20e55bc17d
set_pmd_at() calls native_set_pmd() unconditionally on x86. This was fine as long as only huge page entries were written via set_pmd_at(), as Xen pv guests don't support those. Commit2c91bd4a4e("mm: speed up mremap by 20x on large regions") introduced a usage of set_pmd_at() possible on pv guests, leading to failures like: BUG: unable to handle kernel paging request at ffff888023e26778 #PF error: [PROT] [WRITE] RIP: e030:move_page_tables+0x7c1/0xae0 move_vma.isra.3+0xd1/0x2d0 __se_sys_mremap+0x3c6/0x5b0 do_syscall_64+0x49/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Make set_pmd_at() paravirt aware by just letting it use set_pmd(). Fixes:2c91bd4a4e("mm: speed up mremap by 20x on large regions") Reported-by: Sander Eikelenboom <linux@eikelenboom.it> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: xen-devel@lists.xenproject.org Cc: boris.ostrovsky@oracle.com Cc: sstabellini@kernel.org Cc: hpa@zytor.com Cc: bp@alien8.de Cc: torvalds@linux-foundation.org Link: https://lkml.kernel.org/r/20190210074056.11842-1-jgross@suse.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.