================================================================== BUG: KASAN: use-after-free in sysv_new_block+0x618/0x7e4 fs/sysv/balloc.c:113 Read of size 4 at addr ffff0000f7aee0c8 by task syz.0.210/5202 CPU: 1 PID: 5202 Comm: syz.0.210 Not tainted 6.1.134-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 generic_perform_write+0x278/0x55c mm/filemap.c:3845 __generic_file_write_iter+0x168/0x388 mm/filemap.c:3973 generic_file_write_iter+0xb8/0x2b4 mm/filemap.c:4005 do_iter_readv_writev fs/read_write.c:-1 [inline] do_iter_write+0x534/0x964 fs/read_write.c:861 vfs_writev fs/read_write.c:934 [inline] do_pwritev+0x1ec/0x334 fs/read_write.c:1031 __do_sys_pwritev2 fs/read_write.c:1090 [inline] __se_sys_pwritev2 fs/read_write.c:1081 [inline] __arm64_sys_pwritev2+0xd4/0x108 fs/read_write.c:1081 __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:000000004f7d4782 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x137aee 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: ffff0000f7aedf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff0000f7aee000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff0000f7aee080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff0000f7aee100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff0000f7aee180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== ------------[ cut here ]------------ WARNING: CPU: 1 PID: 5202 at fs/inode.c:389 inc_nlink+0x128/0x154 fs/inode.c:389 Modules linked in: CPU: 1 PID: 5202 Comm: syz.0.210 Tainted: G B 6.1.134-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 : ffff8000217d7b70 x29: ffff8000217d7b70 x28: dfff800000000000 x27: 0000000000000000 x26: 1fffe0001ac21b8d x25: ffff80001271be88 x24: 00000000000001c0 x23: 1fffe0001c64e8b9 x22: dfff800000000000 x21: 0000000000000007 x20: ffff0000e3274580 x19: ffff0000e32745c8 x18: 1ffff000042faed4 x17: 0000000000000000 x16: ffff800012329d14 x15: 0000000000000002 x14: 00000000ffff8000 x13: 00000000c061f15f x12: 0000000000080000 x11: 00000000000012e6 x10: ffff800022bfd000 x9 : ffff800008aad2c0 x8 : 00000000000012e7 x7 : 0000000000000000 x6 : 000000000000003f x5 : 0000000000000040 x4 : 0000000000000001 x3 : 00000000000001c0 x2 : ffff0000e3290bc0 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+0x334/0x4e4 fs/namei.c:4106 do_mkdirat+0x220/0x510 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+0x58/0x168 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 irq event stamp: 7211 hardirqs last enabled at (7211): [] raw_spin_rq_unlock_irq kernel/sched/sched.h:1367 [inline] hardirqs last enabled at (7211): [] finish_lock_switch+0xbc/0x1e8 kernel/sched/core.c:5003 hardirqs last disabled at (7210): [] __schedule+0x2a4/0x1d44 kernel/sched/core.c:6459 softirqs last enabled at (6836): [] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32 softirqs last disabled at (6834): [] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19 ---[ end trace 0000000000000000 ]---