fs: fix llseek() result for files with unsigned offsets

sys_llseek() treats a negative result from vfs_llseek() as an error and
returns it truncated to int instead of storing it in *result.  For a
file with FOP_UNSIGNED_OFFSET a valid offset can have the top bit set,
so the seek succeeds but userspace gets a bogus return value and an
untouched result buffer.  ksys_lseek() has no such check and returns
the offset as is.

Store the offset when the file has unsigned offsets too, still treating
a value in the errno range as an error so a real failure from
->llseek() is reported.

On sparc64, where userspace is mapped above 2^63 and glibc's lseek()
uses _llseek, this makes lseek() on /proc/PID/mem return the offset it
seeked to instead of its low 32 bits.

Signed-off-by: Stian Halseth <stian@itx.no>
Link: https://patch.msgid.link/20260917151614.376867-2-stian@itx.no
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

0 files changed, 0 insertions, 0 deletions