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
