CIFS: Attempting to mount //127.0.0.1/share
==================================================================
BUG: KASAN: slab-use-after-free in cifs_free_hash+0xcc/0x100 fs/smb/client/misc.c:1207
Write of size 8 at addr ffff88807b1c2460 by task syz.1.129/6490

CPU: 0 PID: 6490 Comm: syz.1.129 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 cifs_free_hash+0xcc/0x100 fs/smb/client/misc.c:1207
 cifs_crypto_secmech_release+0x56/0x110 fs/smb/client/cifsencrypt.c:850
 cifs_put_tcp_session+0x20b/0x320 fs/smb/client/connect.c:1699
 cifs_mount_put_conns+0xb4/0x280 fs/smb/client/connect.c:3439
 cifs_mount+0xdc/0x650 fs/smb/client/connect.c:3750
 cifs_smb3_do_mount+0x2e5/0x710 fs/smb/client/cifsfs.c:950
 smb3_get_tree_common fs/smb/client/fs_context.c:785 [inline]
 smb3_get_tree+0x5a5/0xa90 fs/smb/client/fs_context.c:805
 vfs_get_tree+0x8c/0x280 fs/super.c:1772
 do_new_mount+0x24a/0xa40 fs/namespace.c:3386
 do_mount fs/namespace.c:3726 [inline]
 __do_sys_mount fs/namespace.c:3935 [inline]
 __se_sys_mount+0x2e7/0x3d0 fs/namespace.c:3912
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd324f9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd325d9a028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fd325226090 RCX: 00007fd324f9e159
RDX: 0000200000000400 RSI: 0000200000000300 RDI: 0000200000000200
RBP: 00007fd32503506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd325226128 R14: 00007fd325226090 R15: 00007ffe874bff98
 </TASK>

Allocated by task 6490:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 cifs_get_tcp_session+0xb5/0x1a10 fs/smb/client/connect.c:1724
 cifs_mount_get_session+0xae/0x440 fs/smb/client/connect.c:3464
 get_session fs/smb/client/dfs.c:62 [inline]
 dfs_mount_share+0x1e9/0x7b0 fs/smb/client/dfs.c:285
 cifs_mount+0xbc/0x650 fs/smb/client/connect.c:3720
 cifs_smb3_do_mount+0x2e5/0x710 fs/smb/client/cifsfs.c:950
 smb3_get_tree_common fs/smb/client/fs_context.c:785 [inline]
 smb3_get_tree+0x5a5/0xa90 fs/smb/client/fs_context.c:805
 vfs_get_tree+0x8c/0x280 fs/super.c:1772
 do_new_mount+0x24a/0xa40 fs/namespace.c:3386
 do_mount fs/namespace.c:3726 [inline]
 __do_sys_mount fs/namespace.c:3935 [inline]
 __se_sys_mount+0x2e7/0x3d0 fs/namespace.c:3912
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 6494:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843
 clean_demultiplex_info+0xb63/0xd60 fs/smb/client/connect.c:1078
 cifs_demultiplex_thread+0x274e/0x2a70 fs/smb/client/connect.c:1373
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

The buggy address belongs to the object at ffff88807b1c2000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 1120 bytes inside of
 freed 4096-byte region [ffff88807b1c2000, ffff88807b1c3000)

The buggy address belongs to the physical page:
page:ffffea0001ec7000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7b1c0
head:ffffea0001ec7000 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888017c42140 ffffea0000b3d400 dead000000000002
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5146, tgid 5146 (udevd), ts 32506140439, free_ts 27532292334
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1582
 prep_new_page mm/page_alloc.c:1589 [inline]
 get_page_from_freelist+0x2181/0x22a0 mm/page_alloc.c:3221
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4501
 alloc_slab_page+0x5d/0x180 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2081
 ___slab_alloc+0xc5c/0x12f0 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 __kmem_cache_alloc_node+0x11f/0x250 mm/slub.c:3534
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc+0xa7/0x240 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 tomoyo_realpath_from_path+0xe6/0x5c0 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x224/0x460 security/tomoyo/file.c:771
 security_file_open+0x62/0xa0 security/security.c:2968
 do_dentry_open+0x32b/0x14b0 fs/open.c:916
 do_open fs/namei.c:3683 [inline]
 path_openat+0x284f/0x3270 fs/namei.c:3844
 do_filp_open+0x1f2/0x430 fs/namei.c:3871
 do_sys_openat2+0x134/0x1d0 fs/open.c:1422
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_openat fs/open.c:1453 [inline]
 __se_sys_openat fs/open.c:1448 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1448
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1182 [inline]
 free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459
 free_contig_range+0xa1/0x150 mm/page_alloc.c:6421
 destroy_args+0x7d/0x840 mm/debug_vm_pgtable.c:1015
 debug_vm_pgtable+0x411/0x440 mm/debug_vm_pgtable.c:1400
 do_one_initcall+0x242/0x790 init/main.c:1210
 do_initcall_level+0x13d/0x1f0 init/main.c:1272
 do_initcalls+0x69/0xd0 init/main.c:1288
 kernel_init_freeable+0x3d9/0x560 init/main.c:1525
 kernel_init+0x1d/0x1c0 init/main.c:1415
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

Memory state around the buggy address:
 ffff88807b1c2300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807b1c2380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807b1c2400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff88807b1c2480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807b1c2500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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