6.18-stable review patch. If anyone has any objections, please let me know.
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From: Pingfan Liu piliu@redhat.com
commit a3785ae5d334bb71d47a593d54c686a03fb9d136 upstream.
*** Bug description ***
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 ]---
*** How to reproduce ***
This bug is only triggered when the kexec target address is allocated in the CMA area. If no CMA area is reserved in the kernel, use the "cma=" option in the kernel command line to reserve one.
*** Root cause *** The commit 07d24902977e ("kexec: enable CMA based contiguous allocation") allocates the kexec target address directly on the CMA area to avoid copying during the jump. In this case, there is no IND_SOURCE for the kexec segment. But the current implementation of kimage_map_segment() assumes that IND_SOURCE pages exist and map them into a contiguous virtual address by vmap().
*** Solution *** If IMA segment is allocated in the CMA area, use its page_address() directly.
Link: https://lkml.kernel.org/r/20251216014852.8737-2-piliu@redhat.com Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation") Signed-off-by: Pingfan Liu piliu@redhat.com Acked-by: Baoquan He bhe@redhat.com Cc: Alexander Graf graf@amazon.com Cc: Steven Chen chenste@linux.microsoft.com Cc: Mimi Zohar zohar@linux.ibm.com Cc: Roberto Sassu roberto.sassu@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/kexec_core.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
--- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -967,13 +967,17 @@ void *kimage_map_segment(struct kimage * kimage_entry_t *ptr, entry; struct page **src_pages; unsigned int npages; + struct page *cma; void *vaddr = NULL; int i;
+ cma = image->segment_cma[idx]; + if (cma) + return page_address(cma); + 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. */ @@ -1014,7 +1018,8 @@ void *kimage_map_segment(struct kimage *
void kimage_unmap_segment(void *segment_buffer) { - vunmap(segment_buffer); + if (is_vmalloc_addr(segment_buffer)) + vunmap(segment_buffer); }
struct kexec_load_limit {