KASAN: slab-out-of-bounds Write in process_preds

[syzbot]

Hello,

syzbot hit the following crash on upstream commit
b284d4d5a6785f8cd07eda2646a95782373cd01e (Tue Apr 10 19:25:30 2018 +0000)
Merge tag 'ceph-for-4.17-rc1' of git://github.com/ceph/ceph-client
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=5702a7e6d4a13b3accd5

So far this crash happened 4 times on upstream.
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=6364313065357312
syzkaller reproducer:
https://syzkaller.appspot.com/x/repro.syz?id=4775648954417152
Raw console output:
https://syzkaller.appspot.com/x/log.txt?id=6353070183153664
Kernel config:
https://syzkaller.appspot.com/x/.config?id=-1223000601505858474
compiler: gcc (GCC) 8.0.1 20180301 (experimental)

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+5702a7...@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.

==================================================================
BUG: KASAN: slab-out-of-bounds in predicate_parse
kernel/trace/trace_events_filter.c:557 [inline]
BUG: KASAN: slab-out-of-bounds in process_preds+0x1958/0x19b0
kernel/trace/trace_events_filter.c:1505
Write of size 4 at addr ffff8801ceecdef0 by task syzkaller992239/4513

CPU: 0 PID: 4513 Comm: syzkaller992239 Not tainted 4.16.0+ #17
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1b9/0x294 lib/dump_stack.c:113
print_address_description+0x6c/0x20b mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412
__asan_report_store4_noabort+0x17/0x20 mm/kasan/report.c:437
predicate_parse kernel/trace/trace_events_filter.c:557 [inline]
process_preds+0x1958/0x19b0 kernel/trace/trace_events_filter.c:1505
create_filter+0x1a8/0x370 kernel/trace/trace_events_filter.c:1714
ftrace_profile_set_filter+0x109/0x2b0
kernel/trace/trace_events_filter.c:2042
perf_event_set_filter+0x248/0x1230 kernel/events/core.c:9064
_perf_ioctl+0x84c/0x1650 kernel/events/core.c:5056
perf_ioctl+0x59/0x80 kernel/events/core.c:5107
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1cf/0x1650 fs/ioctl.c:684
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
SYSC_ioctl fs/ioctl.c:708 [inline]
SyS_ioctl+0x24/0x30 fs/ioctl.c:706
do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x43fdb9
RSP: 002b:00007ffc7afb3e88 EFLAGS: 00000213 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fdb9
RDX: 0000000020000040 RSI: 0000000040082406 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000213 R12: 00000000004016e0
R13: 0000000000401770 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 1:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620
kmalloc include/linux/slab.h:512 [inline]
call_modprobe kernel/kmod.c:80 [inline]
__request_module+0x386/0xcdd kernel/kmod.c:171
adfdrv_init+0x1b/0x5f drivers/crypto/qat/qat_dh895xcc/adf_drv.c:315
do_one_initcall+0x127/0x913 init/main.c:880
do_initcall_level init/main.c:948 [inline]
do_initcalls init/main.c:956 [inline]
do_basic_setup init/main.c:974 [inline]
kernel_init_freeable+0x49b/0x58e init/main.c:1124
kernel_init+0x11/0x1b3 init/main.c:1050
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411

Freed by task 1:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kfree+0xd9/0x260 mm/slab.c:3813
free_modprobe_argv+0x74/0xa0 kernel/kmod.c:67
call_usermodehelper_freeinfo kernel/umh.c:42 [inline]
call_usermodehelper_exec+0x274/0x4f0 kernel/umh.c:458
call_modprobe kernel/kmod.c:99 [inline]
__request_module+0x4ba/0xcdd kernel/kmod.c:171
adfdrv_init+0x1b/0x5f drivers/crypto/qat/qat_dh895xcc/adf_drv.c:315
do_one_initcall+0x127/0x913 init/main.c:880
do_initcall_level init/main.c:948 [inline]
do_initcalls init/main.c:956 [inline]
do_basic_setup init/main.c:974 [inline]
kernel_init_freeable+0x49b/0x58e init/main.c:1124
kernel_init+0x11/0x1b3 init/main.c:1050
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411

The buggy address belongs to the object at ffff8801ceecde80
which belongs to the cache kmalloc-64 of size 64
The buggy address is located 48 bytes to the right of
64-byte region [ffff8801ceecde80, ffff8801ceecdec0)
The buggy address belongs to the page:
page:ffffea00073bb340 count:1 mapcount:0 mapping:ffff8801ceecd000 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801ceecd000 0000000000000000 0000000100000020
raw: ffffea0007392ba0 ffffea0007509220 ffff8801dac00340 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8801ceecdd80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff8801ceecde00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
> ffff8801ceecde80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
^
ffff8801ceecdf00: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
ffff8801ceecdf80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


---
This bug is generated by a dumb bot. It may contain errors.
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[Dmitry Vyukov]

On Wed, Apr 11, 2018 at 2:02 PM, syzbot
<syzbot+5702a7...@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot hit the following crash on upstream commit
> b284d4d5a6785f8cd07eda2646a95782373cd01e (Tue Apr 10 19:25:30 2018 +0000)
> Merge tag 'ceph-for-4.17-rc1' of git://github.com/ceph/ceph-client
> syzbot dashboard link:
> https://syzkaller.appspot.com/bug?extid=5702a7e6d4a13b3accd5
>
> So far this crash happened 4 times on upstream.
> C reproducer: https://syzkaller.appspot.com/x/repro.c?id=6364313065357312
> syzkaller reproducer:
> https://syzkaller.appspot.com/x/repro.syz?id=4775648954417152
> Raw console output:
> https://syzkaller.appspot.com/x/log.txt?id=6353070183153664
> Kernel config:
> https://syzkaller.appspot.com/x/.config?id=-1223000601505858474
> compiler: gcc (GCC) 8.0.1 20180301 (experimental)
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+5702a7...@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.

This was bisected to:

commit 80765597bc587feae8dbc8ce97a0f32e12a6e625
Author: Steven Rostedt (VMware) <ros...@goodmis.org>
Date: Fri Mar 9 13:19:28 2018 -0500

tracing: Rewrite filter logic to be simpler and faster

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[Steven Rostedt]

On Thu, 10 May 2018 07:14:26 +0200
Dmitry Vyukov <dvy...@google.com> wrote:

> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > Reported-by: syzbot+5702a7...@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.
>
>
> This was bisected to:
>
> commit 80765597bc587feae8dbc8ce97a0f32e12a6e625
> Author: Steven Rostedt (VMware) <ros...@goodmis.org>
> Date: Fri Mar 9 13:19:28 2018 -0500
>
> tracing: Rewrite filter logic to be simpler and faster

I could have told you that without the bisect ;-)

I'll try to get some time to look into this.

-- Steve

[Dmitry Vyukov]

Well, it was a good candidate for testing of automatic bisection process ;)
It seems that it has found the right one, which is good.

[Dmitry Vyukov]

It seems this was lost on kernel mailing lists, then re-reported after 2 months:
https://bugzilla.kernel.org/show_bug.cgi?id=200019
and then fixed.

Since the fixing commit does not contain syzbot tag, need to tell it
about the fix manually:

#syz fix: tracing: Check for no filter when processing event filters

[Steven Rostedt]

On Thu, 23 Aug 2018 07:13:13 -0700
Dmitry Vyukov <dvy...@google.com> wrote:

> On Thu, May 10, 2018 at 7:23 AM, Steven Rostedt <ros...@goodmis.org> wrote:
> > On Thu, 10 May 2018 07:14:26 +0200
> > Dmitry Vyukov <dvy...@google.com> wrote:
> >
> >> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> >> > Reported-by: syzbot+5702a7...@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.
> >>
> >>
> >> This was bisected to:
> >>
> >> commit 80765597bc587feae8dbc8ce97a0f32e12a6e625
> >> Author: Steven Rostedt (VMware) <ros...@goodmis.org>
> >> Date: Fri Mar 9 13:19:28 2018 -0500
> >>
> >> tracing: Rewrite filter logic to be simpler and faster
> >
> > I could have told you that without the bisect ;-)
> >
> > I'll try to get some time to look into this.
>
>
> It seems this was lost on kernel mailing lists, then re-reported after 2 months:
> https://bugzilla.kernel.org/show_bug.cgi?id=200019
> and then fixed.

Yeah, that time was quite busy for me. I guess I failed to get time to
look into it when it was first reported :-(

>
> Since the fixing commit does not contain syzbot tag, need to tell it
> about the fix manually:
>
> #syz fix: tracing: Check for no filter when processing event filters

Sorry about that. Thanks,

-- Steve

[Dmitry Vyukov]

Hi Steven,

No personal criticism meant. I guess this is an inevitable consequence
of the current kernel development process and tooling. Reports and
patches get lots on a regular basis. In some subsystems we don't hear
from maintainers at all. That's one of the things we wanted to solve
with the syzbot dashboard: no thing get lost ever:
https://syzkaller.appspot.com/#upstream
But the other side of the medal is that bug report statues need to be
maintained.