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From: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
To: vgoyal@redhat.com, ebiederm@xmission.com, cpw@sgi.com,
	kumagai-atsushi@mxc.nes.nec.co.jp, lisa.mitchell@hp.com,
	heiko.carstens@de.ibm.com, akpm@linux-foundation.org
Cc: kexec@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 16/20] vmcore: check NT_VMCORE_PAD as a mark indicating the end of ELF note buffer
Date: Sat, 02 Mar 2013 17:37:20 +0900	[thread overview]
Message-ID: <20130302083720.31252.92900.stgit@localhost6.localdomain6> (raw)
In-Reply-To: <20130302083447.31252.93914.stgit@localhost6.localdomain6>

Modern kernel marks the end of ELF note buffer with NT_VMCORE_PAD type
note in order to make the buffer satisfy mmap()'s page-size boundary
requirement. This patch makes finishing reading each buffer if the
note type now being read is NT_VMCORE_PAD type.

Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
---

 fs/proc/vmcore.c |   24 ++++++++++++++++++++++++
 1 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index c8899dc..e432946 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -259,12 +259,24 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 		}
 		nhdr_ptr = notes_section;
 		for (j = 0; j < max_sz; j += sz) {
+			char *name;
+
+			/* Old kernel marks the end of ELF note buffer
+			 * with empty header. */
 			if (nhdr_ptr->n_namesz == 0)
 				break;
 			sz = sizeof(Elf64_Nhdr) +
 				((nhdr_ptr->n_namesz + 3) & ~3) +
 				((nhdr_ptr->n_descsz + 3) & ~3);
 			real_sz += sz;
+
+			/* Modern kernel marks the end of ELF note
+			 * buffer with NT_VMCORE_PAD type note. */
+			name = (char *)(nhdr_ptr + 1);
+			if (strncmp(name, VMCOREINFO_NOTE_NAME,
+				    sizeof(VMCOREINFO_NOTE_NAME)) == 0
+			    && nhdr_ptr->n_type == NT_VMCORE_PAD)
+				break;
 			nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
 		}
 
@@ -369,12 +381,24 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
 		}
 		nhdr_ptr = notes_section;
 		for (j = 0; j < max_sz; j += sz) {
+			char *name;
+
+			/* Old kernel marks the end of ELF note buffer
+			 * with empty header. */
 			if (nhdr_ptr->n_namesz == 0)
 				break;
 			sz = sizeof(Elf32_Nhdr) +
 				((nhdr_ptr->n_namesz + 3) & ~3) +
 				((nhdr_ptr->n_descsz + 3) & ~3);
 			real_sz += sz;
+
+			/* Modern kernel marks the end of ELF note
+			 * buffer with NT_VMCORE_PAD type note. */
+			name = (char *)(nhdr_ptr + 1);
+			if (strncmp(name, VMCOREINFO_NOTE_NAME,
+				    sizeof(VMCOREINFO_NOTE_NAME)) == 0
+			    && nhdr_ptr->n_type == NT_VMCORE_PAD)
+				break;
 			nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
 		}
 


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  parent reply	other threads:[~2013-03-05  7:06 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-02  8:35 [PATCH v2 00/20] kdump, vmcore: support mmap() on /proc/vmcore HATAYAMA Daisuke
2013-03-02  8:35 ` [PATCH v2 01/20] vmcore: refer to e_phoff member explicitly HATAYAMA Daisuke
2013-03-05  7:35   ` Zhang Yanfei
2013-03-10  6:46     ` Zhang Yanfei
2013-03-11  0:31       ` HATAYAMA Daisuke
2013-03-11 17:36         ` Vivek Goyal
2013-03-02  8:35 ` [PATCH v2 02/20] vmcore: rearrange program headers without assuming consequtive PT_NOTE entries HATAYAMA Daisuke
2013-03-05  8:36   ` Zhang Yanfei
2013-03-05  9:02     ` HATAYAMA Daisuke
2013-03-05  9:35       ` Zhang Yanfei
2013-03-02  8:36 ` [PATCH v2 03/20] vmcore, sysfs: export ELF note segment size instead of vmcoreinfo data size HATAYAMA Daisuke
2013-03-05  9:29   ` Zhang Yanfei
2013-03-06  0:07   ` HATAYAMA Daisuke
2013-03-02  8:36 ` [PATCH v2 04/20] vmcore: allocate buffer for ELF headers on page-size alignment HATAYAMA Daisuke
2013-03-06  6:57   ` Zhang Yanfei
2013-03-06  9:14     ` HATAYAMA Daisuke
2013-03-02  8:36 ` [PATCH v2 05/20] vmcore: round up buffer size of ELF headers by PAGE_SIZE HATAYAMA Daisuke
2013-03-06 15:51   ` Yanfei Zhang
2013-03-02  8:36 ` [PATCH v2 06/20] vmcore, procfs: introduce a flag to distinguish objects copied in 2nd kernel HATAYAMA Daisuke
2013-03-06 15:55   ` Yanfei Zhang
2013-03-02  8:36 ` [PATCH v2 07/20] vmcore: copy non page-size aligned head and tail pages " HATAYAMA Daisuke
2013-03-10  6:16   ` Zhang Yanfei
2013-03-11  0:27     ` HATAYAMA Daisuke
2013-03-02  8:36 ` [PATCH v2 08/20] vmcore: modify vmcore clean-up function to free buffer on " HATAYAMA Daisuke
2013-03-02  8:36 ` [PATCH v2 09/20] vmcore: clean up read_vmcore() HATAYAMA Daisuke
2013-03-02  8:36 ` [PATCH v2 10/20] vmcore: read buffers for vmcore objects copied from old memory HATAYAMA Daisuke
2013-03-02  8:36 ` [PATCH v2 11/20] vmcore: allocate per-cpu crash_notes objects on page-size boundary HATAYAMA Daisuke
2013-03-02  8:36 ` [PATCH v2 12/20] kexec: allocate vmcoreinfo note buffer " HATAYAMA Daisuke
2013-03-02  8:37 ` [PATCH v2 13/20] kexec, elf: introduce NT_VMCORE_DEBUGINFO note type HATAYAMA Daisuke
2013-03-02  8:37 ` [PATCH v2 14/20] elf: introduce NT_VMCORE_PAD type HATAYAMA Daisuke
2013-03-02  8:37 ` [PATCH v2 15/20] kexec: fill note buffers by NT_VMCORE_PAD notes in page-size boundary HATAYAMA Daisuke
2013-03-07 10:11   ` Zhang Yanfei
2013-03-08  1:55     ` HATAYAMA Daisuke
2013-03-08 13:02       ` Yanfei Zhang
2013-03-09  3:46         ` HATAYAMA Daisuke
2013-03-10  2:33           ` Zhang Yanfei
2013-03-02  8:37 ` HATAYAMA Daisuke [this message]
2013-03-02  8:37 ` [PATCH v2 17/20] vmcore: check if vmcore objects satify mmap()'s page-size boundary requirement HATAYAMA Daisuke
2013-03-02  8:37 ` [PATCH v2 18/20] vmcore: round-up offset of vmcore object in page-size boundary HATAYAMA Daisuke
2013-03-02  8:37 ` [PATCH v2 19/20] vmcore: count holes generated by round-up operation for vmcore size HATAYAMA Daisuke
2013-03-02  8:37 ` [PATCH v2 20/20] vmcore: introduce mmap_vmcore() HATAYAMA Daisuke

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