The patch titled
Subject: vmcore: rearrange program headers without assuming consecutive PT_NOTE entries
has been removed from the -mm tree. Its filename was
vmcore-rearrange-program-headers-without-assuming-consequtive-pt_note-entries.patch
This patch was dropped because it was nacked
------------------------------------------------------
From: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx>
Subject: vmcore: rearrange program headers without assuming consecutive PT_NOTE entries
Current code assumes all PT_NOTE headers are placed at the beginning of
program header table and they are consecutive. But the assumption could
be broken by future changes on either kexec-tools or the 1st kernel. This
patch removes the assumption and rearranges program headers as the
following conditions are satisfied:
- PT_NOTE entry is unique at the first entry,
- the order of program headers are unchanged during this
rearrangement, only their positions are changed in positive
direction.
- unused part that occurs in the bottom of program headers are filled
with 0.
Also, this patch adds one exceptional case where the number of PT_NOTE
entries is somehow 0. Then, immediately go out of the function.
Signed-off-by: HATAYAMA Daisuke <d.hatayama@xxxxxxxxxxxxxx>
Cc: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/vmcore.c | 92 ++++++++++++++++++++++++++++++++++++---------
1 file changed, 74 insertions(+), 18 deletions(-)
diff -puN fs/proc/vmcore.c~vmcore-rearrange-program-headers-without-assuming-consequtive-pt_note-entries fs/proc/vmcore.c
--- a/fs/proc/vmcore.c~vmcore-rearrange-program-headers-without-assuming-consequtive-pt_note-entries
+++ a/fs/proc/vmcore.c
@@ -251,8 +251,7 @@ static u64 __init get_vmcore_size_elf32(
static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
struct list_head *vc_list)
{
- int i, nr_ptnote=0, rc=0;
- char *tmp;
+ int i, j, nr_ptnote=0, i_ptnote, rc=0;
Elf64_Ehdr *ehdr_ptr;
Elf64_Phdr phdr, *phdr_ptr;
Elf64_Nhdr *nhdr_ptr;
@@ -301,6 +300,39 @@ static int __init merge_note_headers_elf
kfree(notes_section);
}
+ if (nr_ptnote == 0)
+ goto out;
+
+ phdr_ptr = (Elf64_Phdr *)(elfptr + ehdr_ptr->e_phoff);
+
+ /* Remove unwanted PT_NOTE program headers. */
+
+ /* - 1st pass shifts non-PT_NOTE entries until the first
+ PT_NOTE entry. */
+ i_ptnote = -1;
+ for (i = 0; i < ehdr_ptr->e_phnum; ++i) {
+ if (phdr_ptr[i].p_type == PT_NOTE) {
+ i_ptnote = i;
+ break;
+ }
+ }
+ BUG_ON(i_ptnote == -1); /* impossible case since nr_ptnote > 0. */
+ memmove(phdr_ptr + 1, phdr_ptr, i_ptnote * sizeof(Elf64_Phdr));
+
+ /* - 2nd pass moves the remaining non-PT_NOTE entries under
+ the first PT_NOTE entry. */
+ for (i = j = i_ptnote + 1; i < ehdr_ptr->e_phnum; i++) {
+ if (phdr_ptr[i].p_type != PT_NOTE) {
+ memmove(phdr_ptr + j, phdr_ptr + i,
+ sizeof(Elf64_Phdr));
+ j++;
+ }
+ }
+
+ /* - Finally, fill unused part with 0. */
+ memset(phdr_ptr + ehdr_ptr->e_phnum - (nr_ptnote - 1), 0,
+ (nr_ptnote - 1) * sizeof(Elf64_Phdr));
+
/* Prepare merged PT_NOTE program header. */
phdr.p_type = PT_NOTE;
phdr.p_flags = 0;
@@ -312,18 +344,14 @@ static int __init merge_note_headers_elf
phdr.p_align = 0;
/* Add merged PT_NOTE program header*/
- tmp = elfptr + ehdr_ptr->e_phoff;
- memcpy(tmp, &phdr, sizeof(phdr));
- tmp += sizeof(phdr);
+ memcpy(phdr_ptr, &phdr, sizeof(Elf64_Phdr));
- /* Remove unwanted PT_NOTE program headers. */
- i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
- *elfsz = *elfsz - i;
- memmove(tmp, tmp+i, ((*elfsz)-ehdr_ptr->e_phoff-sizeof(Elf64_Phdr)));
+ *elfsz = *elfsz - (nr_ptnote - 1) * sizeof(Elf64_Phdr);
/* Modify e_phnum to reflect merged headers. */
ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
+out:
return 0;
}
@@ -331,8 +359,7 @@ static int __init merge_note_headers_elf
static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
struct list_head *vc_list)
{
- int i, nr_ptnote=0, rc=0;
- char *tmp;
+ int i, j, nr_ptnote=0, i_ptnote, rc=0;
Elf32_Ehdr *ehdr_ptr;
Elf32_Phdr phdr, *phdr_ptr;
Elf32_Nhdr *nhdr_ptr;
@@ -381,6 +408,39 @@ static int __init merge_note_headers_elf
kfree(notes_section);
}
+ if (nr_ptnote == 0)
+ goto out;
+
+ phdr_ptr = (Elf32_Phdr *)(elfptr + ehdr_ptr->e_phoff);
+
+ /* Remove unwanted PT_NOTE program headers. */
+
+ /* - 1st pass shifts non-PT_NOTE entries until the first
+ PT_NOTE entry. */
+ i_ptnote = -1;
+ for (i = 0; i < ehdr_ptr->e_phnum; ++i) {
+ if (phdr_ptr[i].p_type == PT_NOTE) {
+ i_ptnote = i;
+ break;
+ }
+ }
+ BUG_ON(i_ptnote == -1); /* impossible case since nr_ptnote > 0. */
+ memmove(phdr_ptr + 1, phdr_ptr, i_ptnote * sizeof(Elf32_Phdr));
+
+ /* - 2nd pass moves the remaining non-PT_NOTE entries under
+ the first PT_NOTE entry. */
+ for (i = j = i_ptnote + 1; i < ehdr_ptr->e_phnum; i++) {
+ if (phdr_ptr[i].p_type != PT_NOTE) {
+ memmove(phdr_ptr + j, phdr_ptr + i,
+ sizeof(Elf32_Phdr));
+ j++;
+ }
+ }
+
+ /* - Finally, fill unused part with 0. */
+ memset(phdr_ptr + ehdr_ptr->e_phnum - (nr_ptnote - 1), 0,
+ (nr_ptnote - 1) * sizeof(Elf32_Phdr));
+
/* Prepare merged PT_NOTE program header. */
phdr.p_type = PT_NOTE;
phdr.p_flags = 0;
@@ -392,18 +452,14 @@ static int __init merge_note_headers_elf
phdr.p_align = 0;
/* Add merged PT_NOTE program header*/
- tmp = elfptr + ehdr_ptr->e_phoff;
- memcpy(tmp, &phdr, sizeof(phdr));
- tmp += sizeof(phdr);
+ memcpy(phdr_ptr, &phdr, sizeof(Elf32_Phdr));
- /* Remove unwanted PT_NOTE program headers. */
- i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
- *elfsz = *elfsz - i;
- memmove(tmp, tmp+i, ((*elfsz)-ehdr_ptr->e_phoff-sizeof(Elf32_Phdr)));
+ *elfsz = *elfsz - (nr_ptnote - 1) * sizeof(Elf32_Phdr);
/* Modify e_phnum to reflect merged headers. */
ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
+out:
return 0;
}
_
Patches currently in -mm which might be from d.hatayama@xxxxxxxxxxxxxx are
vmcore-sysfs-export-elf-note-segment-size-instead-of-vmcoreinfo-data-size.patch
vmcore-allocate-buffer-for-elf-headers-on-page-size-alignment.patch
vmcore-round-up-buffer-size-of-elf-headers-by-page_size.patch
vmcore-procfs-introduce-a-flag-to-distinguish-objects-copied-in-2nd-kernel.patch
vmcore-copy-non-page-size-aligned-head-and-tail-pages-in-2nd-kernel.patch
vmcore-modify-vmcore-clean-up-function-to-free-buffer-on-2nd-kernel.patch
vmcore-clean-up-read_vmcore.patch
vmcore-read-buffers-for-vmcore-objects-copied-from-old-memory.patch
vmcore-allocate-per-cpu-crash_notes-objects-on-page-size-boundary.patch
kexec-allocate-vmcoreinfo-note-buffer-on-page-size-boundary.patch
kexec-elf-introduce-nt_vmcore_debuginfo-note-type.patch
elf-introduce-nt_vmcore_pad-type.patch
kexec-fill-note-buffers-by-nt_vmcore_pad-notes-in-page-size-boundary.patch
vmcore-check-nt_vmcore_pad-as-a-mark-indicating-the-end-of-elf-note-buffer.patch
vmcore-check-if-vmcore-objects-satify-mmaps-page-size-boundary-requirement.patch
vmcore-round-up-offset-of-vmcore-object-in-page-size-boundary.patch
vmcore-count-holes-generated-by-round-up-operation-for-vmcore-size.patch
vmcore-introduce-mmap_vmcore.patch
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