*** 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.
Fixes: 07d24902977e ("kexec: enable CMA based contiguous allocation")
Signed-off-by: Pingfan Liu <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: Alexander Graf <[email protected]>
Cc: Steven Chen <[email protected]>
Cc: Mimi Zohar <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: <[email protected]>
To: [email protected]
---
v2 -> v3
improve commit log
kernel/kexec_core.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 1a79c5b18d8f..95c585c6ddc3 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -960,13 +960,17 @@ 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;
+ 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.
*/
@@ -1007,7 +1011,8 @@ 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
