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| author |   Mikulas Patocka <mpatocka@redhat.com> | 2018-05-30 08:19:22 -0400 |
|---|---|---|
| committer |   Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-06-04 17:28:20 -0400 |
| commit | 2026d35741f2c3ece73c11eb7e4a15d7c2df9ebe (patch) | |
| tree | f05eb8233131e271c1844dd17c8053e450d607b7 /lib/test_overflow.c | |
| parent | ring-buffer: Fix typo in comment (diff) | |
| download | linux-dev-2026d35741f2c3ece73c11eb7e4a15d7c2df9ebe.tar.xz linux-dev-2026d35741f2c3ece73c11eb7e4a15d7c2df9ebe.zip | |
branch-check: fix long->int truncation when profiling branches
The function __builtin_expect returns long type (see the gcc
documentation), and so do macros likely and unlikely. Unfortunatelly, when
CONFIG_PROFILE_ANNOTATED_BRANCHES is selected, the macros likely and
unlikely expand to __branch_check__ and __branch_check__ truncates the
long type to int. This unintended truncation may cause bugs in various
kernel code (we found a bug in dm-writecache because of it), so it's
better to fix __branch_check__ to return long.
Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1805300818140.24812@file01.intranet.prod.int.rdu2.redhat.com
Cc: Ingo Molnar <mingo@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 1f0d69a9fc815 ("tracing: profile likely and unlikely annotations")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'lib/test_overflow.c')
0 files changed, 0 insertions, 0 deletions