Message-ID: <CANp29Y4-+Xipt+0wwR+7KWg=c+tbLEM+E8PgvijFiT4cpODbaA@mail.gmail.com>
Date: Sun, 4 May 2025 09:31:10 +0200
From: Aleksandr Nogikh <nogikh@...gle.com>
To: syzbot <syzbot+57ff869c12cb6d89393d@...kaller.appspotmail.com>
Cc: arve@...roid.com, brauner@...nel.org, cmllamas@...gle.com, 
	gregkh@...uxfoundation.org, joel@...lfernandes.org, 
	linux-kernel@...r.kernel.org, maco@...roid.com, surenb@...gle.com, 
	syzkaller-bugs@...glegroups.com, tkjos@...roid.com
Subject: Re: [syzbot] [kernel?] upstream test error: KASAN:
 slab-use-after-free Write in binder_add_device (3)

This was found on an outdated tree. Please ignore.

#syz invalid

On Sun, May 4, 2025 at 3:01 AM syzbot
<syzbot+57ff869c12cb6d89393d@...kaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    29281a76709c Merge tag 'kvmarm-fixes-6.14-2' into kvmarm-m..
> git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git fuzzme
> console output: https://syzkaller.appspot.com/x/log.txt?x=14951774580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=22c3bbf92fcca116
> dashboard link: https://syzkaller.appspot.com/bug?extid=57ff869c12cb6d89393d
> compiler:       Debian clang version 20.1.3 (++20250415083350+2131242240f7-1~exp1~20250415203523.103), Debian LLD 20.1.3
> userspace arch: arm64
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/384ffdcca292/non_bootable_disk-29281a76.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/a94df683c08e/vmlinux-29281a76.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/18ac847cc37c/Image-29281a76.gz.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+57ff869c12cb6d89393d@...kaller.appspotmail.com
>
> ==================================================================
> 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+0xf4/0xf8 drivers/android/binder.c:6932
> Write of size 8 at addr b7f0000014f4e208 by task syz-executor/3305
> Pointer tag: [b7], memory tag: [a6]
>
> CPU: 0 UID: 0 PID: 3305 Comm: syz-executor Not tainted 6.14.0-rc2-syzkaller-g29281a76709c #0
> Hardware name: linux,dummy-virt (DT)
> Call trace:
>  show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C)
>  __dump_stack+0x30/0x40 lib/dump_stack.c:94
>  dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
>  print_address_description+0xac/0x290 mm/kasan/report.c:378
>  print_report+0x84/0xa0 mm/kasan/report.c:489
>  kasan_report+0xb0/0x110 mm/kasan/report.c:602
>  kasan_tag_mismatch+0x28/0x3c mm/kasan/sw_tags.c:175
>  __hwasan_tag_mismatch+0x30/0x60 arch/arm64/lib/kasan_sw_tags.S:55
>  hlist_add_head include/linux/list.h:1026 [inline]
>  binder_add_device+0xf4/0xf8 drivers/android/binder.c:6932
>  binderfs_binder_device_create+0xbfc/0xc28 drivers/android/binderfs.c:210
>  binderfs_fill_super+0xb30/0xe20 drivers/android/binderfs.c:729
>  vfs_get_super fs/super.c:1280 [inline]
>  get_tree_nodev+0xdc/0x1cc fs/super.c:1299
>  binderfs_fs_context_get_tree+0x28/0x38 drivers/android/binderfs.c:749
>  vfs_get_tree+0xc4/0x3cc fs/super.c:1814
>  do_new_mount+0x2a0/0x988 fs/namespace.c:3560
>  path_mount+0x650/0x101c fs/namespace.c:3887
>  do_mount fs/namespace.c:3900 [inline]
>  __do_sys_mount fs/namespace.c:4111 [inline]
>  __se_sys_mount fs/namespace.c:4088 [inline]
>  __arm64_sys_mount+0x36c/0x468 fs/namespace.c:4088
>  __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
>  invoke_syscall+0x90/0x2b4 arch/arm64/kernel/syscall.c:49
>  el0_svc_common+0x180/0x2f4 arch/arm64/kernel/syscall.c:132
>  do_el0_svc+0x58/0x74 arch/arm64/kernel/syscall.c:151
>  el0_svc+0x58/0x134 arch/arm64/kernel/entry-common.c:744
>  el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
>  el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
>
> Allocated by task 3297:
>  kasan_save_stack+0x40/0x6c mm/kasan/common.c:47
>  save_stack_info+0x30/0x138 mm/kasan/tags.c:106
>  kasan_save_alloc_info+0x14/0x20 mm/kasan/tags.c:142
>  poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
>  __kasan_kmalloc+0x8c/0x90 mm/kasan/common.c:394
>  kasan_kmalloc include/linux/kasan.h:260 [inline]
>  __kmalloc_cache_noprof+0x2a0/0x404 mm/slub.c:4325
>  kmalloc_noprof include/linux/slab.h:901 [inline]
>  kzalloc_noprof include/linux/slab.h:1037 [inline]
>  binderfs_binder_device_create+0x1ac/0xc28 drivers/android/binderfs.c:147
>  binderfs_fill_super+0xb30/0xe20 drivers/android/binderfs.c:729
>  vfs_get_super fs/super.c:1280 [inline]
>  get_tree_nodev+0xdc/0x1cc fs/super.c:1299
>  binderfs_fs_context_get_tree+0x28/0x38 drivers/android/binderfs.c:749
>  vfs_get_tree+0xc4/0x3cc fs/super.c:1814
>  do_new_mount+0x2a0/0x988 fs/namespace.c:3560
>  path_mount+0x650/0x101c fs/namespace.c:3887
>  do_mount fs/namespace.c:3900 [inline]
>  __do_sys_mount fs/namespace.c:4111 [inline]
>  __se_sys_mount fs/namespace.c:4088 [inline]
>  __arm64_sys_mount+0x36c/0x468 fs/namespace.c:4088
>  __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
>  invoke_syscall+0x90/0x2b4 arch/arm64/kernel/syscall.c:49
>  el0_svc_common+0x180/0x2f4 arch/arm64/kernel/syscall.c:132
>  do_el0_svc+0x58/0x74 arch/arm64/kernel/syscall.c:151
>  el0_svc+0x58/0x134 arch/arm64/kernel/entry-common.c:744
>  el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
>  el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
>
> Freed by task 3297:
>  kasan_save_stack+0x40/0x6c mm/kasan/common.c:47
>  save_stack_info+0x30/0x138 mm/kasan/tags.c:106
>  kasan_save_free_info+0x18/0x24 mm/kasan/tags.c:147
>  poison_slab_object mm/kasan/common.c:247 [inline]
>  __kasan_slab_free+0x64/0x68 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+0x148/0x44c mm/slub.c:4757
>  binderfs_evict_inode+0x1e8/0x2b8 drivers/android/binderfs.c:278
>  evict+0x4d4/0xbe8 fs/inode.c:796
>  iput_final fs/inode.c:1946 [inline]
>  iput+0x928/0x9e0 fs/inode.c:1972
>  dentry_unlink_inode+0x624/0x660 fs/dcache.c:440
>  __dentry_kill+0x224/0x808 fs/dcache.c:643
>  shrink_kill+0xd4/0x2cc fs/dcache.c:1088
>  shrink_dentry_list+0x420/0x970 fs/dcache.c:1115
>  shrink_dcache_parent+0x80/0x200 fs/dcache.c:-1
>  do_one_tree+0x2c/0x148 fs/dcache.c:1578
>  shrink_dcache_for_umount+0xb0/0x198 fs/dcache.c:1595
>  generic_shutdown_super+0x84/0x424 fs/super.c:620
>  kill_anon_super fs/super.c:1237 [inline]
>  kill_litter_super+0xa4/0xdc fs/super.c:1247
>  binderfs_kill_super+0x50/0xcc drivers/android/binderfs.c:791
>  deactivate_locked_super+0xf0/0x17c fs/super.c:473
>  deactivate_super+0xf4/0x104 fs/super.c:506
>  cleanup_mnt+0x3fc/0x484 fs/namespace.c:1413
>  __cleanup_mnt+0x20/0x30 fs/namespace.c:1420
>  task_work_run+0x1bc/0x254 kernel/task_work.c:227
>  exit_task_work include/linux/task_work.h:40 [inline]
>  do_exit+0x740/0x23b0 kernel/exit.c:938
>  do_group_exit+0x1d4/0x2ac kernel/exit.c:1087
>  get_signal+0x1440/0x1554 kernel/signal.c:3036
>  do_signal+0x23c/0x3ecc arch/arm64/kernel/signal.c:1658
>  do_notify_resume+0x78/0x27c arch/arm64/kernel/entry-common.c:148
>  exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
>  exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
>  el0_svc+0xb0/0x134 arch/arm64/kernel/entry-common.c:745
>  el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
>  el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
>
> The buggy address belongs to the object at fff0000014f4e200
>  which belongs to the cache kmalloc-512 of size 512
> The buggy address is located 8 bytes inside of
>  272-byte region [fff0000014f4e200, fff0000014f4e310)
>
> The buggy address belongs to the physical page:
> page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x54f4e
> anon flags: 0x1ffc00000000000(node=0|zone=0|lastcpupid=0x7ff|kasantag=0x0)
> page_type: f5(slab)
> raw: 01ffc00000000000 7ef000000c801900 0000000000000000 0000000000000001
> raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>  fff0000014f4e000: 29 29 29 29 29 29 29 29 29 29 29 29 29 29 29 29
>  fff0000014f4e100: 29 29 29 29 29 29 29 29 29 29 29 29 29 29 29 29
> >fff0000014f4e200: a6 a6 a6 a6 a6 a6 a6 a6 a6 a6 a6 a6 a6 a6 a6 a6
>                    ^
>  fff0000014f4e300: a6 fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>  fff0000014f4e400: 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35 35
> ==================================================================
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@...glegroups.com.
>
> syzbot will keep track of this issue. See:
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>
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