Re: [PATCHv2 1/2] kernel/kexec: Change the prototype of kimage_map_segment()

[Baoquan He <bhe@redhat.com>]

On 11/24/25 at 02:16pm, Andrew Morton wrote:
> On Thu,  6 Nov 2025 14:59:03 +0800 Pingfan Liu <piliu@redhat.com> wrote:
> 
> > The kexec segment index will be required to extract the corresponding
> > information for that segment in kimage_map_segment(). Additionally,
> > kexec_segment already holds the kexec relocation destination address and
> > size. Therefore, the prototype of kimage_map_segment() can be changed.
> 
> Could we please have some reviewer input on thee two patches?

I have some concerns about the one place of tiny code change, and the
root cause missing in log. And Mimi sent mail to me asking why this bug
can'e be seen on her laptop, I told her this bug can only be triggered
on system where CMA area exists. I think these need be addressed in v3.

> 
> (Pingfan, please cc linux-kernel on patches - it's where people go to
> find emails on lists which they aren't suscribed to)
> 
> (akpm goes off and subscribes to kexec@)
> 
> > 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: Mimi Zohar <zohar@linux.ibm.com>
> > Cc: Roberto Sassu <roberto.sassu@huawei.com>
> > Cc: Alexander Graf <graf@amazon.com>
> > Cc: Steven Chen <chenste@linux.microsoft.com>
> > Cc: <stable@vger.kernel.org>
> > To: kexec@lists.infradead.org
> > To: linux-integrity@vger.kernel.org
> > ---
> >  include/linux/kexec.h              | 4 ++--
> >  kernel/kexec_core.c                | 9 ++++++---
> >  security/integrity/ima/ima_kexec.c | 4 +---
> >  3 files changed, 9 insertions(+), 8 deletions(-)
> > 
> > diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> > index ff7e231b0485..8a22bc9b8c6c 100644
> > --- a/include/linux/kexec.h
> > +++ b/include/linux/kexec.h
> > @@ -530,7 +530,7 @@ extern bool kexec_file_dbg_print;
> >  #define kexec_dprintk(fmt, arg...) \
> >          do { if (kexec_file_dbg_print) pr_info(fmt, ##arg); } while (0)
> >  
> > -extern void *kimage_map_segment(struct kimage *image, unsigned long addr, unsigned long size);
> > +extern void *kimage_map_segment(struct kimage *image, int idx);
> >  extern void kimage_unmap_segment(void *buffer);
> >  #else /* !CONFIG_KEXEC_CORE */
> >  struct pt_regs;
> > @@ -540,7 +540,7 @@ static inline void __crash_kexec(struct pt_regs *regs) { }
> >  static inline void crash_kexec(struct pt_regs *regs) { }
> >  static inline int kexec_should_crash(struct task_struct *p) { return 0; }
> >  static inline int kexec_crash_loaded(void) { return 0; }
> > -static inline void *kimage_map_segment(struct kimage *image, unsigned long addr, unsigned long size)
> > +static inline void *kimage_map_segment(struct kimage *image, int idx)
> >  { return NULL; }
> >  static inline void kimage_unmap_segment(void *buffer) { }
> >  #define kexec_in_progress false
> > diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> > index fa00b239c5d9..9a1966207041 100644
> > --- a/kernel/kexec_core.c
> > +++ b/kernel/kexec_core.c
> > @@ -960,17 +960,20 @@ int kimage_load_segment(struct kimage *image, int idx)
> >  	return result;
> >  }
> >  
> > -void *kimage_map_segment(struct kimage *image,
> > -			 unsigned long addr, unsigned long size)
> > +void *kimage_map_segment(struct kimage *image, int idx)
> >  {
> > +	unsigned long addr, size, eaddr;
> >  	unsigned long src_page_addr, dest_page_addr = 0;
> > -	unsigned long eaddr = addr + size;
> >  	kimage_entry_t *ptr, entry;
> >  	struct page **src_pages;
> >  	unsigned int npages;
> >  	void *vaddr = NULL;
> >  	int i;
> >  
> > +	addr = image->segment[idx].mem;
> > +	size = image->segment[idx].memsz;
> > +	eaddr = addr + size;
> > +
> >  	/*
> >  	 * Collect the source pages and map them in a contiguous VA range.
> >  	 */
> > diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
> > index 7362f68f2d8b..5beb69edd12f 100644
> > --- a/security/integrity/ima/ima_kexec.c
> > +++ b/security/integrity/ima/ima_kexec.c
> > @@ -250,9 +250,7 @@ void ima_kexec_post_load(struct kimage *image)
> >  	if (!image->ima_buffer_addr)
> >  		return;
> >  
> > -	ima_kexec_buffer = kimage_map_segment(image,
> > -					      image->ima_buffer_addr,
> > -					      image->ima_buffer_size);
> > +	ima_kexec_buffer = kimage_map_segment(image, image->ima_segment_index);
> >  	if (!ima_kexec_buffer) {
> >  		pr_err("Could not map measurements buffer.\n");
> >  		return;
> > -- 
> > 2.49.0
>