[Bug runtime/30617] New: Systemtap unable to successfully build kernel modules linux-6.5

[Bug runtime/30617] New: Systemtap unable to successfully build kernel modules linux-6.5

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30617

            Bug ID: 30617
           Summary: Systemtap unable to successfully build kernel modules
                    linux-6.5
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: runtime
          Assignee: systemtap at sourceware dot org
          Reporter: wcohen at redhat dot com
  Target Milestone: ---

Fedora rawhide recently switched to the linux-6.5 kernels.  Systemtap from the
git repo works with the earlier linux-6.4, but when attempting to run any
systemtap instrumentation on linux-6.5 the build fails.  This can be seen with
"make installcheck" the smoke test will fail with the following messages.  


In file included from
/home/wcohen/systemtap_write/install/share/systemtap/runtime/linux/runtime.h:271,
                 from
/home/wcohen/systemtap_write/install/share/systemtap/runtime/runtime.h:26,
                 from
/tmp/stapndYBKY/stap_34ef71e6e2ed0e338834720b8dff538e_1736_src.c:21:
/home/wcohen/systemtap_write/install/share/systemtap/runtime/linux/access_process_vm.h:
In function '__access_process_vm_':
/home/wcohen/systemtap_write/install/share/systemtap/runtime/linux/access_process_vm.h:57:36:
error: passing argument 1 of 'get_user_pages_remote' from incompatible pointer
type [-Werror=incompatible-pointer-types]
   57 |       ret = get_user_pages_remote (tsk, mm, addr, 1, write, 1, &page,
&vma);
      |                                    ^~~
      |                                    |
      |                                    struct task_struct *
In file included from ./include/linux/kallsyms.h:13,
                 from ./include/linux/ftrace.h:13,
                 from ./include/linux/kprobes.h:28,
                 from
/home/wcohen/systemtap_write/install/share/systemtap/runtime/linux/runtime.h:21:
./include/linux/mm.h:2377:46: note: expected 'struct mm_struct *' but argument
is of type 'struct task_struct *'
 2377 | long get_user_pages_remote(struct mm_struct *mm,
      |                            ~~~~~~~~~~~~~~~~~~^~
/home/wcohen/systemtap_write/install/share/systemtap/runtime/linux/access_process_vm.h:57:41:
error: passing argument 2 of 'get_user_pages_remote' makes integer from pointer
without a cast [-Werror=int-conversion]
   57 |       ret = get_user_pages_remote (tsk, mm, addr, 1, write, 1, &page,
&vma);
      |                                         ^~
      |                                         |
      |                                         struct mm_struct *
./include/linux/mm.h:2378:42: note: expected 'long unsigned int' but argument
is of type 'struct mm_struct *'
 2378 |                            unsigned long start, unsigned long nr_pages,
      |                            ~~~~~~~~~~~~~~^~~~~
/home/wcohen/systemtap_write/install/share/systemtap/runtime/linux/access_process_vm.h:57:54:
error: passing argument 5 of 'get_user_pages_remote' makes pointer from integer
without a cast [-Werror=int-conversion]
   57 |       ret = get_user_pages_remote (tsk, mm, addr, 1, write, 1, &page,
&vma);
      |                                                      ^~~~~
      |                                                      |
      |                                                      int
./include/linux/mm.h:2379:66: note: expected 'struct page **' but argument is
of type 'int'
 2379 |                            unsigned int gup_flags, struct page **pages,
      |                                                    ~~~~~~~~~~~~~~^~~~~
/home/wcohen/systemtap_write/install/share/systemtap/runtime/linux/access_process_vm.h:57:61:
error: passing argument 6 of 'get_user_pages_remote' makes pointer from integer
without a cast [-Werror=int-conversion]
   57 |       ret = get_user_pages_remote (tsk, mm, addr, 1, write, 1, &page,
&vma);
      |                                                             ^
      |                                                             |
      |                                                             int
./include/linux/mm.h:2380:33: note: expected 'int *' but argument is of type
'int'
 2380 |                            int *locked);
      |                            ~~~~~^~~~~~
/home/wcohen/systemtap_write/install/share/systemtap/runtime/linux/access_process_vm.h:57:13:
error: too many arguments to function 'get_user_pages_remote'
   57 |       ret = get_user_pages_remote (tsk, mm, addr, 1, write, 1, &page,
&vma);
      |             ^~~~~~~~~~~~~~~~~~~~~
./include/linux/mm.h:2377:6: note: declared here
 2377 | long get_user_pages_remote(struct mm_struct *mm,
      |      ^~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
make[4]: *** [scripts/Makefile.build:252:
/tmp/stapndYBKY/stap_34ef71e6e2ed0e338834720b8dff538e_1736_src.o] Error 1
make[3]: *** [Makefile:2050: /tmp/stapndYBKY] Error 2
WARNING: kbuild exited with status: 2
Pass 4: compilation failed.  [man error::pass4]
child process exited abnormally

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[Bug runtime/30617] Systemtap unable to successfully build kernel modules for linux-6.5

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30617

William Cohen <wcohen at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Systemtap unable to         |Systemtap unable to
                   |successfully build kernel   |successfully build kernel
                   |modules linux-6.5           |modules for linux-6.5

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[Bug runtime/30617] Systemtap unable to successfully build kernel modules for linux-6.5

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30617

William Cohen <wcohen at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED

--- Comment #1 from William Cohen <wcohen at redhat dot com> ---
Found that the specific upstream linux kernel git commit causing the issue is:

commit ca5e863233e8f6acd1792fd85d6bc2729a1b2c10
Author: Lorenzo Stoakes <lstoakes@gmail.com>
Date:   Wed May 17 20:25:39 2023 +0100

    mm/gup: remove vmas parameter from get_user_pages_remote()

    The only instances of get_user_pages_remote() invocations which used the
    vmas parameter were for a single page which can instead simply look up the
    VMA directly. In particular:-

    - __update_ref_ctr() looked up the VMA but did nothing with it so we simply
      remove it.

    - __access_remote_vm() was already using vma_lookup() when the original
      lookup failed so by doing the lookup directly this also de-duplicates the
      code.

    We are able to perform these VMA operations as we already hold the
    mmap_lock in order to be able to call get_user_pages_remote().

    As part of this work we add get_user_page_vma_remote() which abstracts the
    VMA lookup, error handling and decrementing the page reference count should
    the VMA lookup fail.

    This forms part of a broader set of patches intended to eliminate the vmas
    parameter altogether.

    [akpm@linux-foundation.org: avoid passing NULL to PTR_ERR]
    Link:
https://lkml.kernel.org/r/d20128c849ecdbf4dd01cc828fcec32127ed939a.1684350871.git.lstoakes@gmail.com
    Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
    Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> (for arm64)
    Acked-by: David Hildenbrand <david@redhat.com>
    Reviewed-by: Janosch Frank <frankja@linux.ibm.com> (for s390)
    Reviewed-by: Christoph Hellwig <hch@lst.de>
    Cc: Christian König <christian.koenig@amd.com>
    Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Cc: Jarkko Sakkinen <jarkko@kernel.org>
    Cc: Jason Gunthorpe <jgg@nvidia.com>
    Cc: Jens Axboe <axboe@kernel.dk>
    Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
    Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
    Cc: Sean Christopherson <seanjc@google.com>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>


The vma argument is dropped from get_user_pages_remote() and a
get_user_page_vma_remote() should be used in situations where vma being passed
into get_user_pages_remote() is non-NULL.

The plan of action to fix this is to check for get_user_page_vma_remote() as a
autoconf test and then use it in the systemtap runtime if it is available.

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[Bug runtime/30617] Systemtap unable to successfully build kernel modules for linux-6.5

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30617

--- Comment #2 from William Cohen <wcohen at redhat dot com> ---
Created attachment 14958
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14958&action=edit
Patch to use new get_user_page_vma_remote function in linux 6.5

This patch allows things to compile on rawhide linux 6.5 kernel.  It also
allows things to still build on RHEL 8 and 9.  However, need to test that the
functionality for userspace access via __access_process_vm_ works.

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You are receiving this mail because:
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[Bug runtime/30617] Systemtap unable to successfully build kernel modules for linux-6.5

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30617

William Cohen <wcohen at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #3 from William Cohen <wcohen at redhat dot com> ---
Following test provided reasonable results on Fedora rawhide and RHEL8:

sudo ../install/bin/stap --example para-callgraph.stp
'process("/usr/bin/ls").function("*")' -c /usr/bin/ls

The following also produced reasonable results on Fedora rawhide and RHEL8:

 sudo ../install/bin/stap --example glibc-malloc.stp -c 'stap --dump-functions'


The patch is in the master branch as:

commit e891a37e366362a12ca311439918d69ffe641cec (HEAD -> master, origin/master,
origin/HEAD)
Author: William Cohen <wcohen@redhat.com>
Date:   Sun Jul 9 16:46:20 2023 -0400

    Adjust runtime _access_process_vm_ to work with linux 6.5

    Linux kernel commit ca5e863233e8f6acd1792fd85d6bc2729a1b2c10
    eliminated the vma argument for ‘get_user_pages_remote.  For linux 6.5
    kernel use the get_user_page_vma_remote function in its place like the
    __access_remote_vm function in mm/memory.c of the kernel.

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