kernel BUG at drivers/android/binder_alloc.c:LINE! (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: dfb686ce BACKPORT: security: Implement Clang's stack initi..
git tree: android-4.14
console output: https://syzkaller.appspot.com/x/log.txt?x=149efa32a00000
kernel config: https://syzkaller.appspot.com/x/.config?x=af826045c37f9ba4
dashboard link: https://syzkaller.appspot.com/bug?extid=e19d7cad89dfe9546a61
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1756a0c9a00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=111e82faa00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e19d7c...@syzkaller.appspotmail.com

random: sshd: uninitialized urandom read (32 bytes read)
audit: type=1400 audit(1560811836.695:7): avc: denied { map } for
pid=1804 comm="syz-executor336" path="/root/syz-executor336234600"
dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
------------[ cut here ]------------
audit: type=1400 audit(1560811836.695:8): avc: denied { map } for
pid=1804 comm="syz-executor336" path="/dev/binder0" dev="devtmpfs" ino=5442
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=system_u:object_r:device_t:s0 tclass=chr_file permissive=1
kernel BUG at drivers/android/binder_alloc.c:1128!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
audit: type=1400 audit(1560811836.695:9): avc: denied { set_context_mgr }
for pid=1804 comm="syz-executor336"
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=binder
permissive=1
Modules linked in:
CPU: 0 PID: 1804 Comm: syz-executor336 Not tainted 4.14.127+ #8
task: (ptrval) task.stack: (ptrval)
RIP: 0010:binder_alloc_do_buffer_copy+0xc7/0x500
drivers/android/binder_alloc.c:1128
RSP: 0018:ffff8881cf4a7550 EFLAGS: 00010297
audit: type=1400 audit(1560811836.695:10): avc: denied { call } for
pid=1804 comm="syz-executor336"
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=binder
permissive=1
RAX: ffff8881d0f20000 RBX: 0000000020001000 RCX: 00000000000000a8
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8881d25f1458
RBP: 0000000000000078 R08: ffff8881cf4a7608 R09: 0000000000000008
R10: ffffed1039e94f1a R11: ffff8881cf4a78d7 R12: ffff8881cff05498
R13: 0000000000000008 R14: 00000000000000a8 R15: ffff8881cf4a7608
FS: 0000000001a61940(0000) GS:ffff8881db800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056252e0af0f0 CR3: 00000001d691e004 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
binder_validate_ptr+0xad/0x190 drivers/android/binder.c:2315
binder_transaction+0x1edf/0x5700 drivers/android/binder.c:3423
audit: type=1400 audit(1560811836.695:11): avc: denied { transfer } for
pid=1804 comm="syz-executor336"
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=binder
permissive=1
Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 0d 04 00 00 48 8b
6d 58 48 29 dd e8 33 14 0c ff 49 39 ed 76 07 e8 29 14 0c ff <0f> 0b e8 22
14 0c ff 4c 29 ed 49 39 ee 77 ec e8 15 14 0c ff 41
RIP: binder_alloc_do_buffer_copy+0xc7/0x500
drivers/android/binder_alloc.c:1128 RSP: ffff8881cf4a7550
---[ end trace 1d84e715307b7948 ]---


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