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* [PATCH] objtool: Do not retrieve data from empty sections
@ 2017-09-15  7:15 Josh Poimboeuf
  2017-09-15  8:43 ` [tip:core/urgent] " tip-bot for Petr Vandrovec
  2017-09-15  9:37 ` tip-bot for Petr Vandrovec
  0 siblings, 2 replies; 3+ messages in thread
From: Josh Poimboeuf @ 2017-09-15  7:15 UTC (permalink / raw)
  To: Ingo Molnar; +Cc: linux-kernel, Petr Vandrovec

From: Petr Vandrovec <petr@vandrovec.name>

Binutils 2.29-9 in Debian return an error when elf_getdata is invoked
on empty section (.note.GNU-stack in all kernel files), causing
immediate failure of kernel build with:

elf_getdata: can't manipulate null section

As nothing is done with sections that have zero size, just do not
retrieve their data at all.

Signed-off-by: Petr Vandrovec <petr@vandrovec.name>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 tools/objtool/elf.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 6e9f980a7d26..99eccd23023d 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -175,19 +175,20 @@ static int read_sections(struct elf *elf)
 			return -1;
 		}
 
-		sec->data = elf_getdata(s, NULL);
-		if (!sec->data) {
-			WARN_ELF("elf_getdata");
-			return -1;
-		}
-
-		if (sec->data->d_off != 0 ||
-		    sec->data->d_size != sec->sh.sh_size) {
-			WARN("unexpected data attributes for %s", sec->name);
-			return -1;
+		if (sec->sh.sh_size != 0) {
+			sec->data = elf_getdata(s, NULL);
+			if (!sec->data) {
+				WARN_ELF("elf_getdata");
+				return -1;
+			}
+			if (sec->data->d_off != 0 ||
+			    sec->data->d_size != sec->sh.sh_size) {
+				WARN("unexpected data attributes for %s",
+				     sec->name);
+				return -1;
+			}
 		}
-
-		sec->len = sec->data->d_size;
+		sec->len = sec->sh.sh_size;
 	}
 
 	/* sanity check, one more call to elf_nextscn() should return NULL */
-- 
2.13.5

^ permalink raw reply	[flat|nested] 3+ messages in thread

* [tip:core/urgent] objtool: Do not retrieve data from empty sections
  2017-09-15  7:15 [PATCH] objtool: Do not retrieve data from empty sections Josh Poimboeuf
@ 2017-09-15  8:43 ` tip-bot for Petr Vandrovec
  2017-09-15  9:37 ` tip-bot for Petr Vandrovec
  1 sibling, 0 replies; 3+ messages in thread
From: tip-bot for Petr Vandrovec @ 2017-09-15  8:43 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: dzickus, petr, tglx, jpoimboe, mingo, hpa, peterz, linux-kernel,
	torvalds

Commit-ID:  7156b7141a037420a3cd99dbc1559e0235f57c07
Gitweb:     http://git.kernel.org/tip/7156b7141a037420a3cd99dbc1559e0235f57c07
Author:     Petr Vandrovec <petr@vandrovec.name>
AuthorDate: Fri, 15 Sep 2017 02:15:05 -0500
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 15 Sep 2017 10:30:31 +0200

objtool: Do not retrieve data from empty sections

Binutils 2.29-9 in Debian return an error when elf_getdata is invoked
on empty section (.note.GNU-stack in all kernel files), causing
immediate failure of kernel build with:

  elf_getdata: can't manipulate null section

As nothing is done with sections that have zero size, just do not
retrieve their data at all.

Signed-off-by: Petr Vandrovec <petr@vandrovec.name>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/2ce30a44349065b70d0f00e71e286dc0cbe745e6.1505459652.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 tools/objtool/elf.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 1e89a5f..b4cd8bc 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -175,19 +175,20 @@ static int read_sections(struct elf *elf)
 			return -1;
 		}
 
-		sec->data = elf_getdata(s, NULL);
-		if (!sec->data) {
-			WARN_ELF("elf_getdata");
-			return -1;
-		}
-
-		if (sec->data->d_off != 0 ||
-		    sec->data->d_size != sec->sh.sh_size) {
-			WARN("unexpected data attributes for %s", sec->name);
-			return -1;
+		if (sec->sh.sh_size != 0) {
+			sec->data = elf_getdata(s, NULL);
+			if (!sec->data) {
+				WARN_ELF("elf_getdata");
+				return -1;
+			}
+			if (sec->data->d_off != 0 ||
+			    sec->data->d_size != sec->sh.sh_size) {
+				WARN("unexpected data attributes for %s",
+				     sec->name);
+				return -1;
+			}
 		}
-
-		sec->len = sec->data->d_size;
+		sec->len = sec->sh.sh_size;
 	}
 
 	/* sanity check, one more call to elf_nextscn() should return NULL */

^ permalink raw reply	[flat|nested] 3+ messages in thread

* [tip:core/urgent] objtool: Do not retrieve data from empty sections
  2017-09-15  7:15 [PATCH] objtool: Do not retrieve data from empty sections Josh Poimboeuf
  2017-09-15  8:43 ` [tip:core/urgent] " tip-bot for Petr Vandrovec
@ 2017-09-15  9:37 ` tip-bot for Petr Vandrovec
  1 sibling, 0 replies; 3+ messages in thread
From: tip-bot for Petr Vandrovec @ 2017-09-15  9:37 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: mingo, petr, hpa, tglx, linux-kernel, torvalds, peterz, jpoimboe

Commit-ID:  df968c9329f6e5cf3596a0a54adb6f749747a746
Gitweb:     http://git.kernel.org/tip/df968c9329f6e5cf3596a0a54adb6f749747a746
Author:     Petr Vandrovec <petr@vandrovec.name>
AuthorDate: Fri, 15 Sep 2017 02:15:05 -0500
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 15 Sep 2017 11:31:50 +0200

objtool: Do not retrieve data from empty sections

Binutils 2.29-9 in Debian return an error when elf_getdata is invoked
on empty section (.note.GNU-stack in all kernel files), causing
immediate failure of kernel build with:

  elf_getdata: can't manipulate null section

As nothing is done with sections that have zero size, just do not
retrieve their data at all.

Signed-off-by: Petr Vandrovec <petr@vandrovec.name>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/2ce30a44349065b70d0f00e71e286dc0cbe745e6.1505459652.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 tools/objtool/elf.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 1e89a5f..b4cd8bc 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -175,19 +175,20 @@ static int read_sections(struct elf *elf)
 			return -1;
 		}
 
-		sec->data = elf_getdata(s, NULL);
-		if (!sec->data) {
-			WARN_ELF("elf_getdata");
-			return -1;
-		}
-
-		if (sec->data->d_off != 0 ||
-		    sec->data->d_size != sec->sh.sh_size) {
-			WARN("unexpected data attributes for %s", sec->name);
-			return -1;
+		if (sec->sh.sh_size != 0) {
+			sec->data = elf_getdata(s, NULL);
+			if (!sec->data) {
+				WARN_ELF("elf_getdata");
+				return -1;
+			}
+			if (sec->data->d_off != 0 ||
+			    sec->data->d_size != sec->sh.sh_size) {
+				WARN("unexpected data attributes for %s",
+				     sec->name);
+				return -1;
+			}
 		}
-
-		sec->len = sec->data->d_size;
+		sec->len = sec->sh.sh_size;
 	}
 
 	/* sanity check, one more call to elf_nextscn() should return NULL */

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2017-09-15  9:40 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-09-15  7:15 [PATCH] objtool: Do not retrieve data from empty sections Josh Poimboeuf
2017-09-15  8:43 ` [tip:core/urgent] " tip-bot for Petr Vandrovec
2017-09-15  9:37 ` tip-bot for Petr Vandrovec

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