syzbot

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BUG: KASAN: slab-use-after-free in hlist_add_head include/linux/list.h:1026 [inline]
BUG: KASAN: slab-use-after-free in binder_add_device+0x5f/0xa0 drivers/android/binder.c:6932
Write of size 8 at addr ffff888142ba6408 by task syz-executor/5920

CPU: 1 UID: 0 PID: 5920 Comm: syz-executor Not tainted 6.14.0-rc5-syzkaller-01215-g89d75c4c67ac #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0x16e/0x5b0 mm/kasan/report.c:521
 kasan_report+0x143/0x180 mm/kasan/report.c:634
 hlist_add_head include/linux/list.h:1026 [inline]
 binder_add_device+0x5f/0xa0 drivers/android/binder.c:6932
 binderfs_binder_device_create+0x878/0xab0 drivers/android/binderfs.c:210
 binderfs_fill_super+0x96e/0xe70 drivers/android/binderfs.c:729
 vfs_get_super fs/super.c:1280 [inline]
 get_tree_nodev+0xb7/0x140 fs/super.c:1299
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3560
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fad2db8e90a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007ffd9ea9b3e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fad2dc0e663 RCX: 00007fad2db8e90a
RDX: 00007fad2dc1dda7 RSI: 00007fad2dc0e663 RDI: 00007fad2dc1dda7
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fad2dc28480
R13: 00007ffd9ea9b468 R14: 0000000000000009 R15: 0000000000000000
 </TASK>

Allocated by task 5830:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4325
 kmalloc_noprof include/linux/slab.h:901 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 binderfs_binder_device_create+0x171/0xab0 drivers/android/binderfs.c:147
 binderfs_fill_super+0x96e/0xe70 drivers/android/binderfs.c:729
 vfs_get_super fs/super.c:1280 [inline]
 get_tree_nodev+0xb7/0x140 fs/super.c:1299
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3560
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4088
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5830:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2353 [inline]
 slab_free mm/slub.c:4609 [inline]
 kfree+0x196/0x430 mm/slub.c:4757
 evict+0x4e8/0x9a0 fs/inode.c:796
 __dentry_kill+0x20d/0x630 fs/dcache.c:643
 shrink_kill+0xa9/0x2c0 fs/dcache.c:1088
 shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1115
 shrink_dcache_parent+0xcb/0x3b0
 do_one_tree+0x23/0xe0 fs/dcache.c:1578
 shrink_dcache_for_umount+0xb4/0x180 fs/dcache.c:1595
 generic_shutdown_super+0x6a/0x2d0 fs/super.c:620
 kill_anon_super fs/super.c:1237 [inline]
 kill_litter_super+0x76/0xb0 fs/super.c:1247
 binderfs_kill_super+0x44/0x90 drivers/android/binderfs.c:791
 deactivate_locked_super+0xc4/0x130 fs/super.c:473
 cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1413
 task_work_run+0x24f/0x310 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0xa2a/0x28e0 kernel/exit.c:938
 do_group_exit+0x207/0x2c0 kernel/exit.c:1087
 get_signal+0x168c/0x1720 kernel/signal.c:3036
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888142ba6400
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 8 bytes inside of
 freed 512-byte region [ffff888142ba6400, ffff888142ba6600)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x142ba4
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff88801b041c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff88801b041c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 057ff00000000002 ffffea00050ae901 ffffffffffffffff 0000000000000000
head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 6844203360, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x292/0x710 mm/page_alloc.c:4739
 alloc_pages_mpol+0x311/0x660 mm/mempolicy.c:2270
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab+0x8f/0x3a0 mm/slub.c:2587
 new_slab mm/slub.c:2640 [inline]
 ___slab_alloc+0xc27/0x14a0 mm/slub.c:3826
 __slab_alloc+0x58/0xa0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 __kmalloc_cache_noprof+0x27b/0x390 mm/slub.c:4320
 kmalloc_noprof include/linux/slab.h:901 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 device_private_init drivers/base/core.c:3510 [inline]
 device_add+0xc1/0xbf0 drivers/base/core.c:3561
 device_create_groups_vargs drivers/base/core.c:4347 [inline]
 device_create+0x257/0x2e0 drivers/base/core.c:4386
 bdi_register_va+0x8b/0x770 mm/backing-dev.c:1094
 bdi_register+0xd5/0x120 mm/backing-dev.c:1126
 add_disk_fwnode+0x759/0xfc0 block/genhd.c:510
 add_disk include/linux/blkdev.h:758 [inline]
 brd_alloc+0x59c/0x840 drivers/block/brd.c:401
 brd_init+0x126/0x1b0 drivers/block/brd.c:481
 do_one_initcall+0x248/0x930 init/main.c:1257
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888142ba6300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888142ba6380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888142ba6400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888142ba6480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888142ba6500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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