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Date:      Sun, 12 Apr 2020 12:25:39 -0400
From:      Mark Johnston <markj@freebsd.org>
To:        Peter Holm <pho@freebsd.org>
Cc:        src-committers@freebsd.org, svn-src-user@freebsd.org
Subject:   Re: svn commit: r359820 - user/pho/stress2/misc
Message-ID:  <20200412162539.GA2519@raichu>
In-Reply-To: <202004120559.03C5xKI3099770@repo.freebsd.org>
References:  <202004120559.03C5xKI3099770@repo.freebsd.org>

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On Sun, Apr 12, 2020 at 05:59:20AM +0000, Peter Holm wrote:
> Author: pho
> Date: Sun Apr 12 05:59:20 2020
> New Revision: 359820
> URL: https://svnweb.freebsd.org/changeset/base/359820
> 
> Log:
>   Added more syzkaller reproducers.
> 
> Added:
>   user/pho/stress2/misc/syzkaller5.sh   (contents, props changed)
>   user/pho/stress2/misc/syzkaller6.sh   (contents, props changed)
>   user/pho/stress2/misc/syzkaller7.sh   (contents, props changed)
> [...]
> Added: user/pho/stress2/misc/syzkaller7.sh
> ==============================================================================
> --- /dev/null	00:00:00 1970	(empty, because file is newly added)
> +++ user/pho/stress2/misc/syzkaller7.sh	Sun Apr 12 05:59:20 2020	(r359820)
> @@ -0,0 +1,163 @@
> +#!/bin/sh
> +
> +# panic: Duplicate free of 0xfffff800049ad800 from zone 
> +# 0xfffff800041e82c0(mbuf) slab 0xfffff800049adf90(8)
> +#
> +# KDB: stack backtrace:
> +# db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 
> +# 0xfffffe0016b2c4a0
> +# vpanic() at vpanic+0x1e0/frame 0xfffffe0016b2c500
> +# panic() at panic+0x43/frame 0xfffffe0016b2c560
> +# uma_dbg_free() at uma_dbg_free+0x246/frame 0xfffffe0016b2c5b0
> +# uma_zfree_arg() at uma_zfree_arg+0x1aa/frame 0xfffffe0016b2c640
> +# uipc_ready() at uipc_ready+0x19f/frame 0xfffffe0016b2c690
> +# sendfile_iodone() at sendfile_iodone+0x342/frame 0xfffffe0016b2c6f0
> +# vnode_pager_generic_getpages_done_async() at 
> +# vnode_pager_generic_getpages_done_async+0x4a/frame 0xfffffe0016b2c720
> +# bufdone() at bufdone+0xa1/frame 0xfffffe0016b2c7a0
> +# g_io_deliver() at g_io_deliver+0x35b/frame 0xfffffe0016b2c800
> +# g_io_deliver() at g_io_deliver+0x35b/frame 0xfffffe0016b2c860
> +# g_io_deliver() at g_io_deliver+0x35b/frame 0xfffffe0016b2c8c0
> +# g_disk_done() at g_disk_done+0x179/frame 0xfffffe0016b2c910
> +# dadone() at dadone+0x655/frame 0xfffffe0016b2c9a0
> +# xpt_done_process() at xpt_done_process+0x5b2/frame 0xfffffe0016b2ca00
> +# xpt_done_td() at xpt_done_td+0x175/frame 0xfffffe0016b2ca60
> +# fork_exit() at fork_exit+0xb0/frame 0xfffffe0016b2cab0
> +# fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe0016b2cab0
> +# --- trap 0, rip = 0, rsp = 0, rbp = 0 ---
> +
> +# $FreeBSD$
> +
> +# Not reproduced on r359769

There is a bug in old reproducers that causes them to fail.
Specifically, the call:

  syscall(SYS_mmap, 0x20000000, 0x1000000, 3, 0x1012, -1, 0);

should be

  syscall(SYS_mmap, 0x20000000, 0x1000000, 3, 0x1012, -1, 0ul);

There is some discussion of the problem here:
https://github.com/google/syzkaller/pull/1493

In general, when testing old reproducers, all you need to do is manually
adjust SYS_mmap calls as above.

> +# Fixed by r359779
> +
> +[ `uname -p` = "i386" ] && exit 0
> +
> +. ../default.cfg
> +cat > /tmp/syzkaller7.c <<EOF
> +// https://syzkaller.appspot.com/bug?id=3a27f6d4656356facc22a9329be797ef1143d0ad
> +// autogenerated by syzkaller (https://github.com/google/syzkaller)
> +
> +#define _GNU_SOURCE
> +
> +#include <sys/types.h>
> +
> +#include <pwd.h>
> +#include <signal.h>
> +#include <stdarg.h>
> +#include <stdbool.h>
> +#include <stdint.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/endian.h>
> +#include <sys/syscall.h>
> +#include <sys/wait.h>
> +#include <time.h>
> +#include <unistd.h>
> +
> +static void kill_and_wait(int pid, int* status)
> +{
> +  kill(pid, SIGKILL);
> +  while (waitpid(-1, status, 0) != pid) {
> +  }
> +}
> +
> +static void sleep_ms(uint64_t ms)
> +{
> +  usleep(ms * 1000);
> +}
> +
> +static uint64_t current_time_ms(void)
> +{
> +  struct timespec ts;
> +  if (clock_gettime(CLOCK_MONOTONIC, &ts))
> +    exit(1);
> +  return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
> +}
> +
> +static void execute_one(void);
> +
> +#define WAIT_FLAGS 0
> +
> +static void loop(void)
> +{
> +  int iter;
> +  for (iter = 0;; iter++) {
> +    int pid = fork();
> +    if (pid < 0)
> +      exit(1);
> +    if (pid == 0) {
> +      execute_one();
> +      exit(0);
> +    }
> +    int status = 0;
> +    uint64_t start = current_time_ms();
> +    for (;;) {
> +      if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
> +        break;
> +      sleep_ms(1);
> +      if (current_time_ms() - start < 5 * 1000)
> +        continue;
> +      kill_and_wait(pid, &status);
> +      break;
> +    }
> +  }
> +}
> +
> +uint64_t r[5] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff,
> +                 0xffffffffffffffff, 0xffffffffffffffff};
> +
> +void execute_one(void)
> +{
> +  long res = 0;
> +  memcpy((void*)0x20001180, "./file0\000", 8);
> +  res = syscall(SYS_open, 0x20001180, 0x8240, 0);
> +  if (res != -1)
> +    r[0] = res;
> +  res = syscall(SYS_socketpair, 1, 1, 0, 0x20000100);
> +  if (res != -1) {
> +    r[1] = *(uint32_t*)0x20000100;
> +    r[2] = *(uint32_t*)0x20000104;
> +  }
> +  memcpy((void*)0x20000480, "./file0\000", 8);
> +  res = syscall(SYS_open, 0x20000480, 0x80000000000206, 0);
> +  if (res != -1)
> +    r[3] = res;
> +  res = syscall(SYS_dup, r[3]);
> +  if (res != -1)
> +    r[4] = res;
> +  *(uint64_t*)0x20000100 = 0x200002c0;
> +  memcpy((void*)0x200002c0, "\xdd", 1);
> +  *(uint64_t*)0x20000108 = 1;
> +  syscall(SYS_pwritev, r[4], 0x20000100, 1, 0);
> +  *(uint64_t*)0x20002e80 = 0x20000540;
> +  memcpy((void*)0x20000540, "\x7f", 1);
> +  *(uint64_t*)0x20002e88 = 1;
> +  syscall(SYS_pwritev, r[3], 0x20002e80, 1, 0xbf24);
> +  memcpy((void*)0x200004c0,
> +         "\x89\x88\xaa\x4a\xc3\x95\x23\x77\x54\xee\x66\xf3\x8d\xa4\xae\xf3\x47"
> +         "\x6d\x78\xb7\x1f\xe6\x0d\xb7\x4a\x9f\xb9\xc9\x99\x91\x6c\x98",
> +         32);
> +  syscall(SYS_setsockopt, r[2], 0, 2, 0x200004c0, 0x20);
> +  syscall(SYS_fcntl, r[4], 4, 0x10044);
> +  syscall(SYS_read, r[4], 0x20000000, 0x6d999);
> +  syscall(SYS_sendfile, r[0], r[1], 0, 2);
> +}
> +int main(void)
> +{
> +  syscall(SYS_mmap, 0x20000000, 0x1000000, 3, 0x1012, -1, 0);
> +  loop();
> +  return 0;
> +}
> +EOF
> +mycc -o /tmp/syzkaller7 -Wall -Wextra -O2 /tmp/syzkaller7.c -lpthread ||
> +    exit 1
> +
> +(cd /tmp; ./syzkaller7) &
> +sleep 60
> +pkill -9 syzkaller7
> +wait
> +
> +rm -f /tmp/syzkaller7 /tmp/syzkaller7.c /tmp/syzkaller7.core /tmp/file0
> +exit 0



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