linux-user: emulated process reading /proc/self/mem doesn't see guest view of memory map
Host environment
- Operating system: Arch Linux
- OS/kernel version: 5.14.10-arch1-1 #1 SMP PREEMPT Thu, 07 Oct 2021 20:00:23 +0000 x86_64 GNU/Linux
- Architecture: x86_64
- QEMU flavor: qemu-arm
- QEMU version: qemu-arm version 6.1.50 (v6.1.0-1735-gc52d69e7)
- QEMU command line:
(repro is attached 32-bit ARM statically-linked binary, source code below)
qemu-arm ./repro
Emulated/Virtualized environment
- Operating system: N/A
- OS/kernel version: N/A
- Architecture: ARM
Description of problem
QEMU user-mode emulation of a 32-bit guest on a 64-bit host doesn't seem to emulate /proc/self/mem (or /proc/$pid/mem) correctly. Based on the contents of /proc/self/maps, there seems to be some sort of address translation happening that /proc/self/mem doesn't honor.
The following source file:
#include <fcntl.h>
#include <inttypes.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>
static const char string[] = "Hello, world!\n";
static bool copy_to_stdout(const char *path)
{
bool success = false;
int fd = open(path, O_RDONLY);
if (fd < 0) {
perror("open");
return false;
}
char buf[16 * 1024];
while (true) {
ssize_t bytes_read = read(fd, buf, sizeof(buf));
if (bytes_read == 0) {
success = true;
goto out;
} else if (bytes_read < 0) {
perror("read");
goto out;
}
ssize_t bytes_written = 0;
while (bytes_written < bytes_read) {
ssize_t ret = write(STDOUT_FILENO, buf + bytes_written,
bytes_read - bytes_written);
if (ret < 0) {
perror("write");
goto out;
}
bytes_written += ret;
}
}
out:
close(fd);
return success;
}
static bool dump_maps(void)
{
printf("Maps read by self:\n");
fflush(stdout);
if (!copy_to_stdout("/proc/self/maps"))
return false;
printf("\nMaps read by child process:\n");
fflush(stdout);
pid_t pid = fork();
if (pid < 0) {
perror("fork");
return false;
}
if (pid == 0) {
char parent_maps[32];
sprintf(parent_maps, "/proc/%u/maps", (unsigned int)getppid());
if (copy_to_stdout(parent_maps))
_exit(EXIT_SUCCESS);
else
_exit(EXIT_FAILURE);
}
int wstatus;
if (waitpid(pid, &wstatus, 0) < 0 ||
!WIFEXITED(wstatus) || WEXITSTATUS(wstatus) != EXIT_SUCCESS)
return false;
printf("\n");
return true;
}
int main(void)
{
if (!dump_maps())
return EXIT_FAILURE;
int fd = open("/proc/self/mem", O_RDONLY);
if (fd < 0) {
perror("open: /proc/self/mem");
return EXIT_FAILURE;
}
char buf[sizeof(string)];
printf("Reading %zu bytes from %p (%" PRIuPTR ") to %p of PID %u\n",
sizeof(buf), string, (uintptr_t)string, buf,
(unsigned int)getpid());
fflush(stdout);
if (pread(fd, buf, sizeof(buf), (uintptr_t)string) < 0) {
perror("pread: /proc/self/mem");
return EXIT_FAILURE;
}
if (memcmp(buf, string, sizeof(buf)) != 0) {
fprintf(stderr, "buffer doesn't match\n");
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}when compiled for 32-bit ARM produces the following output:
Maps read by self:
10000-7c000 r-xp 00000000 00:19 8275924 /home/osandov/repro
7c000-8b000 ---p 00000000 00:00 0
8b000-8c000 r--p 0006b000 00:19 8275924 /home/osandov/repro
8c000-8d000 rw-p 0006c000 00:19 8275924 /home/osandov/repro
8d000-b0000 rw-p 00000000 00:00 0
3ffff000-40000000 r-xp 00000000 00:00 0
40000000-40001000 ---p 00000000 00:00 0
40001000-40801000 rw-p 00000000 00:00 0 [stack]
Maps read by child process:
00010000-00020000 ---p 00000000 00:00 0
00020000-0008c000 r--p 00000000 00:19 8275924 /home/osandov/repro
0008c000-0009b000 ---p 00000000 00:00 0
0009b000-0009c000 r--p 0006b000 00:19 8275924 /home/osandov/repro
0009c000-0009d000 rw-p 0006c000 00:19 8275924 /home/osandov/repro
0009d000-000c0000 rw-p 00000000 00:00 0
000c0000-4000f000 ---p 00000000 00:00 0
4000f000-40010000 r--p 00000000 00:00 0
40010000-40011000 ---p 00000000 00:00 0
40011000-40811000 rw-p 00000000 00:00 0
40811000-100000000 ---p 00000000 00:00 0
100000000-100001000 r--p 00000000 00:00 0
5636dd7a2000-5636dd8a4000 r--p 00000000 00:19 8270028 /home/osandov/repos/qemu/build/qemu-arm
5636dd8a4000-5636ddb13000 r-xp 00102000 00:19 8270028 /home/osandov/repos/qemu/build/qemu-arm
5636ddb13000-5636ddf69000 r--p 00371000 00:19 8270028 /home/osandov/repos/qemu/build/qemu-arm
5636ddf6a000-5636ddfe7000 r--p 007c7000 00:19 8270028 /home/osandov/repos/qemu/build/qemu-arm
5636ddfe7000-5636ddff3000 rw-p 00844000 00:19 8270028 /home/osandov/repos/qemu/build/qemu-arm
5636ddff3000-5636de010000 rw-p 00000000 00:00 0
5636df67b000-5636df80c000 rw-p 00000000 00:00 0 [heap]
7f3008000000-7f300ffff000 rwxp 00000000 00:00 0
7f300ffff000-7f3010000000 ---p 00000000 00:00 0
7f3010000000-7f3010021000 rw-p 00000000 00:00 0
7f3010021000-7f3014000000 ---p 00000000 00:00 0
7f3017119000-7f301719a000 rw-p 00000000 00:00 0
7f301719a000-7f301719b000 ---p 00000000 00:00 0
7f301719b000-7f30179a1000 rw-p 00000000 00:00 0
7f30179a1000-7f30179a3000 r--p 00000000 00:19 3660771 /usr/lib/libffi.so.8.1.0
7f30179a3000-7f30179a9000 r-xp 00002000 00:19 3660771 /usr/lib/libffi.so.8.1.0
7f30179a9000-7f30179ab000 r--p 00008000 00:19 3660771 /usr/lib/libffi.so.8.1.0
7f30179ab000-7f30179ac000 r--p 00009000 00:19 3660771 /usr/lib/libffi.so.8.1.0
7f30179ac000-7f30179ad000 rw-p 0000a000 00:19 3660771 /usr/lib/libffi.so.8.1.0
7f30179ad000-7f30179be000 r--p 00000000 00:19 1476709 /usr/lib/libgmp.so.10.4.1
7f30179be000-7f3017a32000 r-xp 00011000 00:19 1476709 /usr/lib/libgmp.so.10.4.1
7f3017a32000-7f3017a49000 r--p 00085000 00:19 1476709 /usr/lib/libgmp.so.10.4.1
7f3017a49000-7f3017a4a000 ---p 0009c000 00:19 1476709 /usr/lib/libgmp.so.10.4.1
7f3017a4a000-7f3017a4c000 r--p 0009c000 00:19 1476709 /usr/lib/libgmp.so.10.4.1
7f3017a4c000-7f3017a4d000 rw-p 0009e000 00:19 1476709 /usr/lib/libgmp.so.10.4.1
7f3017a4d000-7f3017a56000 r--p 00000000 00:19 2871144 /usr/lib/libhogweed.so.6.4
7f3017a56000-7f3017a69000 r-xp 00009000 00:19 2871144 /usr/lib/libhogweed.so.6.4
7f3017a69000-7f3017a93000 r--p 0001c000 00:19 2871144 /usr/lib/libhogweed.so.6.4
7f3017a93000-7f3017a95000 r--p 00045000 00:19 2871144 /usr/lib/libhogweed.so.6.4
7f3017a95000-7f3017a96000 rw-p 00047000 00:19 2871144 /usr/lib/libhogweed.so.6.4
7f3017a96000-7f3017a98000 rw-p 00000000 00:00 0
7f3017a98000-7f3017aa4000 r--p 00000000 00:19 2871147 /usr/lib/libnettle.so.8.4
7f3017aa4000-7f3017ac5000 r-xp 0000c000 00:19 2871147 /usr/lib/libnettle.so.8.4
7f3017ac5000-7f3017adb000 r--p 0002d000 00:19 2871147 /usr/lib/libnettle.so.8.4
7f3017adb000-7f3017adc000 ---p 00043000 00:19 2871147 /usr/lib/libnettle.so.8.4
7f3017adc000-7f3017ade000 r--p 00043000 00:19 2871147 /usr/lib/libnettle.so.8.4
7f3017ade000-7f3017adf000 rw-p 00045000 00:19 2871147 /usr/lib/libnettle.so.8.4
7f3017adf000-7f3017ae2000 r--p 00000000 00:19 2550729 /usr/lib/libtasn1.so.6.6.1
7f3017ae2000-7f3017aee000 r-xp 00003000 00:19 2550729 /usr/lib/libtasn1.so.6.6.1
7f3017aee000-7f3017af2000 r--p 0000f000 00:19 2550729 /usr/lib/libtasn1.so.6.6.1
7f3017af2000-7f3017af3000 ---p 00013000 00:19 2550729 /usr/lib/libtasn1.so.6.6.1
7f3017af3000-7f3017af4000 r--p 00013000 00:19 2550729 /usr/lib/libtasn1.so.6.6.1
7f3017af4000-7f3017af5000 rw-p 00014000 00:19 2550729 /usr/lib/libtasn1.so.6.6.1
7f3017af5000-7f3017b06000 r--p 00000000 00:19 937656 /usr/lib/libunistring.so.2.1.0
7f3017b06000-7f3017b3b000 r-xp 00011000 00:19 937656 /usr/lib/libunistring.so.2.1.0
7f3017b3b000-7f3017c72000 r--p 00046000 00:19 937656 /usr/lib/libunistring.so.2.1.0
7f3017c72000-7f3017c76000 r--p 0017c000 00:19 937656 /usr/lib/libunistring.so.2.1.0
7f3017c76000-7f3017c77000 rw-p 00180000 00:19 937656 /usr/lib/libunistring.so.2.1.0
7f3017c77000-7f3017c79000 r--p 00000000 00:19 3212638 /usr/lib/libidn2.so.0.3.7
7f3017c79000-7f3017c7d000 r-xp 00002000 00:19 3212638 /usr/lib/libidn2.so.0.3.7
7f3017c7d000-7f3017c97000 r--p 00006000 00:19 3212638 /usr/lib/libidn2.so.0.3.7
7f3017c97000-7f3017c98000 r--p 0001f000 00:19 3212638 /usr/lib/libidn2.so.0.3.7
7f3017c98000-7f3017c99000 rw-p 00020000 00:19 3212638 /usr/lib/libidn2.so.0.3.7
7f3017c99000-7f3017cc2000 r--p 00000000 00:19 3663986 /usr/lib/libp11-kit.so.0.3.0
7f3017cc2000-7f3017d60000 r-xp 00029000 00:19 3663986 /usr/lib/libp11-kit.so.0.3.0
7f3017d60000-7f3017dba000 r--p 000c7000 00:19 3663986 /usr/lib/libp11-kit.so.0.3.0
7f3017dba000-7f3017dc4000 r--p 00120000 00:19 3663986 /usr/lib/libp11-kit.so.0.3.0
7f3017dc4000-7f3017dce000 rw-p 0012a000 00:19 3663986 /usr/lib/libp11-kit.so.0.3.0
7f3017dce000-7f3017dd0000 r--p 00000000 00:19 2549813 /usr/lib/libdl-2.33.so
7f3017dd0000-7f3017dd2000 r-xp 00002000 00:19 2549813 /usr/lib/libdl-2.33.so
7f3017dd2000-7f3017dd3000 r--p 00004000 00:19 2549813 /usr/lib/libdl-2.33.so
7f3017dd3000-7f3017dd4000 r--p 00004000 00:19 2549813 /usr/lib/libdl-2.33.so
7f3017dd4000-7f3017dd5000 rw-p 00005000 00:19 2549813 /usr/lib/libdl-2.33.so
7f3017dd5000-7f3017dd7000 rw-p 00000000 00:00 0
7f3017dd7000-7f3017dd9000 r--p 00000000 00:19 3020974 /usr/lib/libpcre.so.1.2.13
7f3017dd9000-7f3017e2f000 r-xp 00002000 00:19 3020974 /usr/lib/libpcre.so.1.2.13
7f3017e2f000-7f3017e4c000 r--p 00058000 00:19 3020974 /usr/lib/libpcre.so.1.2.13
7f3017e4c000-7f3017e4d000 r--p 00074000 00:19 3020974 /usr/lib/libpcre.so.1.2.13
7f3017e4d000-7f3017e4e000 rw-p 00075000 00:19 3020974 /usr/lib/libpcre.so.1.2.13
7f3017e4e000-7f3017e74000 r--p 00000000 00:19 2549806 /usr/lib/libc-2.33.so
7f3017e74000-7f3017fbf000 r-xp 00026000 00:19 2549806 /usr/lib/libc-2.33.so
7f3017fbf000-7f301800b000 r--p 00171000 00:19 2549806 /usr/lib/libc-2.33.so
7f301800b000-7f301800e000 r--p 001bc000 00:19 2549806 /usr/lib/libc-2.33.so
7f301800e000-7f3018011000 rw-p 001bf000 00:19 2549806 /usr/lib/libc-2.33.so
7f3018011000-7f301801a000 rw-p 00000000 00:00 0
7f301801a000-7f3018021000 r--p 00000000 00:19 2549847 /usr/lib/libpthread-2.33.so
7f3018021000-7f3018030000 r-xp 00007000 00:19 2549847 /usr/lib/libpthread-2.33.so
7f3018030000-7f3018034000 r--p 00016000 00:19 2549847 /usr/lib/libpthread-2.33.so
7f3018034000-7f3018035000 ---p 0001a000 00:19 2549847 /usr/lib/libpthread-2.33.so
7f3018035000-7f3018036000 r--p 0001a000 00:19 2549847 /usr/lib/libpthread-2.33.so
7f3018036000-7f3018037000 rw-p 0001b000 00:19 2549847 /usr/lib/libpthread-2.33.so
7f3018037000-7f301803b000 rw-p 00000000 00:00 0
7f301803b000-7f301803e000 r--p 00000000 00:19 2550528 /usr/lib/libgcc_s.so.1
7f301803e000-7f3018050000 r-xp 00003000 00:19 2550528 /usr/lib/libgcc_s.so.1
7f3018050000-7f3018053000 r--p 00015000 00:19 2550528 /usr/lib/libgcc_s.so.1
7f3018053000-7f3018054000 ---p 00018000 00:19 2550528 /usr/lib/libgcc_s.so.1
7f3018054000-7f3018055000 r--p 00018000 00:19 2550528 /usr/lib/libgcc_s.so.1
7f3018055000-7f3018056000 rw-p 00019000 00:19 2550528 /usr/lib/libgcc_s.so.1
7f3018056000-7f3018065000 r--p 00000000 00:19 2549819 /usr/lib/libm-2.33.so
7f3018065000-7f30180ff000 r-xp 0000f000 00:19 2549819 /usr/lib/libm-2.33.so
7f30180ff000-7f3018197000 r--p 000a9000 00:19 2549819 /usr/lib/libm-2.33.so
7f3018197000-7f3018198000 ---p 00141000 00:19 2549819 /usr/lib/libm-2.33.so
7f3018198000-7f3018199000 r--p 00141000 00:19 2549819 /usr/lib/libm-2.33.so
7f3018199000-7f301819a000 rw-p 00142000 00:19 2549819 /usr/lib/libm-2.33.so
7f301819a000-7f3018233000 r--p 00000000 00:19 2550558 /usr/lib/libstdc++.so.6.0.29
7f3018233000-7f3018333000 r-xp 00099000 00:19 2550558 /usr/lib/libstdc++.so.6.0.29
7f3018333000-7f301839f000 r--p 00199000 00:19 2550558 /usr/lib/libstdc++.so.6.0.29
7f301839f000-7f30183ac000 r--p 00204000 00:19 2550558 /usr/lib/libstdc++.so.6.0.29
7f30183ac000-7f30183ad000 rw-p 00211000 00:19 2550558 /usr/lib/libstdc++.so.6.0.29
7f30183ad000-7f30183b2000 rw-p 00000000 00:00 0
7f30183b2000-7f30183e6000 r--p 00000000 00:19 2907924 /usr/lib/libgnutls.so.30.30.0
7f30183e6000-7f3018508000 r-xp 00034000 00:19 2907924 /usr/lib/libgnutls.so.30.30.0
7f3018508000-7f301859d000 r--p 00156000 00:19 2907924 /usr/lib/libgnutls.so.30.30.0
7f301859d000-7f301859e000 ---p 001eb000 00:19 2907924 /usr/lib/libgnutls.so.30.30.0
7f301859e000-7f30185af000 r--p 001eb000 00:19 2907924 /usr/lib/libgnutls.so.30.30.0
7f30185af000-7f30185b1000 rw-p 001fc000 00:19 2907924 /usr/lib/libgnutls.so.30.30.0
7f30185b1000-7f30185b3000 rw-p 00000000 00:00 0
7f30185b3000-7f30185b5000 r--p 00000000 00:19 3662215 /usr/lib/libgmodule-2.0.so.0.7000.0
7f30185b5000-7f30185b7000 r-xp 00002000 00:19 3662215 /usr/lib/libgmodule-2.0.so.0.7000.0
7f30185b7000-7f30185b8000 r--p 00004000 00:19 3662215 /usr/lib/libgmodule-2.0.so.0.7000.0
7f30185b8000-7f30185b9000 r--p 00004000 00:19 3662215 /usr/lib/libgmodule-2.0.so.0.7000.0
7f30185b9000-7f30185ba000 rw-p 00005000 00:19 3662215 /usr/lib/libgmodule-2.0.so.0.7000.0
7f30185ba000-7f30185d7000 r--p 00000000 00:19 3662212 /usr/lib/libglib-2.0.so.0.7000.0
7f30185d7000-7f3018664000 r-xp 0001d000 00:19 3662212 /usr/lib/libglib-2.0.so.0.7000.0
7f3018664000-7f30186ec000 r--p 000aa000 00:19 3662212 /usr/lib/libglib-2.0.so.0.7000.0
7f30186ec000-7f30186ed000 ---p 00132000 00:19 3662212 /usr/lib/libglib-2.0.so.0.7000.0
7f30186ed000-7f30186ee000 r--p 00132000 00:19 3662212 /usr/lib/libglib-2.0.so.0.7000.0
7f30186ee000-7f30186ef000 rw-p 00133000 00:19 3662212 /usr/lib/libglib-2.0.so.0.7000.0
7f30186ef000-7f30186f0000 rw-p 00000000 00:00 0
7f30186f0000-7f30186f2000 r--p 00000000 00:19 3440204 /usr/lib/liburing.so.2.1.0
7f30186f2000-7f30186f4000 r-xp 00002000 00:19 3440204 /usr/lib/liburing.so.2.1.0
7f30186f4000-7f30186f5000 r--p 00004000 00:19 3440204 /usr/lib/liburing.so.2.1.0
7f30186f5000-7f30186f6000 r--p 00004000 00:19 3440204 /usr/lib/liburing.so.2.1.0
7f30186f6000-7f30186f7000 rw-p 00005000 00:19 3440204 /usr/lib/liburing.so.2.1.0
7f30186f7000-7f30186fa000 r--p 00000000 00:19 2549855 /usr/lib/librt-2.33.so
7f30186fa000-7f30186fe000 r-xp 00003000 00:19 2549855 /usr/lib/librt-2.33.so
7f30186fe000-7f3018700000 r--p 00007000 00:19 2549855 /usr/lib/librt-2.33.so
7f3018700000-7f3018701000 r--p 00008000 00:19 2549855 /usr/lib/librt-2.33.so
7f3018701000-7f3018702000 rw-p 00009000 00:19 2549855 /usr/lib/librt-2.33.so
7f3018702000-7f3018705000 r--p 00000000 00:19 15838 /usr/lib/libz.so.1.2.11
7f3018705000-7f3018713000 r-xp 00003000 00:19 15838 /usr/lib/libz.so.1.2.11
7f3018713000-7f3018719000 r--p 00011000 00:19 15838 /usr/lib/libz.so.1.2.11
7f3018719000-7f301871a000 ---p 00017000 00:19 15838 /usr/lib/libz.so.1.2.11
7f301871a000-7f301871b000 r--p 00017000 00:19 15838 /usr/lib/libz.so.1.2.11
7f301871b000-7f301871c000 rw-p 00018000 00:19 15838 /usr/lib/libz.so.1.2.11
7f301871c000-7f301871e000 rw-p 00000000 00:00 0
7f301871e000-7f301871f000 r--p 00000000 00:19 2549795 /usr/lib/ld-2.33.so
7f301871f000-7f3018743000 r-xp 00001000 00:19 2549795 /usr/lib/ld-2.33.so
7f3018743000-7f301874c000 r--p 00025000 00:19 2549795 /usr/lib/ld-2.33.so
7f301874c000-7f301874e000 r--p 0002d000 00:19 2549795 /usr/lib/ld-2.33.so
7f301874e000-7f3018750000 rw-p 0002f000 00:19 2549795 /usr/lib/ld-2.33.so
7ffc5c8f6000-7ffc5c917000 rw-p 00000000 00:00 0 [stack]
7ffc5c935000-7ffc5c939000 r--p 00000000 00:00 0 [vvar]
7ffc5c939000-7ffc5c93b000 r-xp 00000000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 --xp 00000000 00:00 0 [vsyscall]
Reading 15 bytes from 0x6377c (407420) to 0x40800638 of PID 278331
buffer doesn't matchThe program is trying to read from 0x6377c, which according to the emulated maps is in this mapping:
10000-7c000 r-xp 00000000 00:19 8275924 /home/osandov/reprobut on the host, it's mapped differently:
00020000-0008c000 r--p 00000000 00:19 8275924 /home/osandov/reproWhen using qemu-arm-static (version 6.1.0 (Debian 1:6.1+dfsg-6)) via binfmt_misc, I also saw a case where the address isn't mapped in the host at all:
Maps read by self:
10000-7c000 r-xp 00000000 00:19 8275924 /home/osandov/repro
7c000-8b000 ---p 00000000 00:00 0
8b000-8c000 r--p 0006b000 00:19 8275924 /home/osandov/repro
8c000-8d000 rw-p 0006c000 00:19 8275924 /home/osandov/repro
8d000-b0000 rw-p 00000000 00:00 0
40000000-40001000 ---p 00000000 00:00 0
40001000-40801000 rw-p 00000000 00:00 0 [stack]
Maps read by child process:
00400000-00401000 r--p 00000000 00:19 297 /usr/bin/qemu-arm-static
00401000-00769000 r-xp 00001000 00:19 297 /usr/bin/qemu-arm-static
00769000-00abe000 r--p 00369000 00:19 297 /usr/bin/qemu-arm-static
00abe000-00c58000 r--p 006bd000 00:19 297 /usr/bin/qemu-arm-static
00c58000-00cd3000 rw-p 00857000 00:19 297 /usr/bin/qemu-arm-static
00cd3000-00cf7000 rw-p 00000000 00:00 0
0253c000-0268e000 rw-p 00000000 00:00 0 [heap]
42645000-42655000 ---p 00000000 00:00 0
42655000-426c1000 r--p 00000000 00:19 8275924 /home/osandov/repro
426c1000-426d0000 ---p 00000000 00:00 0
426d0000-426d1000 r--p 0006b000 00:19 8275924 /home/osandov/repro
426d1000-426d2000 rw-p 0006c000 00:19 8275924 /home/osandov/repro
426d2000-426f5000 rw-p 00000000 00:00 0
426f5000-82645000 ---p 00000000 00:00 0
82645000-82646000 ---p 00000000 00:00 0
82646000-82e46000 rw-p 00000000 00:00 0
82e46000-142635000 ---p 00000000 00:00 0
142635000-142636000 r--p 00000000 00:00 0
7f5584000000-7f558bfff000 rwxp 00000000 00:00 0
7f558bfff000-7f558c000000 ---p 00000000 00:00 0
7f558c000000-7f558c021000 rw-p 00000000 00:00 0
7f558c021000-7f5590000000 ---p 00000000 00:00 0
7f55929b5000-7f5592a36000 rw-p 00000000 00:00 0
7f5592a36000-7f5592a37000 ---p 00000000 00:00 0
7f5592a37000-7f5593237000 rw-p 00000000 00:00 0
7ffc4971a000-7ffc4973b000 rw-p 00000000 00:00 0 [stack]
7ffc497fa000-7ffc497fe000 r--p 00000000 00:00 0 [vvar]
7ffc497fe000-7ffc49800000 r-xp 00000000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 --xp 00000000 00:00 0 [vsyscall]
Reading 15 bytes from 0x6377c (407420) to 0x40800648 of PID 278443
pread: /proc/self/mem: Input/output errorSteps to reproduce
- Download statically-linked ARM reproducer.
- Run
qemu-arm ./repro.
Additional information
I encountered this when trying out a CI system that uses QEMU user-mode emulation for 32-bit ARM builds. My project is a debugger that uses /proc/self/mem, and a test case tripped over this. See https://github.com/osandov/drgn/pull/126.
This also seems to happen with a i386 guest, but not with an aarch64 guest, so I'm assuming that it's a 32-bit guest issue.
Edited by Alex Bennée