------------[ cut here ]------------ WARNING: CPU: 0 PID: 8209 at fs/inode.c:464 inc_nlink+0x120/0x170 fs/inode.c:464 Modules linked in: CPU: 0 UID: 0 PID: 8209 Comm: syz.2.312 Not tainted 6.14.0-rc7-syzkaller-ga2392f333575 #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+0x120/0x170 fs/inode.c:464 lr : inc_nlink+0x120/0x170 fs/inode.c:464 sp : ffff80009c797b80 x29: ffff80009c797b80 x28: 1fffe0001e3180b4 x27: dfff800000000000 x26: 0000000000000000 x25: 0000000000000000 x24: 000000000000007e x23: 1fffe0001e3180b8 x22: dfff800000000000 x21: 0000000000000000 x20: ffff0000f18c0578 x19: ffff0000f18c05c0 x18: 1fffe000366f1886 x17: ffff80008fbbd000 x16: ffff80008b7c7f00 x15: 0000000000000005 x14: 1ffff000138f2f48 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000080000 x10: 0000000000005e06 x9 : ffff8000a997b000 x8 : 0000000000005e07 x7 : 0000000000000000 x6 : 000000000000003f x5 : 0000000000000040 x4 : ffff80009c797a20 x3 : 0000000000000000 x2 : ffff0000dad7cd38 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: inc_nlink+0x120/0x170 fs/inode.c:464 (P) inode_inc_link_count include/linux/fs.h:2577 [inline] sysv_mkdir+0x2c/0x138 fs/sysv/namei.c:119 vfs_mkdir+0x27c/0x410 fs/namei.c:4313 do_mkdirat+0x250/0x584 fs/namei.c:4336 __do_sys_mkdirat fs/namei.c:4351 [inline] __se_sys_mkdirat fs/namei.c:4349 [inline] __arm64_sys_mkdirat+0x8c/0xa4 fs/namei.c:4349 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 irq event stamp: 1468 hardirqs last enabled at (1467): [] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:85 [inline] hardirqs last enabled at (1467): [] exit_to_kernel_mode+0xdc/0x10c arch/arm64/kernel/entry-common.c:95 hardirqs last disabled at (1468): [] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:488 softirqs last enabled at (1018): [] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32 softirqs last disabled at (1016): [] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19 ---[ end trace 0000000000000000 ]--- ================================================================== BUG: KASAN: use-after-free in sysv_new_block+0x618/0x7e4 fs/sysv/balloc.c:113 Read of size 4 at addr ffff0000f96dc0c8 by task syz.2.312/8209 CPU: 1 UID: 0 PID: 8209 Comm: syz.2.312 Tainted: G W 6.14.0-rc7-syzkaller-ga2392f333575 #0 Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0x198/0x550 mm/kasan/report.c:521 kasan_report+0xd8/0x138 mm/kasan/report.c:634 __asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380 sysv_new_block+0x618/0x7e4 fs/sysv/balloc.c:113 alloc_branch fs/sysv/itree.c:135 [inline] get_block+0x254/0x1350 fs/sysv/itree.c:254 __block_write_begin_int+0x4c4/0x1610 fs/buffer.c:2116 __block_write_begin+0x40/0x54 fs/buffer.c:2165 sysv_prepare_chunk+0x3c/0x50 fs/sysv/itree.c:471 sysv_make_empty+0xb0/0x584 fs/sysv/dir.c:262 sysv_mkdir+0x88/0x138 fs/sysv/namei.c:130 vfs_mkdir+0x27c/0x410 fs/namei.c:4313 do_mkdirat+0x250/0x584 fs/namei.c:4336 __do_sys_mkdirat fs/namei.c:4351 [inline] __se_sys_mkdirat fs/namei.c:4349 [inline] __arm64_sys_mkdirat+0x8c/0xa4 fs/namei.c:4349 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x20b pfn:0x1396dc flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000000000 fffffdffc3e193c8 fffffdffc3e5b748 0000000000000000 raw: 000000000000020b 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000f96dbf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff0000f96dc000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff0000f96dc080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff0000f96dc100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff0000f96dc180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================