CIFS: VFS: \\127.0.0.1 SMB response too short (0 bytes) ================================================================== BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:643 [inline] BUG: KASAN: use-after-free in string+0x1ec/0x278 lib/vsprintf.c:725 Read of size 1 at addr ffff0000ccef9900 by task cifsd/4741 CPU: 0 PID: 4741 Comm: cifsd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026 Call trace: dump_backtrace+0x1c4/0x1f0 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+0xf4/0x15c lib/dump_stack.c:106 print_address_description+0x88/0x218 mm/kasan/report.c:316 print_report+0x50/0x68 mm/kasan/report.c:420 kasan_report+0xa8/0xfc mm/kasan/report.c:524 __asan_report_load1_noabort+0x2c/0x38 mm/kasan/report_generic.c:348 string_nocheck lib/vsprintf.c:643 [inline] string+0x1ec/0x278 lib/vsprintf.c:725 vsnprintf+0x10ec/0x18d8 lib/vsprintf.c:2805 vscnprintf lib/vsprintf.c:2911 [inline] scnprintf+0xf0/0x17c lib/vsprintf.c:2964 reconn_set_ipaddr_from_hostname+0x130/0x530 fs/smb/client/connect.c:111 __cifs_reconnect+0x184/0x77c fs/smb/client/connect.c:444 cifs_reconnect+0x1d0/0xa88 fs/smb/client/connect.c:-1 cifs_demultiplex_thread+0x18dc/0x2e28 fs/smb/client/connect.c:-1 kthread+0x254/0x2e0 kernel/kthread.c:376 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 Allocated by task 4740: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slab_common.c:936 [inline] __kmalloc_node_track_caller+0xcc/0x174 mm/slab_common.c:956 kstrdup+0x68/0xb0 mm/util.c:61 cifs_get_tcp_session+0xec/0x15ec fs/smb/client/connect.c:1740 mount_get_conns+0xc8/0xc04 fs/smb/client/connect.c:3367 is_dfs_mount fs/smb/client/connect.c:3746 [inline] cifs_mount+0x128/0x1048 fs/smb/client/connect.c:3951 cifs_smb3_do_mount+0x32c/0x680 fs/smb/client/cifsfs.c:948 smb3_get_tree_common fs/smb/client/fs_context.c:712 [inline] smb3_get_tree+0x474/0x88c fs/smb/client/fs_context.c:732 vfs_get_tree+0x90/0x278 fs/super.c:1584 do_new_mount+0x228/0x804 fs/namespace.c:3078 path_mount+0x5ac/0xe6c fs/namespace.c:3408 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount fs/namespace.c:3606 [inline] __arm64_sys_mount+0x4a0/0x5a0 fs/namespace.c:3606 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 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 Freed by task 4740: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xbc/0x21c mm/slub.c:3700 kfree+0xd0/0x1a8 mm/slab_common.c:988 cifs_put_tcp_session+0x2dc/0x3f4 fs/smb/client/connect.c:1712 mount_put_conns+0xbc/0x2a0 fs/smb/client/connect.c:3348 cifs_mount+0xd58/0x1048 fs/smb/client/connect.c:4000 cifs_smb3_do_mount+0x32c/0x680 fs/smb/client/cifsfs.c:948 smb3_get_tree_common fs/smb/client/fs_context.c:712 [inline] smb3_get_tree+0x474/0x88c fs/smb/client/fs_context.c:732 vfs_get_tree+0x90/0x278 fs/super.c:1584 do_new_mount+0x228/0x804 fs/namespace.c:3078 path_mount+0x5ac/0xe6c fs/namespace.c:3408 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount fs/namespace.c:3606 [inline] __arm64_sys_mount+0x4a0/0x5a0 fs/namespace.c:3606 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 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 Last potentially related work creation: kasan_save_stack+0x40/0x70 mm/kasan/common.c:46 __kasan_record_aux_stack+0xc0/0xdc mm/kasan/generic.c:486 kasan_record_aux_stack_noalloc+0x14/0x20 mm/kasan/generic.c:496 kvfree_call_rcu+0xb4/0x6f0 kernel/rcu/tree.c:3405 kernfs_unlink_open_file+0x370/0x41c fs/kernfs/file.c:653 kernfs_fop_release+0x128/0x194 fs/kernfs/file.c:825 __fput+0x1b4/0x7b0 fs/file_table.c:320 ____fput+0x20/0x30 fs/file_table.c:348 task_work_run+0x1f4/0x280 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] do_notify_resume+0x20f8/0x2c84 arch/arm64/kernel/signal.c:1151 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] el0_svc+0x98/0x128 arch/arm64/kernel/entry-common.c:638 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 object at ffff0000ccef9900 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 0 bytes inside of 128-byte region [ffff0000ccef9900, ffff0000ccef9980) The buggy address belongs to the physical page: page:00000000b2cd9d8d refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000ccef9600 pfn:0x10cef9 flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000000200 fffffc00032c9d48 fffffc00032b25c8 ffff0000c0002300 raw: ffff0000ccef9600 000000000010000f 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000ccef9800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000ccef9880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000ccef9900: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000ccef9980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000ccef9a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================