Files
msm-5.15/include/linux
Josh Poimboeuf 3d1e236022 objtool: Prevent GCC from merging annotate_unreachable()
0-day bot reported some new objtool warnings which were caused by the
new annotate_unreachable() macro:

  fs/afs/flock.o: warning: objtool: afs_do_unlk()+0x0: duplicate frame pointer save
  fs/afs/flock.o: warning: objtool: afs_do_unlk()+0x0: frame pointer state mismatch
  fs/btrfs/delayed-inode.o: warning: objtool: btrfs_delete_delayed_dir_index()+0x0: duplicate frame pointer save
  fs/btrfs/delayed-inode.o: warning: objtool: btrfs_delete_delayed_dir_index()+0x0: frame pointer state mismatch
  fs/dlm/lock.o: warning: objtool: _grant_lock()+0x0: duplicate frame pointer save
  fs/dlm/lock.o: warning: objtool: _grant_lock()+0x0: frame pointer state mismatch
  fs/ocfs2/alloc.o: warning: objtool: ocfs2_mv_path()+0x0: duplicate frame pointer save
  fs/ocfs2/alloc.o: warning: objtool: ocfs2_mv_path()+0x0: frame pointer state mismatch

It turns out that, for older versions of GCC, if a function has multiple
BUG() incantations, GCC will sometimes merge the corresponding
annotate_unreachable() inline asm statements into a single block.  That
has the undesirable effect of removing one of the entries in the
__unreachable section, confusing objtool greatly.

A workaround for this issue is to ensure that each instance of the
inline asm statement uses a different label, so that GCC sees the
statements are unique and leaves them alone.  The inline asm ‘%=’ token
could be used for that, but unfortunately older versions of GCC don't
support it.  So I implemented a poor man's version of it with the
__LINE__ macro.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
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>
Fixes: d1091c7fa3 ("objtool: Improve detection of BUG() and other dead ends")
Link: http://lkml.kernel.org/r/0c14b00baf9f68d1b0221ddb6c88b925181c8be8.1487997036.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-25 10:11:23 +01:00
..
2016-11-17 23:19:00 +01:00
2016-07-08 16:23:11 +02:00
2016-12-22 22:58:37 -05:00
2016-10-19 14:34:36 -04:00
2017-01-13 15:17:04 -07:00
2016-12-08 13:31:11 -05:00
2016-08-11 09:41:35 -06:00
2016-10-25 11:08:28 +08:00
2016-12-08 16:37:33 -08:00
2016-09-27 21:20:53 -04:00
2016-10-07 18:46:30 -07:00
2016-12-05 19:01:16 -05:00
2016-10-28 08:48:16 -06:00
2016-11-25 10:15:13 -08:00
2016-12-05 19:01:16 -05:00
2017-01-16 14:03:31 -05:00
2016-12-25 17:21:22 +01:00
2016-12-25 17:21:22 +01:00
2016-11-30 14:36:01 +11:00
2016-09-14 09:18:09 -06:00
2016-08-10 11:23:44 -04:00
2016-12-12 18:55:06 -08:00
2016-12-25 17:21:23 +01:00
2016-09-27 12:33:47 +02:00
2016-12-06 11:05:46 +01:00
2016-07-29 12:17:52 -07:00
2016-08-28 23:32:41 -04:00
2016-11-16 18:32:02 -05:00
2016-12-19 17:29:44 -05:00
2016-12-12 18:55:07 -08:00
2016-11-10 17:03:35 +01:00
2016-12-06 10:17:03 +02:00
2016-10-31 16:18:30 -04:00
2016-10-14 11:36:59 -07:00
2016-07-12 19:25:38 -07:00
2016-09-27 21:52:00 -04:00
2016-11-15 16:34:27 -08:00
2016-07-06 10:51:14 +01:00
2016-10-31 15:45:18 -07:00
2016-10-05 18:23:36 -04:00
2017-01-10 18:31:55 -08:00
2016-12-25 17:21:22 +01:00
2017-01-10 18:31:55 -08:00
2016-07-19 17:43:38 +03:00
2016-12-09 22:12:21 -05:00
2016-12-12 18:55:08 -08:00
2016-12-25 17:21:22 +01:00