From: Pavel Tatashin <pasha.tatashin@soleen.com>
Date: Fri, 19 Mar 2021 20:50:54 +0000 (-0400)
Subject: arm64: kdump: update ppos when reading elfcorehdr
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=141f8202cfa4192c3af79b6cbd68e7760bb01b5a;p=linux.git

arm64: kdump: update ppos when reading elfcorehdr

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>
---

diff --git a/arch/arm64/kernel/crash_dump.c b/arch/arm64/kernel/crash_dump.c
index e6e284265f19d..58303a9ec32c4 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;
 }