The patch titled
Subject: fs/binfmt_elf.c: coredump: allow process with empty address space to coredump
has been added to the -mm tree. Its filename is
elf-coredump-allow-process-with-empty-address-space-to-coredump.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/elf-coredump-allow-process-with-empty-address-space-to-coredump.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/elf-coredump-allow-process-with-empty-address-space-to-coredump.patch
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------------------------------------------------------
From: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Subject: fs/binfmt_elf.c: coredump: allow process with empty address space to coredump
Unmapping whole address space at once with
munmap(0, (1ULL<<47) - 4096)
or equivalent will create empty coredump.
It is silly way to exit, however registers content may still be useful.
The right to coredump is fundamental right of a process!
Link: http://lkml.kernel.org/r/20191222150137.GA1277@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/binfmt_elf.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
--- a/fs/binfmt_elf.c~elf-coredump-allow-process-with-empty-address-space-to-coredump
+++ a/fs/binfmt_elf.c
@@ -1595,6 +1595,10 @@ static int fill_files_note(struct memelf
if (size >= MAX_FILE_NOTE_SIZE) /* paranoia check */
return -EINVAL;
size = round_up(size, PAGE_SIZE);
+ /*
+ * "size" can be 0 here legitimately.
+ * Let it ENOMEM and omit NT_FILE section which will be empty anyway.
+ */
data = kvmalloc(size, GFP_KERNEL);
if (ZERO_OR_NULL_PTR(data))
return -ENOMEM;
@@ -2257,9 +2261,13 @@ static int elf_core_dump(struct coredump
dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
+ /*
+ * Zero vma process will get ZERO_SIZE_PTR here.
+ * Let coredump continue for register state at least.
+ */
vma_filesz = kvmalloc(array_size(sizeof(*vma_filesz), (segs - 1)),
GFP_KERNEL);
- if (ZERO_OR_NULL_PTR(vma_filesz))
+ if (!vma_filesz)
goto end_coredump;
for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
_
Patches currently in -mm which might be from adobriyan@xxxxxxxxx are
ramfs-support-o_tmpfile.patch
elf-smaller-code-generation-around-auxv-vector-fill.patch
elf-fix-start_code-calculation.patch
elf-dont-copy-elf-header-around.patch
elf-better-codegen-around-current-mm.patch
elf-make-bad_addr-unlikely.patch
elf-coredump-allocate-core-elf-header-on-stack.patch
elf-coredump-delete-duplicated-overflow-check.patch
elf-coredump-allow-process-with-empty-address-space-to-coredump.patch
execve-warn-if-process-starts-with-executable-stack.patch
