Linus,
Russell King was reporting lots of warnings when he compiled his kernel
with ftrace enabled. With some investigation it was discovered that it
was his compile setup. He was using ccache with hard links, which allowed
recordmcount to process the same .o twice. When this happens, recordmcount
will detect that it was already done and give a warning about it.
Russell fixed this by having recordmcount detect that the object file
has more than one hard link, and if it does, it unlinks the object file
after it maps it and processes then. This appears to fix the issue.
Please pull the latest trace-v4.4-rc4 tree, which can be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v4.4-rc4
Tag SHA1: 4a56e8c7c0562310d74910b17429134d44418cc7
Head SHA1: 420cbb014db5594f8e503fc578fdd146a458f92c
Russell King (1):
scripts: recordmcount: break hardlinks
----
scripts/recordmcount.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
---------------------------
commit 420cbb014db5594f8e503fc578fdd146a458f92c
Author: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Date: Fri Dec 11 12:09:03 2015 +0000
scripts: recordmcount: break hardlinks
recordmcount edits the file in-place, which can cause problems when
using ccache in hardlink mode. Arrange for recordmcount to break a
hardlinked object.
Link: http://lkml.kernel.org/r/E1a7MVT-0000et-62@xxxxxxxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx # 2.6.37+
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 698768bdc581..91705ef30402 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -211,6 +211,20 @@ static void *mmap_file(char const *fname)
addr = umalloc(sb.st_size);
uread(fd_map, addr, sb.st_size);
}
+ if (sb.st_nlink != 1) {
+ /* file is hard-linked, break the hard link */
+ close(fd_map);
+ if (unlink(fname) < 0) {
+ perror(fname);
+ fail_file();
+ }
+ fd_map = open(fname, O_RDWR | O_CREAT, sb.st_mode);
+ if (fd_map < 0) {
+ perror(fname);
+ fail_file();
+ }
+ uwrite(fd_map, addr, sb.st_size);
+ }
return addr;
}
--
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