From: Pavel Tatashin <pasha.tatashin@soleen.com>

Date: Fri, 19 Mar 2021 16:50:54 -0400

Subject: arm64: kdump: update ppos when reading elfcorehdr

Git-commit: 141f8202cfa4192c3af79b6cbd68e7760bb01b5a

Patch-mainline: v5.12-rc5

References: git-fixes

The ppos points to a position in the old kernel memory (and in case of

arm64 in the crash kernel since elfcorehdr is passed as a segment). The

function should update the ppos by the amount that was read. This bug is

not exposed by accident, but other platforms update this value properly.

So, fix it in ARM64 version of elfcorehdr_read() as well.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>

Fixes: e62aaeac426a ("arm64: kdump: provide /proc/vmcore file")

Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>

Link: https://lore.kernel.org/r/20210319205054.743368-1-pasha.tatashin@soleen.com

Signed-off-by: Will Deacon <will@kernel.org>

Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>

---

 arch/arm64/kernel/crash_dump.c | 2 ++

 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/kernel/crash_dump.c b/arch/arm64/kernel/crash_dump.c

index e6e284265f19..58303a9ec32c 100644

--- a/arch/arm64/kernel/crash_dump.c

+++ b/arch/arm64/kernel/crash_dump.c

@@ -64,5 +64,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,

 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)

 {

 	memcpy(buf, phys_to_virt((phys_addr_t)*ppos), count);

+	*ppos += count;

+

 	return count;

 }

-- 

2.26.2