On Fri, May 18, 2018 at 8:15 PM Vasily Gorbik <g...@linux.ibm.com> wrote:
> Commit be83bbf80682 ("mmap: introduce sane default mmap limits")
> introduced "pgoff" limits checks for mmap, considering fs max file size
> as upper limit, which made it impossible to mmap /proc/vmcore file
> contents above 2Gb (/proc/vmcore appears to be the only procfs file
> supporting mmap).
> Reuse MAX_LFS_FILESIZE as procfs s_maxbytes value.
Ugh. /proc is where a lot of problems *have* been.
Admittedly not as much as random drivers, but still. If proc doesn't set
s_maxbytes, then we should not raise it here magically, there might be
various /proc files that get offset accounting wrong.
I'd *much* rather just set FMODE_UNSIGNED_OFFSET for /proc/vmcore _only_,
rather than open up all proc files to issues with 4G+ offsets.
Linus
