Nobody ever tried to self destruct by unmapping whole address space at once:

        munmap((void *)0, (1ULL << 47) - 4096);

Doing this produces 2 warnings for zero-length vmalloc allocations:

a.out[1353]: segfault at 7f80bcc4b757 ip 00007f80bcc4b757 sp 00007fff683939b8 
error 14
a.out: vmalloc: allocation failure: 0 bytes, mode:0xcc0(GFP_KERNEL), 
nodemask=(null)
        ...
a.out: vmalloc: allocation failure: 0 bytes, mode:0xcc0(GFP_KERNEL), 
nodemask=(null)
        ...

Fix is to switch to kvmalloc().

Steps to reproduce:

        // vsyscall=none
        #include <sys/mman.h>
        #include <sys/resource.h>
        int main(void)
        {
                setrlimit(RLIMIT_CORE, &(struct rlimit){RLIM_INFINITY, 
RLIM_INFINITY});
                munmap((void *)0, (1ULL << 47) - 4096);
                return 0;
        }

Signed-off-by: Alexey Dobriyan <adobri...@gmail.com>
---

 fs/binfmt_elf.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1608,8 +1608,8 @@ static int fill_files_note(struct memelfnote *note)
        if (size >= MAX_FILE_NOTE_SIZE) /* paranoia check */
                return -EINVAL;
        size = round_up(size, PAGE_SIZE);
-       data = vmalloc(size);
-       if (!data)
+       data = kvmalloc(size, GFP_KERNEL);
+       if (ZERO_OR_NULL_PTR(data))
                return -ENOMEM;
 
        start_end_ofs = data + 2;
@@ -1626,7 +1626,7 @@ static int fill_files_note(struct memelfnote *note)
                filename = file_path(file, name_curpos, remaining);
                if (IS_ERR(filename)) {
                        if (PTR_ERR(filename) == -ENAMETOOLONG) {
-                               vfree(data);
+                               kvfree(data);
                                size = size * 5 / 4;
                                goto alloc;
                        }
@@ -1919,7 +1919,7 @@ static void free_note_info(struct elf_note_info *info)
                kfree(t);
        }
        kfree(info->psinfo.data);
-       vfree(info->files.data);
+       kvfree(info->files.data);
 }
 
 #else
@@ -2135,7 +2135,7 @@ static void free_note_info(struct elf_note_info *info)
 
        /* Free data possibly allocated by fill_files_note(): */
        if (info->notes_files)
-               vfree(info->notes_files->data);
+               kvfree(info->notes_files->data);
 
        kfree(info->prstatus);
        kfree(info->psinfo);
@@ -2281,8 +2281,8 @@ static int elf_core_dump(struct coredump_params *cprm)
 
        if (segs - 1 > ULONG_MAX / sizeof(*vma_filesz))
                goto end_coredump;
-       vma_filesz = vmalloc((segs - 1) * sizeof(*vma_filesz));
-       if (!vma_filesz)
+       vma_filesz = kvmalloc((segs - 1) * sizeof(*vma_filesz), GFP_KERNEL);
+       if (ZERO_OR_NULL_PTR(vma_filesz))
                goto end_coredump;
 
        for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
@@ -2389,7 +2389,7 @@ static int elf_core_dump(struct coredump_params *cprm)
 cleanup:
        free_note_info(&info);
        kfree(shdr4extnum);
-       vfree(vma_filesz);
+       kvfree(vma_filesz);
        kfree(phdr4note);
        kfree(elf);
 out:

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