------------[ cut here ]------------ WARNING: CPU: 0 PID: 4902 at fs/inode.c:389 inc_nlink+0x128/0x154 fs/inode.c:389 Modules linked in: CPU: 0 PID: 4902 Comm: syz.3.93 Not tainted 6.1.139-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : inc_nlink+0x128/0x154 fs/inode.c:389 lr : inc_nlink+0x128/0x154 fs/inode.c:389 sp : ffff800021437b90 x29: ffff800021437b90 x28: dfff800000000000 x27: 0000000000000000 x26: 1fffe0001eaa780c x25: ffff800011d04e88 x24: 0000000000000000 x23: 1fffe0001eaa7810 x22: dfff800000000000 x21: 0000000000000000 x20: ffff0000f553c038 x19: ffff0000f553c080 x18: 0000000000000000 x17: ffff8000181a0000 x16: ffff8000082d241c x15: 0000000000000002 x14: 00000000ffff8000 x13: 00000000c564a726 x12: 0000000000080000 x11: 0000000000008737 x10: ffff8000260ab000 x9 : ffff8000089fbd98 x8 : 0000000000008738 x7 : 0000000000000000 x6 : 000000000000003f x5 : 0000000000000040 x4 : 0000000000000001 x3 : 0000000000000000 x2 : ffff0000de96e468 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: inc_nlink+0x128/0x154 fs/inode.c:389 inode_inc_link_count include/linux/fs.h:2576 [inline] sysv_mkdir+0x2c/0x138 fs/sysv/namei.c:119 vfs_mkdir+0x314/0x4d4 fs/namei.c:4106 do_mkdirat+0x1b4/0x3e0 fs/namei.c:4131 __do_sys_mkdirat fs/namei.c:4146 [inline] __se_sys_mkdirat fs/namei.c:4144 [inline] __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4144 __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+0x58/0x138 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 irq event stamp: 208 hardirqs last enabled at (207): [] kasan_quarantine_put+0xc4/0x204 mm/kasan/quarantine.c:242 hardirqs last disabled at (208): [] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405 softirqs last enabled at (132): [] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32 softirqs last disabled at (130): [] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19 ---[ end trace 0000000000000000 ]--- ================================================================== BUG: KASAN: use-after-free in sysv_new_inode+0xd8c/0xf04 fs/sysv/ialloc.c:153 Read of size 2 at addr ffff0000f71f61ce by task syz.3.93/4902 CPU: 0 PID: 4902 Comm: syz.3.93 Tainted: G W 6.1.139-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+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf8/0x160 lib/dump_stack.c:106 print_address_description+0x88/0x220 mm/kasan/report.c:316 print_report+0x50/0x68 mm/kasan/report.c:427 kasan_report+0xa8/0x100 mm/kasan/report.c:531 __asan_report_load2_noabort+0x2c/0x38 mm/kasan/report_generic.c:349 sysv_new_inode+0xd8c/0xf04 fs/sysv/ialloc.c:153 sysv_mkdir+0x44/0x138 fs/sysv/namei.c:121 vfs_mkdir+0x314/0x4d4 fs/namei.c:4106 do_mkdirat+0x1b4/0x3e0 fs/namei.c:4131 __do_sys_mkdirat fs/namei.c:4146 [inline] __se_sys_mkdirat fs/namei.c:4144 [inline] __arm64_sys_mkdirat+0x90/0xa8 fs/namei.c:4144 __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+0x58/0x138 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:0000000024c5e262 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x1371f6 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: ffff0000f71f6080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff0000f71f6100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff0000f71f6180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff0000f71f6200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff0000f71f6280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== sysv_free_block: flc_count > flc_size sysv_free_block: flc_count > flc_size sysv_free_block: flc_count > flc_size sysv_free_block: flc_count > flc_size sysv_free_block: flc_count > flc_size sysv_free_block: flc_count > flc_size sysv_free_block: flc_count > flc_size sysv_free_block: flc_count > flc_size sysv_free_block: flc_count > flc_size sysv_free_block: flc_count > flc_size sysv_free_inode: inode 0,1,2 or nonexistent inode