syzbot

==================================================================
BUG: KASAN: slab-use-after-free in strlen+0x57/0x70 lib/string.c:420
Read of size 1 at addr ffff8880334b0000 by task syz.5.1156/11313

CPU: 1 UID: 0 PID: 11313 Comm: syz.5.1156 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 strlen+0x57/0x70 lib/string.c:420
 __fortify_strlen include/linux/fortify-string.h:268 [inline]
 seq_escape_str include/linux/seq_file.h:146 [inline]
 seq_escape include/linux/seq_file.h:162 [inline]
 seq_show_option+0x61/0x90 include/linux/seq_file.h:272
 f2fs_show_quota_options fs/f2fs/super.c:2246 [inline]
 f2fs_show_options+0xc50/0x1990 fs/f2fs/super.c:2431
 show_vfsmnt+0x545/0x690 fs/proc_namespace.c:129
 seq_read_iter+0x9bb/0xe20 fs/seq_file.c:272
 new_sync_read fs/read_write.c:491 [inline]
 vfs_read+0x55a/0xa30 fs/read_write.c:572
 ksys_pread64 fs/read_write.c:763 [inline]
 __do_sys_pread64 fs/read_write.c:771 [inline]
 __se_sys_pread64 fs/read_write.c:768 [inline]
 __x64_sys_pread64+0x193/0x220 fs/read_write.c:768
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f380eb8f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f380faed038 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
RAX: ffffffffffffffda RBX: 00007f380ede6090 RCX: 00007f380eb8f749
RDX: 0000000000001000 RSI: 0000200000002240 RDI: 0000000000000009
RBP: 00007f380ec13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000000ff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f380ede6128 R14: 00007f380ede6090 R15: 00007ffe3d747e18
 </TASK>

Allocated by task 11266:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5652 [inline]
 __kmalloc_node_track_caller_noprof+0x575/0x820 mm/slub.c:5759
 __kmemdup_nul mm/util.c:64 [inline]
 kstrdup+0x42/0x100 mm/util.c:84
 f2fs_apply_quota_options fs/f2fs/super.c:1575 [inline]
 f2fs_apply_options+0x1297/0x1f00 fs/f2fs/super.c:1715
 f2fs_fill_super+0x258d/0x6ec0 fs/f2fs/super.c:4949
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691
 vfs_get_tree+0x92/0x2a0 fs/super.c:1751
 fc_mount fs/namespace.c:1209 [inline]
 do_new_mount_fc fs/namespace.c:3646 [inline]
 do_new_mount+0x302/0xa10 fs/namespace.c:3722
 do_mount fs/namespace.c:4045 [inline]
 __do_sys_mount fs/namespace.c:4234 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4211
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 11266:
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6663 [inline]
 kfree+0x1c0/0x660 mm/slub.c:6871
 __f2fs_remount fs/f2fs/super.c:2998 [inline]
 f2fs_reconfigure+0x568/0x1770 fs/f2fs/super.c:5398
 reconfigure_super+0x227/0x880 fs/super.c:1077
 do_remount fs/namespace.c:3274 [inline]
 path_mount+0xd29/0xff0 fs/namespace.c:4024
 do_mount fs/namespace.c:4045 [inline]
 __do_sys_mount fs/namespace.c:4234 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4211
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880334b0000
 which belongs to the cache kmalloc-16 of size 16
The buggy address is located 0 bytes inside of
 freed 16-byte region [ffff8880334b0000, ffff8880334b0010)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x334b0
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88813fe26640 ffffea0000baf900 dead000000000002
raw: 0000000000000000 0000000000800080 00000000f5000000 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 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 5825, tgid 5825 (syz-executor), ts 125816652236, free_ts 125816563208
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846
 prep_new_page mm/page_alloc.c:1854 [inline]
 get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
 alloc_slab_page mm/slub.c:3077 [inline]
 allocate_slab+0x7a/0x3b0 mm/slub.c:3248
 new_slab mm/slub.c:3302 [inline]
 ___slab_alloc+0xf2b/0x1960 mm/slub.c:4651
 __slab_alloc+0x65/0x100 mm/slub.c:4774
 __slab_alloc_node mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:5246 [inline]
 __do_kmalloc_node mm/slub.c:5651 [inline]
 __kvmalloc_node_noprof+0x6b6/0x920 mm/slub.c:7129
 xt_jumpstack_alloc net/netfilter/x_tables.c:1356 [inline]
 xt_replace_table+0x18a/0x7c0 net/netfilter/x_tables.c:1395
 __do_replace+0x15a/0x980 net/ipv6/netfilter/ip6_tables.c:1081
 do_replace net/ipv6/netfilter/ip6_tables.c:1158 [inline]
 do_ip6t_set_ctl+0xa16/0xce0 net/ipv6/netfilter/ip6_tables.c:1644
 nf_setsockopt+0x26f/0x290 net/netfilter/nf_sockopt.c:101
 do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2353
 __sys_setsockopt net/socket.c:2378 [inline]
 __do_sys_setsockopt net/socket.c:2384 [inline]
 __se_sys_setsockopt net/socket.c:2381 [inline]
 __x64_sys_setsockopt+0x13f/0x1b0 net/socket.c:2381
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5825 tgid 5825 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0xbc8/0xd30 mm/page_alloc.c:2943
 ___free_pages_bulk mm/kasan/shadow.c:333 [inline]
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:385 [inline]
 __kasan_populate_vmalloc+0x137/0x1d0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:579 [inline]
 alloc_vmap_area+0xdc4/0x14e0 mm/vmalloc.c:2124
 __get_vm_area_node+0x1f8/0x300 mm/vmalloc.c:3219
 __vmalloc_node_range_noprof+0x371/0x16a0 mm/vmalloc.c:4011
 __vmalloc_node_noprof mm/vmalloc.c:4111 [inline]
 vzalloc_noprof+0xb2/0xf0 mm/vmalloc.c:4189
 __do_replace+0xab/0x980 net/ipv6/netfilter/ip6_tables.c:1063
 do_replace net/ipv6/netfilter/ip6_tables.c:1158 [inline]
 do_ip6t_set_ctl+0xa16/0xce0 net/ipv6/netfilter/ip6_tables.c:1644
 nf_setsockopt+0x26f/0x290 net/netfilter/nf_sockopt.c:101
 do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2353
 __sys_setsockopt net/socket.c:2378 [inline]
 __do_sys_setsockopt net/socket.c:2384 [inline]
 __se_sys_setsockopt net/socket.c:2381 [inline]
 __x64_sys_setsockopt+0x13f/0x1b0 net/socket.c:2381
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880334aff00: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
 ffff8880334aff80: fa fb fb fb fc fc fc fc 00 00 00 00 fc fc fc fc
>ffff8880334b0000: fa fb fc fc 00 03 fc fc 00 00 fc fc 00 00 fc fc
                   ^
 ffff8880334b0080: 00 07 fc fc 00 00 fc fc 00 00 fc fc 00 03 fc fc
 ffff8880334b0100: 00 00 fc fc 00 00 fc fc 00 00 fc fc 00 00 fc fc
==================================================================