Messages in this thread | | | From | John Stultz <> | Subject | [RFC][PATCH 0/5] Fixes for abs() usage on 64bit values | Date | Mon, 14 Sep 2015 18:05:19 -0700 |
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As noted in include/linux/kernel.h: "abs() should not be used for 64-bit types (s64, u64, long long) - use abs64() for those."
Unfortunately, there are quite a number of places where abs() was used w/ 64bit values in the kernel, and the results are then silently capped to 32-bit values on 32-bit systems.
This series tries to address the problematic sites I found, and then introduces a patch which modifies abs() so that the build will fail if a 64-bit type is passed to it on a 32-bit machine.
I'm sure there are additional sites that will need fixing, but hopefully this will make them easy to find.
Comments and feedback would be greatly appreciated!
Thanks -john
Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Dave Chinner <dchinner@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Joe Perches <joe@perches.com>
John Stultz (5): clocksource: Fix abs() usage w/ 64bit values time: Fix abs() usage with 64-bit values. ext4: Fix abs() usage in ext4_mb_check_group_pa percpu: Fix abs() usage in percpu_counter_compare() abs(): Provide build error on passing 64bit value to abs()
fs/ext4/mballoc.c | 4 ++-- include/linux/kernel.h | 3 +++ kernel/time/clocksource.c | 2 +- kernel/time/timekeeping.c | 2 +- lib/percpu_counter.c | 2 +- 5 files changed, 8 insertions(+), 5 deletions(-)
-- 1.9.1
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