From: Steven Price <steven.price@xxxxxxx>
Subject: initramfs: don't free a non-existent initrd
Since 54c7a8916a88 ("initramfs: free initrd memory if opening
/initrd.image fails"), the kernel has unconditionally attempted to free
the initrd even if it doesn't exist. In the non-existent case this causes
a boot-time splat if CONFIG_DEBUG_VIRTUAL is enabled due to a call to
virt_to_phys() with a NULL address.
Instead we should check that the initrd actually exists and only attempt
to free it if it does.
Link: http://lkml.kernel.org/r/20190516143125.48948-1-steven.price@xxxxxxx
Fixes: 54c7a8916a88 ("initramfs: free initrd memory if opening /initrd.image fails")
Signed-off-by: Steven Price <steven.price@xxxxxxx>
Reported-by: Mark Rutland <mark.rutland@xxxxxxx>
Tested-by: Mark Rutland <mark.rutland@xxxxxxx>
Reviewed-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
init/initramfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/init/initramfs.c~initramfs-dont-free-a-non-existent-initrd
+++ a/init/initramfs.c
@@ -669,7 +669,7 @@ done:
* If the initrd region is overlapped with crashkernel reserved region,
* free only memory that is not part of crashkernel region.
*/
- if (!do_retain_initrd && !kexec_free_initrd())
+ if (!do_retain_initrd && initrd_start && !kexec_free_initrd())
free_initrd_mem(initrd_start, initrd_end);
initrd_start = 0;
initrd_end = 0;
_
