profiling: fix sampling step on 64-bit big-endian systems

read_profile() stores the sampling step in an unsigned long but copies
only four bytes to userspace.  On 64-bit big-endian systems (not common
obviously), this copies the upper 32 bits and discards the rest, causing
/proc/profile to report zero for normal shift values.

Cast to unsigned int so we get the correct 4 bytes, while keeping the
shift calculation in unsigned long.

A small C reproducer under qemu-s390x reproduced this and proved the fix
works for prof_shift=2.

Link: https://lore.kernel.org/20261020101225.917959-1-thnkslprpt@gmail.com
Fixes: 2d186afd04d6 ("profiling: fix shift-out-of-bounds bugs")
Signed-off-by: Avi Weiss <thnkslprpt@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Bradley Morgan <brads@mainlining.org>

0 files changed, 0 insertions, 0 deletions