Re: m68k 54418 fails to execute user space

[Michael Schmitz <schmitzmic@gmail.com>]

Jean-Michel,

Am 28.06.2024 um 23:25 schrieb Jean-Michel Hautbois:
>>
>> No heap in this second call. Can you print mm->start_brk and mm->brk
>> please?
>>
>> The process memory layout is a little unusual (I would have expected
>> the binary to be mapped before the dynamic libraries, not after). Is
>> that expected on Coldfire, Greg?
>>
>
> I did the test, and called ls twice to see what differs:
> bash-5.2# ls -l > /dev/null
> load_elf_binary: Dump memory for ls (31):
> mmap: start_brk: 700ca000, brk: 700ca000
> mmap: 60000000-6001e000 r-xp 00000000 00:00 178 /lib/ld.so.1
> mmap: 6001e000-60022000 rw-p 0001c000 00:00 178 /lib/ld.so.1
> mmap: 70000000-700c2000 r-xp 00000000 00:00 28 /bin/busybox
> mmap: 700c2000-700ca000 rw-p 000c0000 00:00 28 /bin/busybox
> mmap: bfa48000-bfa6a000 rw-p bffde000 00:00 0 [stack]
> do_exit: Dump memory for ls (31):
> mmap: start_brk: 700ca000, brk: 700ec000

ls managed to allocate heap space OK ...

> mmap: 60000000-6001e000 r-xp 00000000 00:00 178 /lib/ld.so.1
> mmap: 6001e000-60020000 r--p 0001c000 00:00 178 /lib/ld.so.1
> mmap: 60020000-60022000 rw-p 0001e000 00:00 178 /lib/ld.so.1
> mmap: 60022000-6002c000 r-xp 00000000 00:00 193 /lib/libresolv.so.2
> mmap: 6002c000-6002e000 r--p 00008000 00:00 193 /lib/libresolv.so.2
> mmap: 6002e000-60030000 rw-p 0000a000 00:00 193 /lib/libresolv.so.2
> mmap: 60030000-60032000 rw-p 60030000 00:00 0
> mmap: 60032000-6015a000 r-xp 00000000 00:00 185 /lib/libc.so.6
> mmap: 6015a000-6015c000 r--p 00126000 00:00 185 /lib/libc.so.6
> mmap: 6015c000-60160000 rw-p 00128000 00:00 185 /lib/libc.so.6
> mmap: 60160000-6016e000 rw-p 60160000 00:00 0
> mmap: 70000000-700c2000 r-xp 00000000 00:00 28 /bin/busybox
> mmap: 700c2000-700c4000 r--p 000c0000 00:00 28 /bin/busybox
> mmap: 700c4000-700ca000 rw-p 000c2000 00:00 28 /bin/busybox
> mmap: 700ca000-700ec000 rwxp 700ca000 00:00 0 [heap]
> mmap: bfa48000-bfa6a000 rw-p bffde000 00:00 0 [stack]
> bash-5.2# ls -l > /dev/null
> load_elf_binary: Dump memory for ls (33):
> mmap: start_brk: 700ca000, brk: 700ca000
> mmap: 60000000-6001e000 r-xp 00000000 00:00 178 /lib/ld.so.1
> mmap: 6001e000-60022000 rw-p 0001c000 00:00 178 /lib/ld.so.1
> mmap: 70000000-700c2000 r-xp 00000000 00:00 28 /bin/busybox
> mmap: 700c2000-700ca000 rw-p 000c0000 00:00 28 /bin/busybox
> mmap: bf894000-bf8b6000 rw-p bffde000 00:00 0 [stack]
> do_exit: Dump memory for ls (33):
> mmap: start_brk: 700ca000, brk: 700ca000

No heap space allocated here. I would have expected that to cause an 
error message from libc ...

Can you print a brief meminfo summary such as found in fs/proc/meminfo.c 
(total, free, available, buffer and cached for starters)?

Cheers,

	Michael


> mmap: 60000000-6001e000 r-xp 00000000 00:00 178 /lib/ld.so.1
> mmap: 6001e000-60020000 r--p 0001c000 00:00 178 /lib/ld.so.1
> mmap: 60020000-60022000 rw-p 0001e000 00:00 178 /lib/ld.so.1
> mmap: 60022000-6002c000 r-xp 00000000 00:00 193 /lib/libresolv.so.2
> mmap: 6002c000-6002e000 r--p 00008000 00:00 193 /lib/libresolv.so.2
> mmap: 6002e000-60030000 rw-p 0000a000 00:00 193 /lib/libresolv.so.2
> mmap: 60030000-60032000 rw-p 60030000 00:00 0
> mmap: 60032000-6015a000 r-xp 00000000 00:00 185 /lib/libc.so.6
> mmap: 6015a000-6015c000 r--p 00126000 00:00 185 /lib/libc.so.6
> mmap: 6015c000-60160000 rw-p 00128000 00:00 185 /lib/libc.so.6
> mmap: 60160000-6016e000 rw-p 60160000 00:00 0
> mmap: 70000000-700c2000 r-xp 00000000 00:00 28 /bin/busybox
> mmap: 700c2000-700c4000 r--p 000c0000 00:00 28 /bin/busybox
> mmap: 700c4000-700ca000 rw-p 000c2000 00:00 28 /bin/busybox
> mmap: bf894000-bf8b6000 rw-p bffde000 00:00 0 [stack]
>
> The second time, there seems to be no heap...
>
> JM
>
>> Cheers,
>>
>>      Michael
>>
>>
>>> mmap: bfb5a000-bfb7c000 rw-p bffde000 00:00 0 [stack]
>>>
>>> The first call generates the "ls" output, not the second one.
>>> The helper looks like:
>>> diff --git a/mm/mmap.c b/mm/mmap.c
>>> index 83b4682ec85c..14d861e9cba2 100644
>>> --- a/mm/mmap.c
>>> +++ b/mm/mmap.c
>>> @@ -76,6 +76,87 @@ int mmap_rnd_compat_bits __read_mostly =
>>> CONFIG_ARCH_MMAP_RND_COMPAT_BITS;
>>>  static bool ignore_rlimit_data;
>>>  core_param(ignore_rlimit_data, ignore_rlimit_data, bool, 0644);
>>>
>>> +int dump_memory_map(struct task_struct *task)
>>> +{
>>> +    struct mm_struct *mm = task->mm;
>>> +    struct vm_area_struct *vma;
>>> +    struct file *file;
>>> +    struct path *path;
>>> +    char *buf;
>>> +    char *pathname;
>>> +
>>> +       if (!mm) {
>>> +               return -ENOMEM;
>>> +       }
>>> +
>>> +       MA_STATE(mas, &mm->mm_mt, 0, -1);
>>> +    // Acquire the read lock for mmap_lock
>>> +    down_read(&mm->mmap_lock);
>>> +       mas_lock(&mas);
>>> +       for (vma = mas_find(&mas, ULONG_MAX); vma; vma = mas_find(&mas,
>>> ULONG_MAX)) {
>>> +               char perms[5] = "---p"; // Default permissions
>>> +               // Set permissions based on vm_flags
>>> +               if (vma->vm_flags & VM_READ) perms[0] = 'r';
>>> +               if (vma->vm_flags & VM_WRITE) perms[1] = 'w';
>>> +               if (vma->vm_flags & VM_EXEC) perms[2] = 'x';
>>> +               if (vma->vm_flags & VM_MAYSHARE) perms[3] = 's';
>>> +
>>> +               if (vma->vm_file) { // If there's an associated file
>>> +                       buf = (char *)__get_free_page(GFP_KERNEL);
>>> +                       if (!buf) {
>>> +                               continue; // Handle memory allocation
>>> failure
>>> +                       }
>>> +
>>> +                       file = vma->vm_file;
>>> +                       path = &file->f_path;
>>> +                       pathname = d_path(path, buf, PAGE_SIZE);
>>> +                       if (IS_ERR(pathname)) {
>>> +                               pathname = NULL;
>>> +                       }
>>> +
>>> +                       // Print memory area information with file path
>>> +                       pr_info("%08lx-%08lx %s %08lx %02x:%02x %lu
>>> %s\n",
>>> +                               vma->vm_start, vma->vm_end,
>>> +                               perms,
>>> +                               vma->vm_pgoff << PAGE_SHIFT,
>>> +                               MAJOR(file_inode(file)->i_rdev),
>>> +                               MINOR(file_inode(file)->i_rdev),
>>> +                               file_inode(file)->i_ino,
>>> +                               pathname ? pathname : "");
>>> +
>>> +                       free_page((unsigned long)buf);
>>> +               } else {
>>> +                       char *special_area_name = NULL;
>>> +
>>> +                       // Check for heap
>>> +                       if (vma->vm_end > mm->start_brk && vma->vm_start
>>> < mm->brk) {
>>> +                               special_area_name = "[heap]";
>>> +                       }
>>> +                       // Check for stack
>>> +                       else if (vma->vm_start <= mm->start_stack &&
>>> vma->vm_end >= mm->start_stack) {
>>> +                               special_area_name = "[stack]";
>>> +                       }
>>> +                       // Check for vdso
>>> +                       else if (vma->vm_flags & VM_EXEC &&
>>> vma->vm_flags & VM_READ && !vma->vm_file) {
>>> +                               special_area_name = "[vdso]";
>>> +                       }
>>> +
>>> +                       // Print memory area information without file
>>> path
>>> +                       pr_info("%08lx-%08lx %s %08lx 00:00 0 %s\n",
>>> +                               vma->vm_start, vma->vm_end,
>>> +                               perms,
>>> +                               vma->vm_pgoff << PAGE_SHIFT,
>>> +                               special_area_name ? special_area_name :
>>> "    ");
>>> +               }
>>> +       }
>>> +       mas_unlock(&mas);
>>> +    // Release the read lock for mmap_lock
>>> +    up_read(&mm->mmap_lock);
>>> +
>>> +    return 0;
>>> +}
>>> +EXPORT_SYMBOL(dump_memory_map);
>>>
>>>
>>> Thanks,
>>> JM