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| author | Stanislaw Gruszka <sgruszka@redhat.com> | 2019-03-07 16:28:18 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-04-20 09:07:54 +0200 |
| commit | afac7da6d8560c78c6a6d61adb27fbeb064f7a26 (patch) | |
| tree | 131f9137e3aab25b6a04e90be92f0f26f984c23f /lib/locking-selftest-spin-hardirq.h | |
| parent | 057a0da1899f00a4ac9a4c4c452cf2cf652bdbf0 (diff) | |
lib/div64.c: off by one in shift
[ Upstream commit cdc94a37493135e355dfc0b0e086d84e3eadb50d ]
fls counts bits starting from 1 to 32 (returns 0 for zero argument). If
we add 1 we shift right one bit more and loose precision from divisor,
what cause function incorect results with some numbers.
Corrected code was tested in user-space, see bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=202391
Link: http://lkml.kernel.org/r/1548686944-11891-1-git-send-email-sgruszka@redhat.com
Fixes: 658716d19f8f ("div64_u64(): improve precision on 32bit platforms")
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Reported-by: Siarhei Volkau <lis8215@gmail.com>
Tested-by: Siarhei Volkau <lis8215@gmail.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'lib/locking-selftest-spin-hardirq.h')
0 files changed, 0 insertions, 0 deletions