Re: [PATCHv2 2/2] kernel/kexec: Fix IMA when allocation happens in CMA area

Pingfan Liu
2025-11-06T10:02:04Z

On Thu, Nov 6, 2025 at 4:01 PM Baoquan He <bhe@redhat.com> wrote:
>
> On 11/06/25 at 02:59pm, Pingfan Liu wrote:
> > When I tested kexec with the latest kernel, I ran into the following warning:
> >
> > [ 40.712410] ------------[ cut here ]------------
> > [ 40.712576] WARNING: CPU: 2 PID: 1562 at kernel/kexec_core.c:1001 kimage_map_segment+0x144/0x198
> > [...]
> > [ 40.816047] Call trace:
> > [ 40.818498] kimage_map_segment+0x144/0x198 (P)
> > [ 40.823221] ima_kexec_post_load+0x58/0xc0
> > [ 40.827246] __do_sys_kexec_file_load+0x29c/0x368
> > [...]
> > [ 40.855423] ---[ end trace 0000000000000000 ]---
> >
> > This is caused by the fact that kexec allocates the destination directly
> > in the CMA area. In that case, the CMA kernel address should be exported
> > directly to the IMA component, instead of using the vmalloc'd address.
>
> Well, you didn't update the log accordingly.
>

I am not sure what you mean. Do you mean the earlier content which I
replied to you?

> Do you know why cma area can't be mapped into vmalloc?
>
Should not the kernel direct mapping be used?

Thanks,

Pingfan
> >
> > Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
> > Signed-off-by: Pingfan Liu <piliu@redhat.com>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: Baoquan He <bhe@redhat.com>
> > Cc: Alexander Graf <graf@amazon.com>
> > Cc: Steven Chen <chenste@linux.microsoft.com>
> > Cc: linux-integrity@vger.kernel.org
> > Cc: <stable@vger.kernel.org>
> > To: kexec@lists.infradead.org
> > ---
> > v1 -> v2:
> > return page_address(page) instead of *page
> >
> > kernel/kexec_core.c | 7 ++++++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> > index 9a1966207041..332204204e53 100644
> > --- a/kernel/kexec_core.c
> > +++ b/kernel/kexec_core.c
> > @@ -967,6 +967,7 @@ void *kimage_map_segment(struct kimage *image, int idx)
> > kimage_entry_t *ptr, entry;
> > struct page **src_pages;
> > unsigned int npages;
> > + struct page *cma;
> > void *vaddr = NULL;
> > int i;
> >
> > @@ -974,6 +975,9 @@ void *kimage_map_segment(struct kimage *image, int idx)
> > size = image->segment[idx].memsz;
> > eaddr = addr + size;
> >
> > + cma = image->segment_cma[idx];
> > + if (cma)
> > + return page_address(cma);
> > /*
> > * Collect the source pages and map them in a contiguous VA range.
> > */
> > @@ -1014,7 +1018,8 @@ void *kimage_map_segment(struct kimage *image, int idx)
> >
> > void kimage_unmap_segment(void *segment_buffer)
> > {
> > - vunmap(segment_buffer);
> > + if (is_vmalloc_addr(segment_buffer))
> > + vunmap(segment_buffer);
> > }
> >
> > struct kexec_load_limit {
> > --
> > 2.49.0
> >
>