================================================================== BUG: KASAN: use-after-free in string_nocheck lib/vsprintf.c:643 [inline] BUG: KASAN: use-after-free in string+0x204/0x290 lib/vsprintf.c:725 Read of size 1 at addr ffff888029bd8a80 by task cifsd/11595 CPU: 0 PID: 11595 Comm: cifsd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x210 mm/kasan/report.c:420 kasan_report+0x10b/0x140 mm/kasan/report.c:524 string_nocheck lib/vsprintf.c:643 [inline] string+0x204/0x290 lib/vsprintf.c:725 vsnprintf+0x10db/0x1c20 lib/vsprintf.c:2805 vscnprintf lib/vsprintf.c:2911 [inline] scnprintf+0xfb/0x180 lib/vsprintf.c:2964 reconn_set_ipaddr_from_hostname+0x152/0x600 fs/smb/client/connect.c:111 __cifs_reconnect+0x1a5/0x870 fs/smb/client/connect.c:444 cifs_reconnect+0x231/0xd20 fs/smb/client/connect.c:618 cifs_readv_from_socket+0x782/0x8d0 include/linux/spinlock.h:-1 cifs_read_from_socket fs/smb/client/connect.c:822 [inline] cifs_demultiplex_thread+0x523/0x35b0 fs/smb/client/connect.c:1232 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Allocated by task 11577: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8e/0xa0 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+0xb0/0x240 mm/slab_common.c:956 kstrdup+0x37/0x70 mm/util.c:61 cifs_get_tcp_session+0xea/0x1ad0 fs/smb/client/connect.c:1740 mount_get_conns+0xb6/0xec0 fs/smb/client/connect.c:3368 is_dfs_mount fs/smb/client/connect.c:3747 [inline] cifs_mount+0x16a/0x13c0 fs/smb/client/connect.c:3952 cifs_smb3_do_mount+0x366/0x760 fs/smb/client/cifsfs.c:948 smb3_get_tree_common fs/smb/client/fs_context.c:712 [inline] smb3_get_tree+0x5a1/0xa90 fs/smb/client/fs_context.c:732 vfs_get_tree+0x88/0x270 fs/super.c:1584 do_new_mount+0x247/0xa40 fs/namespace.c:3078 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Freed by task 11577: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xb6/0x200 mm/slub.c:3700 cifs_put_tcp_session+0x319/0x400 fs/smb/client/connect.c:1712 mount_put_conns+0xb0/0x270 fs/smb/client/connect.c:3349 cifs_mount+0x1097/0x13c0 fs/smb/client/connect.c:4001 cifs_smb3_do_mount+0x366/0x760 fs/smb/client/cifsfs.c:948 smb3_get_tree_common fs/smb/client/fs_context.c:712 [inline] smb3_get_tree+0x5a1/0xa90 fs/smb/client/fs_context.c:732 vfs_get_tree+0x88/0x270 fs/super.c:1584 do_new_mount+0x247/0xa40 fs/namespace.c:3078 do_mount fs/namespace.c:3421 [inline] __do_sys_mount fs/namespace.c:3629 [inline] __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3606 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff888029bd8a80 which belongs to the cache kmalloc-16 of size 16 The buggy address is located 0 bytes inside of 16-byte region [ffff888029bd8a80, ffff888029bd8a90) The buggy address belongs to the physical page: page:ffffea0000a6f600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x29bd8 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea0000c6c440 dead000000000002 ffff8880184413c0 raw: 0000000000000000 0000000080800080 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, tgid 1 (swapper/0), ts 16543432674, free_ts 16537292265 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560 prep_new_page mm/page_alloc.c:2567 [inline] get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2115 alloc_slab_page+0x5d/0x180 mm/slub.c:1799 allocate_slab mm/slub.c:1944 [inline] new_slab+0x87/0x2d0 mm/slub.c:1997 ___slab_alloc+0xbc5/0x1240 mm/slub.c:3154 __slab_alloc mm/slub.c:3240 [inline] slab_alloc_node mm/slub.c:3325 [inline] __kmem_cache_alloc_node+0x126/0x270 mm/slub.c:3398 __do_kmalloc_node mm/slab_common.c:935 [inline] __kmalloc_node_track_caller+0xa0/0x240 mm/slab_common.c:956 kvasprintf+0xe8/0x1a0 lib/kasprintf.c:25 kobject_set_name_vargs+0x5d/0x110 lib/kobject.c:265 dev_set_name+0xdf/0x130 drivers/base/core.c:3485 usb_hub_create_port_device+0x3cc/0xaf0 drivers/usb/core/port.c:710 hub_configure drivers/usb/core/hub.c:1713 [inline] hub_probe+0x2671/0x3790 drivers/usb/core/hub.c:1980 usb_probe_interface+0x6e7/0xcf0 drivers/usb/core/driver.c:395 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x24a/0xb40 drivers/base/dd.c:638 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1487 [inline] free_pcp_prepare mm/page_alloc.c:1537 [inline] free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3509 mm_free_pgd kernel/fork.c:748 [inline] __mmdrop+0xb0/0x480 kernel/fork.c:799 free_bprm+0x122/0x2d0 fs/exec.c:1521 kernel_execve+0x3e5/0x980 fs/exec.c:2047 call_usermodehelper_exec_async+0x207/0x350 kernel/umh.c:113 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Memory state around the buggy address: ffff888029bd8980: fb fb fc fc 00 00 fc fc fa fb fc fc 00 00 fc fc ffff888029bd8a00: fa fb fc fc 00 00 fc fc fb fb fc fc 00 00 fc fc >ffff888029bd8a80: fa fb fc fc 00 00 fc fc fa fb fc fc 00 00 fc fc ^ ffff888029bd8b00: fa fb fc fc fa fb fc fc 00 00 fc fc fa fb fc fc ffff888029bd8b80: 00 00 fc fc 00 03 fc fc 00 03 fc fc 00 03 fc fc ==================================================================