WARNING in bpf_check

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 671dffa7de7b Merge branch 'bpf-bpftool-improved-prog-load'
git tree: bpf-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1550b562400000
kernel config: https://syzkaller.appspot.com/x/.config?x=a501a01deaf0fe9
dashboard link: https://syzkaller.appspot.com/bug?extid=7d427828b2ea6e592804
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+7d4278...@syzkaller.appspotmail.com

RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000013
R13: 00000000004bbbc2 R14: 00000000004c8e28 R15: 0000000000000037
------------[ cut here ]------------
verifier bug. No program starts at insn 3
WARNING: CPU: 0 PID: 12586 at kernel/bpf/verifier.c:1613
get_callee_stack_depth kernel/bpf/verifier.c:1612 [inline]
WARNING: CPU: 0 PID: 12586 at kernel/bpf/verifier.c:1613 fixup_call_args
kernel/bpf/verifier.c:5587 [inline]
WARNING: CPU: 0 PID: 12586 at kernel/bpf/verifier.c:1613
bpf_check+0x5239/0x5e60 kernel/bpf/verifier.c:5952
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 12586 Comm: syz-executor0 Not tainted 4.18.0-rc3+ #49
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+0x1c9/0x2b4 lib/dump_stack.c:113
panic+0x238/0x4e7 kernel/panic.c:184
__warn.cold.8+0x163/0x1ba kernel/panic.c:536
report_bug+0x252/0x2d0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992
RIP: 0010:get_callee_stack_depth kernel/bpf/verifier.c:1612 [inline]
RIP: 0010:fixup_call_args kernel/bpf/verifier.c:5587 [inline]
RIP: 0010:bpf_check+0x5239/0x5e60 kernel/bpf/verifier.c:5952
Code: ff 48 89 df e8 28 08 2e 00 e9 d8 d7 ff ff e8 6e 2f f0 ff 8b 74 24 58
48 c7 c7 20 8d ef 87 c6 05 d5 f1 0d 08 01 e8 37 52 bb ff <0f> 0b 48 8b 54
24 08 b8 ff ff 37 00 48 c1 e0 2a 48 c1 ea 03 0f b6
RSP: 0018:ffff88019745f980 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc90003eec000
RDX: 0000000000040000 RSI: ffffffff81631851 RDI: ffff88019745f658
RBP: ffff88019745fb30 R08: ffff880197666100 R09: fffffbfff11f1220
R10: fffffbfff11f1220 R11: ffffffff88f89103 R12: dffffc0000000000
R13: ffffc90001ace040 R14: 00000000fffffffe R15: ffff8801b0b7e800
bpf_prog_load+0x1141/0x1c90 kernel/bpf/syscall.c:1352
__do_sys_bpf kernel/bpf/syscall.c:2305 [inline]
__se_sys_bpf kernel/bpf/syscall.c:2267 [inline]
__x64_sys_bpf+0x36c/0x510 kernel/bpf/syscall.c:2267
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455e29
Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f28af3e8c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f28af3e96d4 RCX: 0000000000455e29
RDX: 0000000000000048 RSI: 0000000020000000 RDI: 0000000000000005
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000013
R13: 00000000004bbbc2 R14: 00000000004c8e28 R15: 0000000000000037
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug 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 syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
syzbot.

[Dmitry Vyukov]

Reproducer is below. It seems to be related to the kmalloc failure in
jit_subprogs():


[ 140.990644] FAULT_INJECTION: forcing a failure.
[ 140.990644] name failslab, interval 1, probability 0, space 0, times 0
[ 140.994740] CPU: 3 PID: 4072 Comm: a.out Not tainted 4.18.0-rc4+ #51
[ 140.997070] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.10.2-1 04/01/2014
[ 141.000046] Call Trace:
[ 141.001025] __dump_stack lib/dump_stack.c:77 [inline]
[ 141.001025] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
[ 141.001714] ? dump_stack_print_info.cold.2+0x52/0x52 lib/dump_stack.c:60
[ 141.002637] ? kernel_text_address+0x79/0xf0 kernel/extable.c:152
[ 141.003423] fail_dump lib/fault-inject.c:51 [inline]
[ 141.003423] should_fail.cold.4+0xa/0x1a lib/fault-inject.c:149
[ 141.004145] ? fault_create_debugfs_attr+0x1f0/0x1f0 lib/fault-inject.c:249
[ 141.005056] ? save_stack+0xa9/0xd0 mm/kasan/kasan.c:454
[ 141.005694] ? save_stack+0x43/0xd0 mm/kasan/kasan.c:448
[ 141.006352] ? graph_lock+0x170/0x170 arch/x86/include/asm/paravirt.h:674
[ 141.007021] ? lock_downgrade+0x8f0/0x8f0 kernel/locking/lockdep.c:3658
[ 141.007736] ? __lock_is_held+0xb5/0x140 kernel/locking/lockdep.c:3744
[ 141.008441] ? trace_hardirqs_off+0xd/0x10 kernel/locking/lockdep.c:2932
[ 141.009190] ? rcu_note_context_switch+0x730/0x730
include/linux/compiler.h:188
[ 141.010052] __should_failslab+0x124/0x180 mm/failslab.c:32
[ 141.010789] should_failslab+0x9/0x14 mm/slab_common.c:1557
[ 141.011450] slab_pre_alloc_hook mm/slab.h:423 [inline]
[ 141.011450] slab_alloc mm/slab.c:3378 [inline]
[ 141.011450] __do_kmalloc mm/slab.c:3716 [inline]
[ 141.011450] __kmalloc+0x2c8/0x760 mm/slab.c:3727
[ 141.012070] ? find_subprog+0xbb/0x100 kernel/bpf/verifier.c:778
[ 141.012773] ? find_good_pkt_pointers+0x630/0x630 kernel/bpf/verifier.c:3422
[ 141.013632] ? kmalloc_array include/linux/slab.h:635 [inline]
[ 141.013632] ? kcalloc include/linux/slab.h:646 [inline]
[ 141.013632] ? jit_subprogs kernel/bpf/verifier.c:5451 [inline]
[ 141.013632] ? fixup_call_args kernel/bpf/verifier.c:5578 [inline]
[ 141.013632] ? bpf_check+0x3947/0x5e60 kernel/bpf/verifier.c:5952
[ 141.014309] ? trace_hardirqs_on+0xd/0x10 kernel/locking/lockdep.c:2894
[ 141.015019] kmalloc_array include/linux/slab.h:635 [inline]
[ 141.015019] kcalloc include/linux/slab.h:646 [inline]
[ 141.015019] jit_subprogs kernel/bpf/verifier.c:5451 [inline]
[ 141.015019] fixup_call_args kernel/bpf/verifier.c:5578 [inline]
[ 141.015019] bpf_check+0x3947/0x5e60 kernel/bpf/verifier.c:5952
[ 141.015668] ? pvclock_read_flags+0x160/0x160
arch/x86/include/asm/pvclock.h:35
[ 141.016453] ? fixup_bpf_calls+0x1fb0/0x1fb0 kernel/bpf/verifier.c:5677
[ 141.017224] ? ktime_get_with_offset+0x32e/0x4b0
kernel/time/timekeeping.c:788
[ 141.018046] ? ktime_get+0x440/0x440 kernel/time/timekeeping.c:751
[ 141.018693] ? memset+0x31/0x40 mm/kasan/kasan.c:287
[ 141.019264] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 kernel/kcov.c:174
[ 141.020180] ? bpf_obj_name_cpy+0x17c/0x1c0 kernel/bpf/syscall.c:427
[ 141.020890] bpf_prog_load+0x1141/0x1c90 kernel/bpf/syscall.c:1352
[ 141.021555] ? bpf_prog_new_fd+0x60/0x60 kernel/bpf/syscall.c:1099
[ 141.022220] ? lock_downgrade+0x8f0/0x8f0 kernel/locking/lockdep.c:3658
[ 141.022903] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 kernel/kcov.c:195
[ 141.023842] __do_sys_bpf kernel/bpf/syscall.c:2305 [inline]
[ 141.023842] __se_sys_bpf kernel/bpf/syscall.c:2267 [inline]
[ 141.023842] __x64_sys_bpf+0x36c/0x510 kernel/bpf/syscall.c:2267
[ 141.024529] ? bpf_prog_get+0x20/0x20 kernel/bpf/syscall.c:1197
[ 141.025214] ? do_syscall_64+0x9a/0x820 arch/x86/entry/common.c:277
[ 141.025905] do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
[ 141.026583] ? syscall_return_slowpath+0x5e0/0x5e0
arch/x86/entry/common.c:255
[ 141.027435] ? prepare_exit_to_usermode arch/x86/entry/common.c:211 [inline]
[ 141.027435] ? syscall_return_slowpath+0x31d/0x5e0
arch/x86/entry/common.c:268
[ 141.028293] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe
[ 141.029237] ? trace_hardirqs_off_thunk+0x1a/0x1c
[ 141.030089] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 141.030998] RIP: 0033:0x44a949
[ 141.031559] Code: e8 2c aa 01 00 48 83 c4 18 c3 0f 1f 80 00 00 00
00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24
08 0f 05 <48> 3d 01 f0 ff ff 0f 83 0b 0c fc ff c3 66 2e 0f 1f 84 00 00
00 00
[ 141.035037] RSP: 002b:00007fe7874b0d88 EFLAGS: 00000206 ORIG_RAX:
0000000000000141
[ 141.036347] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000044a949
[ 141.037590] RDX: 0000000000000048 RSI: 0000000020000000 RDI: 0000000000000005
[ 141.038813] RBP: 00007fe7874b0da0 R08: 0000000000000002 R09: 0000000000000000
[ 141.040069] R10: 0000000000000001 R11: 0000000000000206 R12: 0000000000000000
[ 141.041302] R13: 00007ffe20cc628f R14: 00007fe7874b1700 R15: 0000000000000000
[ 141.042804] ------------[ cut here ]------------
[ 141.043668] verifier bug. No program starts at insn 3
[ 141.044648] ARNING: CPU: 3 PID: 4072 at kernel/bpf/verifier.c:1613
get_callee_stack_depth kernel/bpf/verifier.c:1612 [inline]
[ 141.044648] ARNING: CPU: 3 PID: 4072 at kernel/bpf/verifier.c:1613
fixup_call_args kernel/bpf/verifier.c:5587 [inline]
[ 141.044648] ARNING: CPU: 3 PID: 4072 at kernel/bpf/verifier.c:1613
bpf_check+0x525e/0x5e60 kernel/bpf/verifier.c:5952
[ 141.046103]
[ 141.047355] CPU: 3 PID: 4072 Comm: a.out Not tainted 4.18.0-rc4+ #51
[ 141.048446] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.10.2-1 04/01/2014
[ 141.049877] Call Trace:
[ 141.050324] __dump_stack lib/dump_stack.c:77 [inline]
[ 141.050324] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
[ 141.050950] ? dump_stack_print_info.cold.2+0x52/0x52 lib/dump_stack.c:60
[ 141.051837] panic+0x238/0x4e7 kernel/panic.c:184
[ 141.052386] ? add_taint.cold.5+0x16/0x16 kernel/panic.c:385
[ 141.053101] ? __warn.cold.8+0x148/0x1ba kernel/panic.c:537
[ 141.053814] ? __warn.cold.8+0x117/0x1ba kernel/panic.c:530
[ 141.054506] ? get_callee_stack_depth kernel/bpf/verifier.c:1612 [inline]
[ 141.054506] ? fixup_call_args kernel/bpf/verifier.c:5587 [inline]
[ 141.054506] ? bpf_check+0x525e/0x5e60 kernel/bpf/verifier.c:5952
[ 141.055163] __warn.cold.8+0x163/0x1ba kernel/panic.c:538
[ 141.055820] ? get_callee_stack_depth kernel/bpf/verifier.c:1612 [inline]
[ 141.055820] ? fixup_call_args kernel/bpf/verifier.c:5587 [inline]
[ 141.055820] ? bpf_check+0x525e/0x5e60 kernel/bpf/verifier.c:5952
[ 141.056478] report_bug+0x252/0x2d0 lib/bug.c:186
[ 141.057106] fixup_bug arch/x86/kernel/traps.c:178 [inline]
[ 141.057106] do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
[ 141.057764] ? graph_lock+0x170/0x170 arch/x86/include/asm/paravirt.h:674
[ 141.058402] ? math_error+0x3e0/0x3e0 arch/x86/kernel/traps.c:844
[ 141.059058] ? vprintk_default+0x28/0x30 kernel/printk/printk.c:1991
[ 141.059748] ? vprintk_func+0x81/0xe7 kernel/printk/printk_safe.c:383
[ 141.060395] ? printk+0xa7/0xcf kernel/printk/printk.c:2024
[ 141.060975] ? trace_hardirqs_off_thunk+0x1a/0x1c
[ 141.061800] do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
[ 141.062434] invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992
[ 141.063026] RIP: 0010:get_callee_stack_depth
kernel/bpf/verifier.c:1612 [inline]
[ 141.063026] RIP: 0010:fixup_call_args kernel/bpf/verifier.c:5587 [inline]
[ 141.063026] RIP: 0010:bpf_check+0x525e/0x5e60 kernel/bpf/verifier.c:5952
[ 141.063795] Code: ff 48 89 df e8 a3 0e 2e 00 e9 7a f2 ff ff e8 b9
30 f0 ff 8b 74 24 58 48 c7 c7 a0 6b b0 87 c6 05 db c9 f3 07 01 e8 a2
41 bb ff <0f> 0b 48 8b 54 24 08 b8 ff ff 37 00 48 c1 e0 2a 48 c1 ea 03
0f b6
[ 141.067166] RSP: 0018:ffff880067b5f980 EFLAGS: 00010286
[ 141.068060] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[ 141.069281] RDX: 0000000000000000 RSI: ffffffff81633d81 RDI: 0000000000000001
[ 141.070478] RBP: ffff880067b5fb30 R08: ffff880062faa340 R09: ffffed000d8f4fc0
[ 141.071687] R10: ffffed000d8f4fc0 R11: ffff88006c7a7e07 R12: dffffc0000000000
[ 141.072912] R13: ffffc90000b68040 R14: 00000000fffffffe R15: ffff8800602e2280
[ 141.074135] ? vprintk_func+0x81/0xe7 kernel/printk/printk_safe.c:383
[ 141.074745] ? pvclock_read_flags+0x160/0x160
arch/x86/include/asm/pvclock.h:35
[ 141.075466] ? fixup_bpf_calls+0x1fb0/0x1fb0 kernel/bpf/verifier.c:5677
[ 141.076167] ? ktime_get_with_offset+0x32e/0x4b0
kernel/time/timekeeping.c:788
[ 141.076928] ? ktime_get+0x440/0x440 kernel/time/timekeeping.c:751
[ 141.077531] ? memset+0x31/0x40 mm/kasan/kasan.c:287
[ 141.078063] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 kernel/kcov.c:174
[ 141.078945] ? bpf_obj_name_cpy+0x17c/0x1c0 kernel/bpf/syscall.c:427
[ 141.079695] bpf_prog_load+0x1141/0x1c90 kernel/bpf/syscall.c:1352
[ 141.080358] ? bpf_prog_new_fd+0x60/0x60 kernel/bpf/syscall.c:1099
[ 141.081018] ? lock_downgrade+0x8f0/0x8f0 kernel/locking/lockdep.c:3658
[ 141.081688] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 kernel/kcov.c:195
[ 141.082576] __do_sys_bpf kernel/bpf/syscall.c:2305 [inline]
[ 141.082576] __se_sys_bpf kernel/bpf/syscall.c:2267 [inline]
[ 141.082576] __x64_sys_bpf+0x36c/0x510 kernel/bpf/syscall.c:2267
[ 141.083217] ? bpf_prog_get+0x20/0x20 kernel/bpf/syscall.c:1197
[ 141.083829] ? do_syscall_64+0x9a/0x820 arch/x86/entry/common.c:277
[ 141.084466] do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
[ 141.085125] ? syscall_return_slowpath+0x5e0/0x5e0
arch/x86/entry/common.c:255
[ 141.085945] ? prepare_exit_to_usermode arch/x86/entry/common.c:211 [inline]
[ 141.085945] ? syscall_return_slowpath+0x31d/0x5e0
arch/x86/entry/common.c:268
[ 141.086764] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe
[ 141.087653] ? trace_hardirqs_off_thunk+0x1a/0x1c
[ 141.088462] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 141.089331] RIP: 0033:0x44a949
[ 141.089858] Code: e8 2c aa 01 00 48 83 c4 18 c3 0f 1f 80 00 00 00
00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24
08 0f 05 <48> 3d 01 f0 ff ff 0f 83 0b 0c fc ff c3 66 2e 0f 1f 84 00 00
00 00
[ 141.093216] RSP: 002b:00007fe7874b0d88 EFLAGS: 00000206 ORIG_RAX:
0000000000000141
[ 141.094510] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000044a949
[ 141.095712] RDX: 0000000000000048 RSI: 0000000020000000 RDI: 0000000000000005
[ 141.096924] RBP: 00007fe7874b0da0 R08: 0000000000000002 R09: 0000000000000000
[ 141.098124] R10: 0000000000000001 R11: 0000000000000206 R12: 0000000000000000
[ 141.099314] R13: 00007ffe20cc628f R14: 00007fe7874b1700 R15: 0000000000000000
[ 141.100989] Kernel Offset: disabled
[ 141.101637] Rebooting in 86400 seconds..




// autogenerated by syzkaller (http://github.com/google/syzkaller)
#define _GNU_SOURCE
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/futex.h>
#include <pthread.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>

__attribute__((noreturn)) static void doexit(int status)
{
volatile unsigned i;
syscall(__NR_exit_group, status);
for (i = 0;; i++) {
}
}
#include <errno.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>

const int kFailStatus = 67;
const int kRetryStatus = 69;

static void exitf(const char* msg, ...)
{
int e = errno;
va_list args;
va_start(args, msg);
vfprintf(stderr, msg, args);
va_end(args);
fprintf(stderr, " (errno %d)\n", e);
doexit(kRetryStatus);
}

static bool write_file(const char* file, const char* what, ...)
{
char buf[1024];
va_list args;
va_start(args, what);
vsnprintf(buf, sizeof(buf), what, args);
va_end(args);
buf[sizeof(buf) - 1] = 0;
int len = strlen(buf);

int fd = open(file, O_WRONLY | O_CLOEXEC);
if (fd == -1)
return false;
if (write(fd, buf, len) != len) {
int err = errno;
close(fd);
errno = err;
return false;
}
close(fd);
return true;
}

static int inject_fault(int nth)
{
int fd;
char buf[16];

fd = open("/proc/thread-self/fail-nth", O_RDWR);
if (fd == -1)
exitf("failed to open /proc/thread-self/fail-nth");
sprintf(buf, "%d", nth + 1);
if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf))
exitf("failed to write /proc/thread-self/fail-nth");
return fd;
}

struct thread_t {
int created, running, call;
pthread_t th;
};

static struct thread_t threads[16];
static void execute_call(int call);
static int running;

static void* thr(void* arg)
{
struct thread_t* th = (struct thread_t*)arg;
for (;;) {
while (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE))
syscall(SYS_futex, &th->running, FUTEX_WAIT, 0, 0);
execute_call(th->call);
__atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
__atomic_store_n(&th->running, 0, __ATOMIC_RELEASE);
syscall(SYS_futex, &th->running, FUTEX_WAKE);
}
return 0;
}

static void execute(int num_calls)
{
int call, thread;
running = 0;
for (call = 0; call < num_calls; call++) {
for (thread = 0; thread < sizeof(threads) / sizeof(threads[0]); thread++) {
struct thread_t* th = &threads[thread];
if (!th->created) {
th->created = 1;
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setstacksize(&attr, 128 << 10);
pthread_create(&th->th, &attr, thr, th);
}
if (!__atomic_load_n(&th->running, __ATOMIC_ACQUIRE)) {
th->call = call;
__atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
__atomic_store_n(&th->running, 1, __ATOMIC_RELEASE);
syscall(SYS_futex, &th->running, FUTEX_WAKE);
struct timespec ts;
ts.tv_sec = 0;
ts.tv_nsec = 20 * 1000 * 1000;
syscall(SYS_futex, &th->running, FUTEX_WAIT, 1, &ts);
if (__atomic_load_n(&running, __ATOMIC_RELAXED))
usleep((call == num_calls - 1) ? 10000 : 1000);
break;
}
}
}
}

#ifndef __NR_bpf
#define __NR_bpf 321
#endif

void execute_call(int call)
{
switch (call) {
case 0:
*(uint32_t*)0x20000000 = 1;
*(uint32_t*)0x20000004 = 0xa;
*(uint64_t*)0x20000008 = 0x20001000;
memcpy((void*)0x20001000,
"\xbf\x16\x00\x00\x00\x00\x00\x00\x85\x10\x00\x00\x05\x00\x00\x00"
"\x54\x00\x00\x00\x00\x00\x00\x00\xbf\x61\x00\x00\x00\x00\x00\x00"
"\x85\x10\x00\x00\x02\x00\x00\x00\xbf\x01\x00\x00\x00\x00\x00\x00"
"\x95\x00\x00\x00\x00\x00\x00\x00\x15\x01\x00\x00\x00\x00\x00\x00"
"\xb7\x00\x00\x00\x00\x00\x00\x00\x95\x00\x00\x00\x00\x00\x00\x00",
80);
*(uint64_t*)0x20000010 = 0x20000100;
memcpy((void*)0x20000100, "GPL", 4);
*(uint32_t*)0x20000018 = 0;
*(uint32_t*)0x2000001c = 0;
*(uint64_t*)0x20000020 = 0;
*(uint32_t*)0x20000028 = 0;
*(uint32_t*)0x2000002c = 0;
*(uint8_t*)0x20000030 = 0;
*(uint8_t*)0x20000031 = 0;
*(uint8_t*)0x20000032 = 0;
*(uint8_t*)0x20000033 = 0;
*(uint8_t*)0x20000034 = 0;
*(uint8_t*)0x20000035 = 0;
*(uint8_t*)0x20000036 = 0;
*(uint8_t*)0x20000037 = 0;
*(uint8_t*)0x20000038 = 0;
*(uint8_t*)0x20000039 = 0;
*(uint8_t*)0x2000003a = 0;
*(uint8_t*)0x2000003b = 0;
*(uint8_t*)0x2000003c = 0;
*(uint8_t*)0x2000003d = 0;
*(uint8_t*)0x2000003e = 0;
*(uint8_t*)0x2000003f = 0;
*(uint32_t*)0x20000040 = 0;
*(uint32_t*)0x20000044 = 0;
write_file("/sys/kernel/debug/failslab/ignore-gfp-wait", "N");
write_file("/sys/kernel/debug/fail_futex/ignore-private", "N");
inject_fault(55);
syscall(__NR_bpf, 5, 0x20000000, 0x48);
break;
}
}

void loop()
{
execute(1);
}

int main()
{
write_file("/sys/kernel/debug/failslab/ignore-gfp-wait", "N");
write_file("/sys/kernel/debug/fail_futex/ignore-private", "N");
inject_fault(55);
syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
loop();
return 0;
}

[Daniel Borkmann]

On 07/12/2018 09:51 AM, Dmitry Vyukov wrote:
> On Thu, Jul 12, 2018 at 9:41 AM, syzbot

[...]

> Reproducer is below. It seems to be related to the kmalloc failure in
> jit_subprogs():

Thanks a lot Dmitry! Already looking into it.

[Daniel Borkmann]

On 07/12/2018 09:51 AM, Dmitry Vyukov wrote:

> On Thu, Jul 12, 2018 at 9:41 AM, syzbot
> <syzbot+7d4278...@syzkaller.appspotmail.com> wrote:
>> Hello,
>>
>> syzbot found the following crash on:
>>
>> HEAD commit: 671dffa7de7b Merge branch 'bpf-bpftool-improved-prog-load'
>> git tree: bpf-next
>> console output: https://syzkaller.appspot.com/x/log.txt?x=1550b562400000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=a501a01deaf0fe9
>> dashboard link: https://syzkaller.appspot.com/bug?extid=7d427828b2ea6e592804
>> compiler: gcc (GCC) 8.0.1 20180413 (experimental)

#syz fix: bpf: don't leave partial mangled prog in jit_subprogs error path