WARNING: kmalloc bug in bpf_prog_array_copy_info

[syzbot]

Hello,

syzbot hit the following crash on bpf-next commit
7928b2cbe55b2a410a0f5c1f154610059c57b1b2 (Sun Feb 11 23:04:29 2018 +0000)
Linux 4.16-rc1

So far this crash happened 362 times on bpf-next.
C reproducer is attached.
syzkaller reproducer is attached.
Raw console output is attached.
compiler: gcc (GCC) 7.1.1 20170620
.config is attached.

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Reported-by: syzbot+cab581...@syzkaller.appspotmail.com
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audit: type=1400 audit(1518458605.853:8): avc: denied { prog_load } for
pid=4110 comm="syzkaller462229"
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=bpf
permissive=1
audit: type=1400 audit(1518458605.881:9): avc: denied { prog_run } for
pid=4110 comm="syzkaller462229"
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=bpf
permissive=1
WARNING: CPU: 1 PID: 4110 at mm/slab_common.c:1012 kmalloc_slab+0x5d/0x70
mm/slab_common.c:1012
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4110 Comm: syzkaller462229 Not tainted 4.16.0-rc1+ #12
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:53
panic+0x1e4/0x41c kernel/panic.c:183
__warn+0x1dc/0x200 kernel/panic.c:547
report_bug+0x211/0x2d0 lib/bug.c:184
fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178
fixup_bug arch/x86/kernel/traps.c:247 [inline]
do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
invalid_op+0x22/0x40 arch/x86/entry/entry_64.S:988
RIP: 0010:kmalloc_slab+0x5d/0x70 mm/slab_common.c:1012
RSP: 0018:ffff8801be09f798 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff10037c13f22 RCX: ffffffff817e12fd
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000fffff8a4
RBP: ffff8801be09f798 R08: ffffed0037c13f26 R09: ffffed0037c13f26
R10: 0000000000000001 R11: ffffed0037c13f26 R12: ffff8801d90d8080
R13: ffff8801be09f930 R14: 00000000014280c0 R15: 000000003ffffe29
__do_kmalloc mm/slab.c:3700 [inline]
__kmalloc+0x25/0x760 mm/slab.c:3714
kmalloc_array include/linux/slab.h:631 [inline]
kcalloc include/linux/slab.h:642 [inline]
bpf_prog_array_copy_to_user+0x98/0x480 kernel/bpf/core.c:1593
bpf_prog_array_copy_info+0x17b/0x1c0 kernel/bpf/core.c:1701
perf_event_query_prog_array+0x196/0x280 kernel/trace/bpf_trace.c:877
_perf_ioctl kernel/events/core.c:4737 [inline]
perf_ioctl+0x3e1/0x1480 kernel/events/core.c:4757
vfs_ioctl fs/ioctl.c:46 [inline]
do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
do_syscall_64+0x282/0x940 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x26/0x9b
RIP: 0033:0x43ff89
RSP: 002b:00007ffd84f05b68 EFLAGS: 00000217 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 000000000043ff89
RDX: 00000000206a8000 RSI: 00000000c008240a RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000217 R12: 00000000004018b0
R13: 0000000000401940 R14: 0000000000000000 R15: 0000000000000000
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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[Daniel Borkmann]

On 02/14/2018 12:59 AM, syzbot wrote:
> Hello,
>
> syzbot hit the following crash on bpf-next commit
> 7928b2cbe55b2a410a0f5c1f154610059c57b1b2 (Sun Feb 11 23:04:29 2018 +0000)
> Linux 4.16-rc1
>
> So far this crash happened 362 times on bpf-next.
> C reproducer is attached.
> syzkaller reproducer is attached.
> Raw console output is attached.
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached.

Will send a fix for this in a bit.

[Daniel Borkmann]

(http://patchwork.ozlabs.org/patch/873373/)

#syz fix: bpf: fix bpf_prog_array_copy_to_user warning from perf event prog query