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From:   Martijn Coenen <maco@android.com>
Date:   Wed, 7 Mar 2018 08:52:54 +0100
Message-ID: <CAB0TPYH99OTEd14DfFJFG=ry265D5zkNeBXewKMZ922WDfjuJg@mail.gmail.com>
Subject: Re: KASAN: use-after-free Read in __list_del_entry_valid (3)
To:     syzbot <syzbot+09e05aba06723a94d43d@syzkaller.appspotmail.com>
Cc:     =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= <arve@android.com>,
        "open list:ANDROID DRIVERS" <devel@driverdev.osuosl.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        syzkaller-bugs@googlegroups.com, Todd Kjos <tkjos@android.com>
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On Tue, Mar 6, 2018 at 9:30 AM, syzbot
<syzbot+09e05aba06723a94d43d@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot hit the following crash on upstream commit
> 094b58e1040a44f991d7ab628035e69c4d6b79c9 (Mon Mar 5 19:57:06 2018 +0000)
> Merge tag 'linux-kselftest-4.16-rc5' of
> git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

I'll take a look at this one,

Martijn

>
> Unfortunately, I don't have any reproducer for this crash yet.
> Raw console output is attached.
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached.
> user-space arch: i386
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+09e05aba06723a94d43d@syzkaller.appspotmail.com
> It will help syzbot understand when the bug is fixed. See footer for
> details.
> If you forward the report, please keep this part and the footer.
>
> binder: release 6174:6185 transaction 4 in, still active
> binder: send failed reply for transaction 4 to 6174:6185
> binder: 6194:6198 ERROR: BC_REGISTER_LOOPER called without request
> ==================================================================
> binder: 6198 RLIMIT_NICE not set
> BUG: KASAN: use-after-free in __list_del_entry_valid+0x144/0x150
> lib/list_debug.c:54
> Read of size 8 at addr ffff8801daede810 by task kworker/1:1/24
>
> CPU: 1 PID: 24 Comm: kworker/1:1 Not tainted 4.16.0-rc4+ #252
> binder: BINDER_SET_CONTEXT_MGR already set
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Workqueue: events binder_deferred_func
> Call Trace:
>  __dump_stack lib/dump_stack.c:17 [inline]
>  dump_stack+0x194/0x24d lib/dump_stack.c:53
> binder: 6194:6206 got new transaction with bad transaction stack,
> transaction 9 has target 6194:0
>  print_address_description+0x73/0x250 mm/kasan/report.c:256
>  kasan_report_error mm/kasan/report.c:354 [inline]
>  kasan_report+0x23c/0x360 mm/kasan/report.c:412
>  __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
>  __list_del_entry_valid+0x144/0x150 lib/list_debug.c:54
>  __list_del_entry include/linux/list.h:117 [inline]
>  list_del_init include/linux/list.h:159 [inline]
>  binder_dequeue_work_head_ilocked drivers/android/binder.c:893 [inline]
>  binder_dequeue_work_head drivers/android/binder.c:913 [inline]
>  binder_release_work+0x163/0x490 drivers/android/binder.c:4191
> binder: 6194:6206 transaction failed 29201/-71, size 0-0 line 2875
> binder: 6191:6205 ioctl 40046207 0 returned -16
>  binder_thread_release+0x4d0/0x720 drivers/android/binder.c:4396
>  binder_deferred_release drivers/android/binder.c:4939 [inline]
>  binder_deferred_func+0x4f4/0x1340 drivers/android/binder.c:5022
> binder: BINDER_SET_CONTEXT_MGR already set
> binder: 6200:6207 ioctl 40046207 0 returned -16
> binder: 6191:6208 ERROR: BC_REGISTER_LOOPER called without request
>  process_one_work+0xc47/0x1bb0 kernel/workqueue.c:2113
> binder: 6208 RLIMIT_NICE not set
> binder: 6200:6212 ERROR: BC_REGISTER_LOOPER called without request
> binder: 6212 RLIMIT_NICE not set
> binder: 6191:6213 got new transaction with bad transaction stack,
> transaction 11 has target 6194:0
>  worker_thread+0x223/0x1990 kernel/workqueue.c:2247
> binder: 6191:6213 transaction failed 29201/-71, size 0-0 line 2875
> binder: 6198 RLIMIT_NICE not set
> binder: release 6200:6207 transaction 14 out, still active
> binder: undelivered TRANSACTION_COMPLETE
>  kthread+0x33c/0x400 kernel/kthread.c:238
>  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406
>
> Allocated by task 6185:
>  save_stack+0x43/0xd0 mm/kasan/kasan.c:447
>  set_track mm/kasan/kasan.c:459 [inline]
>  kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552
>  kmem_cache_alloc_trace+0x136/0x740 mm/slab.c:3607
>  kmalloc include/linux/slab.h:512 [inline]
>  kzalloc include/linux/slab.h:701 [inline]
>  binder_transaction+0x13c1/0x81c0 drivers/android/binder.c:2900
>  binder_thread_write+0xb50/0x3840 drivers/android/binder.c:3513
>  binder_ioctl_write_read.isra.38+0x261/0xcb0 drivers/android/binder.c:4451
>  binder_ioctl+0xb72/0x1417 drivers/android/binder.c:4591
>  C_SYSC_ioctl fs/compat_ioctl.c:1461 [inline]
>  compat_SyS_ioctl+0x151/0x2a30 fs/compat_ioctl.c:1407
>  do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
>  do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392
>  entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
>
> Freed by task 24:
>  save_stack+0x43/0xd0 mm/kasan/kasan.c:447
>  set_track mm/kasan/kasan.c:459 [inline]
>  __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
>  kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
>  __cache_free mm/slab.c:3485 [inline]
>  kfree+0xd9/0x260 mm/slab.c:3800
>  binder_free_transaction+0x6a/0x90 drivers/android/binder.c:1966
>  binder_send_failed_reply+0x1c9/0x380 drivers/android/binder.c:2005
>  binder_thread_release+0x4bb/0x720 drivers/android/binder.c:4395
>  binder_deferred_release drivers/android/binder.c:4939 [inline]
>  binder_deferred_func+0x4f4/0x1340 drivers/android/binder.c:5022
>  process_one_work+0xc47/0x1bb0 kernel/workqueue.c:2113
>  worker_thread+0x223/0x1990 kernel/workqueue.c:2247
>  kthread+0x33c/0x400 kernel/kthread.c:238
>  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406
>
> The buggy address belongs to the object at ffff8801daede800
>  which belongs to the cache kmalloc-192 of size 192
> The buggy address is located 16 bytes inside of
>  192-byte region [ffff8801daede800, ffff8801daede8c0)
> The buggy address belongs to the page:
> page:ffffea00076bb780 count:1 mapcount:0 mapping:ffff8801daede000 index:0x0
> flags: 0x2fffc0000000100(slab)
> raw: 02fffc0000000100 ffff8801daede000 0000000000000000 0000000100000010
> raw: ffffea0006e746e0 ffffea0006f0b620 ffff8801dac00040 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>  ffff8801daede700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>  ffff8801daede780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>>
>> ffff8801daede800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>
>                          ^
>  ffff8801daede880: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>  ffff8801daede900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ==================================================================
>
>
> ---
> This bug is generated by a dumb bot. It may contain errors.
> See https://goo.gl/tpsmEJ for details.
> Direct all questions to syzkaller@googlegroups.com.
>
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