000000049c0 RBP: 00007fcdfebf3e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcdfedb8038 R14: 00007fcdfedb7fa0 R15: 00007fffc591bb58 The buggy address belongs to the page: page:ffffea0001a47880 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x100 pfn:0x691e2 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000000 ffffea00016c1e08 ffffea0001e59188 0000000000000000 raw: 0000000000000100 0000000000000001 00000000ffffff7f 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 0, migratetype Movable, gfp_mask 0x1100cca(GFP_HIGHUSER_MOVABLE), pid 5162, ts 124429898281, free_ts 124742155554 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5487 alloc_pages_vma+0x393/0x7c0 mm/mempolicy.c:2146 shmem_alloc_page mm/shmem.c:1586 [inline] shmem_alloc_and_acct_page+0x427/0xb70 mm/shmem.c:1611 shmem_getpage_gfp+0x14f4/0x2d40 mm/shmem.c:1906 shmem_getpage mm/shmem.c:151 [inline] shmem_write_begin+0xcd/0x1a0 mm/shmem.c:2474 generic_perform_write+0x2aa/0x530 mm/filemap.c:3785 __generic_file_write_iter+0x25f/0x4e0 mm/filemap.c:3912 generic_file_write_iter+0xa6/0x1b0 mm/filemap.c:3944 __kernel_write+0x4f9/0x930 fs/read_write.c:539 __dump_emit+0x243/0x360 fs/coredump.c:943 dump_user_range+0x84/0x340 fs/coredump.c:1017 elf_core_dump+0x2ff7/0x3530 fs/binfmt_elf.c:2285 do_coredump+0x1419/0x2960 fs/coredump.c:894 get_signal+0x40a/0x12c0 kernel/signal.c:2886 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 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_list+0x122/0x7e0 mm/page_alloc.c:3433 release_pages+0x184b/0x1bb0 mm/swap.c:963 __pagevec_release+0x6d/0xe0 mm/swap.c:983 pagevec_release include/linux/pagevec.h:81 [inline] shmem_undo_range+0x5cb/0x1880 mm/shmem.c:964 shmem_truncate_range mm/shmem.c:1063 [inline] shmem_evict_inode+0x20d/0xa00 mm/shmem.c:1145 evict+0x485/0x870 fs/inode.c:647 __dentry_kill+0x431/0x650 fs/dcache.c:586 dentry_kill+0xb8/0x290 fs/dcache.c:-1 dput+0xd8/0x1a0 fs/dcache.c:893 __fput+0x5ee/0x930 fs/file_table.c:319 task_work_run+0x125/0x1a0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 Memory state around the buggy address: ffff8880691e2080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880691e2100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8880691e2180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ^ ffff8880691e2200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880691e2280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================