Add MMF_DUMP_ELF_HEADERS

This adds the MMF_DUMP_ELF_HEADERS option to /proc/pid/coredump_filter.
This dumps the first page (only) of a private file mapping if it appears to
be a mapping of an ELF file.  Including these pages in the core dump may
give sufficient identifying information to associate the original DSO and
executable file images and their debugging information with a core file in
a generic way just from its contents (e.g.  when those binaries were built
with ld --build-id).  I expect this to become the default behavior
eventually.  Existing versions of gdb can be confused by the core dumps it
creates, so it won't enabled by default for some time to come.  Soon many
people will have systems with a gdb that handle these dumps, so they can
arrange to set the bit at boot and have it inherited system-wide.

This also cleans up the checking of the MMF_DUMP_* flag bits, which did not
need to be using atomic macros.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index e643357eda05..cb952bc225e4 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -359,8 +359,9 @@ extern int get_dumpable(struct mm_struct *mm);
 #define MMF_DUMP_ANON_SHARED    3
 #define MMF_DUMP_MAPPED_PRIVATE 4
 #define MMF_DUMP_MAPPED_SHARED  5
+#define MMF_DUMP_ELF_HEADERS    6
 #define MMF_DUMP_FILTER_SHIFT   MMF_DUMPABLE_BITS
-#define MMF_DUMP_FILTER_BITS    4
+#define MMF_DUMP_FILTER_BITS    5
 #define MMF_DUMP_FILTER_MASK \
         (((1 << MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT)
 #define MMF_DUMP_FILTER_DEFAULT \