================================================================== BUG: KASAN: use-after-free in strlen+0x53/0x60 lib/string.c:581 Read of size 1 at addr ffff888059892f40 by task cifsd/6906 CPU: 1 PID: 6906 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+0x188/0x250 lib/dump_stack.c:106 print_address_description+0x60/0x2d0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0xdf/0x130 mm/kasan/report.c:451 strlen+0x53/0x60 lib/string.c:581 reconn_set_ipaddr_from_hostname+0xc5/0x580 fs/cifs/connect.c:100 __cifs_reconnect fs/cifs/connect.c:288 [inline] cifs_reconnect+0x470/0x1350 fs/cifs/connect.c:447 cifs_readv_from_socket+0x7c4/0x8b0 fs/cifs/connect.c:-1 cifs_read_from_socket fs/cifs/connect.c:626 [inline] cifs_demultiplex_thread+0x53b/0x35b0 fs/cifs/connect.c:989 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Allocated by task 6899: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc+0xaf/0xe0 mm/kasan/common.c:522 kstrdup+0x32/0x70 mm/util.c:60 cifs_get_tcp_session+0xde/0x18f0 fs/cifs/connect.c:1431 mount_get_conns+0xc3/0xe00 fs/cifs/connect.c:2988 is_dfs_mount fs/cifs/connect.c:3354 [inline] cifs_mount+0x162/0x1380 fs/cifs/connect.c:3549 cifs_smb3_do_mount+0x366/0x760 fs/cifs/cifsfs.c:895 smb3_get_tree_common fs/cifs/fs_context.c:708 [inline] smb3_get_tree+0x59a/0xa80 fs/cifs/fs_context.c:726 vfs_get_tree+0x88/0x270 fs/super.c:1530 do_new_mount+0x247/0xa40 fs/namespace.c:3034 do_mount fs/namespace.c:3377 [inline] __do_sys_mount fs/namespace.c:3585 [inline] __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Freed by task 6899: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1710 [inline] slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736 slab_free mm/slub.c:3504 [inline] kfree+0xef/0x2a0 mm/slub.c:4564 cifs_put_tcp_session+0x2e1/0x3d0 fs/cifs/connect.c:1404 mount_put_conns+0xb0/0x270 fs/cifs/connect.c:2969 cifs_mount+0xbf5/0x1380 fs/cifs/connect.c:3597 cifs_smb3_do_mount+0x366/0x760 fs/cifs/cifsfs.c:895 smb3_get_tree_common fs/cifs/fs_context.c:708 [inline] smb3_get_tree+0x59a/0xa80 fs/cifs/fs_context.c:726 vfs_get_tree+0x88/0x270 fs/super.c:1530 do_new_mount+0x247/0xa40 fs/namespace.c:3034 do_mount fs/namespace.c:3377 [inline] __do_sys_mount fs/namespace.c:3585 [inline] __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 The buggy address belongs to the object at ffff888059892f40 which belongs to the cache kmalloc-16 of size 16 The buggy address is located 0 bytes inside of 16-byte region [ffff888059892f40, ffff888059892f50) The buggy address belongs to the page: page:ffffea0001662480 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888059892f00 pfn:0x59892 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffffea0000919cc0 0000001c0000001c ffff888016c413c0 raw: ffff888059892f00 000000008080007d 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 4185, ts 86632109300, free_ts 86587279173 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501 __alloc_pages_node include/linux/gfp.h:570 [inline] alloc_slab_page mm/slub.c:1782 [inline] allocate_slab mm/slub.c:1917 [inline] new_slab+0xb6/0x4b0 mm/slub.c:1980 ___slab_alloc+0x807/0xdd0 mm/slub.c:3013 __slab_alloc mm/slub.c:3100 [inline] slab_alloc_node mm/slub.c:3191 [inline] __kmalloc_node+0x142/0x3a0 mm/slub.c:4456 kmalloc_node include/linux/slab.h:630 [inline] kvmalloc_node+0x84/0x130 mm/util.c:619 xt_jumpstack_alloc net/netfilter/x_tables.c:1377 [inline] xt_replace_table+0x160/0x750 net/netfilter/x_tables.c:1416 __do_replace+0x16f/0xa00 net/ipv6/netfilter/ip6_tables.c:1081 do_replace net/ipv6/netfilter/ip6_tables.c:1158 [inline] do_ip6t_set_ctl+0xaa4/0xd90 net/ipv6/netfilter/ip6_tables.c:1643 nf_setsockopt+0x25f/0x280 net/netfilter/nf_sockopt.c:101 ipv6_setsockopt+0x20ba/0x3cc0 net/ipv6/ipv6_sockglue.c:1014 tcp_setsockopt+0x229/0x1e60 net/ipv4/tcp.c:3722 __sys_setsockopt+0x2bf/0x3d0 net/socket.c:2213 __do_sys_setsockopt net/socket.c:2224 [inline] __se_sys_setsockopt net/socket.c:2221 [inline] __x64_sys_setsockopt+0xb1/0xc0 net/socket.c:2221 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1340 [inline] free_pcp_prepare mm/page_alloc.c:1391 [inline] free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317 free_unref_page_list+0x119/0x830 mm/page_alloc.c:3433 release_pages+0x185f/0x1bd0 mm/swap.c:963 tlb_batch_pages_flush mm/mmu_gather.c:50 [inline] tlb_flush_mmu_free mm/mmu_gather.c:241 [inline] tlb_flush_mmu mm/mmu_gather.c:248 [inline] tlb_finish_mmu+0x1b4/0x370 mm/mmu_gather.c:371 exit_mmap+0x3d0/0x640 mm/mmap.c:3218 __mmput+0x115/0x390 kernel/fork.c:1128 exit_mm+0x632/0x7b0 kernel/exit.c:557 do_exit+0x5b8/0x2110 kernel/exit.c:877 do_group_exit+0x12c/0x2f0 kernel/exit.c:1004 __do_sys_exit_group kernel/exit.c:1015 [inline] __se_sys_exit_group kernel/exit.c:1013 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1013 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Memory state around the buggy address: ffff888059892e00: 00 00 fc fc fa fb fc fc fa fb fc fc 00 00 fc fc ffff888059892e80: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc >ffff888059892f00: fb fb fc fc fa fb fc fc fa fb fc fc 00 06 fc fc ^ ffff888059892f80: 00 06 fc fc 00 05 fc fc 00 00 fc fc fa fb fc fc ffff888059893000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc ==================================================================