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| author | Rasmus Villemoes | 2017-07-11 00:49:26 +0200 |
|---|---|---|
| committer | Linus Torvalds | 2017-07-11 01:32:32 +0200 |
| commit | b002529d256307602c669d1886c0b953b52b8700 (patch) | |
| tree | 9219954404a5b6124356dd8a1785d6f5c0653126 /mm/swap_slots.c | |
| parent | fs/proc/task_mmu.c: remove obsolete comment in show_map_vma() (diff) | |
| download | kernel-qcow2-linux-b002529d256307602c669d1886c0b953b52b8700.tar.gz kernel-qcow2-linux-b002529d256307602c669d1886c0b953b52b8700.tar.xz kernel-qcow2-linux-b002529d256307602c669d1886c0b953b52b8700.zip | |
mm/page_alloc.c: eliminate unsigned confusion in __rmqueue_fallback
Since current_order starts as MAX_ORDER-1 and is then only decremented,
the second half of the loop condition seems superfluous. However, if
order is 0, we may decrement current_order past 0, making it UINT_MAX.
This is obviously too subtle ([1], [2]).
Since we need to add some comment anyway, change the two variables to
signed, making the counting-down for loop look more familiar, and
apparently also making gcc generate slightly smaller code.
[1] https://lkml.org/lkml/2016/6/20/493
[2] https://lkml.org/lkml/2017/6/19/345
[akpm@linux-foundation.org: fix up reject fixupping]
Link: http://lkml.kernel.org/r/20170621185529.2265-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reported-by: Hao Lee <haolee.swjtu@gmail.com>
Acked-by: Wei Yang <weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/swap_slots.c')
0 files changed, 0 insertions, 0 deletions