================================================================== 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 ffff88802e369e00 by task cifsd/4487 CPU: 0 PID: 4487 Comm: cifsd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 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 4486: 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:3367 is_dfs_mount fs/smb/client/connect.c:3746 [inline] cifs_mount+0x16a/0x13c0 fs/smb/client/connect.c:3951 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 4486: 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:3348 cifs_mount+0x1097/0x13c0 fs/smb/client/connect.c:4000 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 ffff88802e369e00 which belongs to the cache kmalloc-16 of size 16 The buggy address is located 0 bytes inside of 16-byte region [ffff88802e369e00, ffff88802e369e10) The buggy address belongs to the physical page: page:ffffea0000b8da40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2e369 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 0000000000000000 dead000000000122 ffff8880174413c0 raw: 0000000000000000 0000000000800080 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 4280, tgid 4280 (syz-executor), ts 75413683065, free_ts 75406857587 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_pages_node include/linux/gfp.h:237 [inline] alloc_slab_page+0x4f/0x180 mm/slub.c:1801 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+0xa2/0x240 mm/slab_common.c:943 kmalloc_node include/linux/slab.h:589 [inline] kvmalloc_node+0x6c/0x180 mm/util.c:581 xt_jumpstack_alloc net/netfilter/x_tables.c:1377 [inline] xt_replace_table+0x176/0x790 net/netfilter/x_tables.c:1416 __do_replace+0x16a/0x970 net/ipv4/netfilter/ip_tables.c:1064 do_replace net/ipv4/netfilter/ip_tables.c:1141 [inline] do_ipt_set_ctl+0xb34/0xe00 net/ipv4/netfilter/ip_tables.c:1634 nf_setsockopt+0x25f/0x280 net/netfilter/nf_sockopt.c:101 __sys_setsockopt+0x2bf/0x3d0 net/socket.c:2288 __do_sys_setsockopt net/socket.c:2299 [inline] __se_sys_setsockopt net/socket.c:2296 [inline] __x64_sys_setsockopt+0xb1/0xc0 net/socket.c:2296 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 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 free_slab mm/slub.c:2036 [inline] discard_slab mm/slub.c:2042 [inline] __unfreeze_partials+0x188/0x1e0 mm/slub.c:2591 put_cpu_partial+0x17c/0x250 mm/slub.c:2667 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4b/0x490 mm/slab.h:737 slab_alloc_node mm/slub.c:3359 [inline] slab_alloc mm/slub.c:3367 [inline] __kmem_cache_alloc_lru mm/slub.c:3374 [inline] kmem_cache_alloc+0x18b/0x2f0 mm/slub.c:3383 getname_flags+0xb7/0x500 fs/namei.c:139 vfs_fstatat fs/stat.c:266 [inline] __do_sys_newfstatat fs/stat.c:437 [inline] __se_sys_newfstatat fs/stat.c:431 [inline] __x64_sys_newfstatat+0x16f/0x240 fs/stat.c:431 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 Memory state around the buggy address: ffff88802e369d00: 00 00 fc fc 00 00 fc fc 00 00 fc fc fa fb fc fc ffff88802e369d80: 00 00 fc fc 00 00 fc fc 00 00 fc fc fa fb fc fc >ffff88802e369e00: fa fb fc fc fa fb fc fc fa fb fc fc 00 04 fc fc ^ ffff88802e369e80: fa fb fc fc fa fb fc fc 00 06 fc fc fa fb fc fc ffff88802e369f00: fa fb fc fc fa fb fc fc fa fb fc fc fa fb fc fc ==================================================================