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| author | Kirill A. Shutemov <[email protected]> | 2023-04-06 07:25:29 +0000 |
|---|---|---|
| committer | Andrew Morton <[email protected]> | 2023-04-18 23:29:42 +0000 |
| commit | 59f876fb9d68a4d8c20305d7a7a0daf4ee9478a8 (patch) | |
| tree | 4b4d6b6bfd75ea2623b77598ca8fa445a027b526 /mm/mm_init.c | |
| parent | sync mm-stable with mm-hotfixes-stable to pick up depended-upon upstream changes (diff) | |
| download | kernel-59f876fb9d68a4d8c20305d7a7a0daf4ee9478a8.tar.gz kernel-59f876fb9d68a4d8c20305d7a7a0daf4ee9478a8.zip | |
mm: avoid passing 0 to __ffs()
23baf831a32c ("mm, treewide: redefine MAX_ORDER sanely") results in
various boot failures (hang) on arm targets Debug messages reveal the
reason.
########### MAX_ORDER=10 start=0 __ffs(start)=-1 min()=10 min_t=-1
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
If start==0, __ffs(start) returns 0xfffffff or (as int) -1, which min_t()
interprets as such, while min() apparently uses the returned unsigned long
value. Obviously a negative order isn't received well by the rest of the
code.
[[email protected]: fix comment, per Mike]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 23baf831a32c ("mm, treewide: redefine MAX_ORDER sanely")
Signed-off-by: "Kirill A. Shutemov" <[email protected]>
Reported-by: Guenter Roeck <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Reviewed-by: Mike Rapoport (IBM) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Diffstat (limited to 'mm/mm_init.c')
0 files changed, 0 insertions, 0 deletions