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efi/cper: use stack buffer for error record decoding

PATCH New Ard Biesheuvel 1 participant 1 message Sep 1, 2021

Subsystems (3)
Stable branch EFI ACPI APEI
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Ard Biesheuvel

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PATCH 1/1 efi/cper: use stack buffer for error record decoding

Joe reports that using a statically allocated buffer for converting CPER error records into human readable text is probably a bad idea. Even though we are not aware of any actual issues, a stack buffer is clearly a better choice here anyway, so let's move the buffer into the stack frames of the two functions that refer to it.

Cc <[email protected]>
Reported-by Joe Perches <[email protected]>
Signed-off-by Ard Biesheuvel <[email protected]>
---
 drivers/firmware/efi/cper.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/firmware/efi/cper.c +2 -2
index 73bdbd207e7a..6ec8edec6329 100644
@@ -25,8 +25,6 @@
 #include <acpi/ghes.h>
 #include <ras/ras_event.h>
 
-static char rcd_decode_str[CPER_REC_LEN];
-
 /*
  * CPER record ID need to be unique even after reboot, because record
  * ID is used as index for ERST storage, while CPER records from

@@ -312,6 +310,7 @@ const char *cper_mem_err_unpack(struct trace_seq *p,
 				struct cper_mem_err_compact *cmem)
 {
 	const char *ret = trace_seq_buffer_ptr(p);
+	char rcd_decode_str[CPER_REC_LEN];
 
 	if (cper_mem_err_location(cmem, rcd_decode_str))
 		trace_seq_printf(p, "%s", rcd_decode_str);

@@ -326,6 +325,7 @@ static void cper_print_mem(const char *pfx, const struct cper_sec_mem_err *mem,
 	int len)
 {
 	struct cper_mem_err_compact cmem;
+	char rcd_decode_str[CPER_REC_LEN];
 
 	/* Don't trust UEFI 2.1/2.2 structure with bad validation bits */
 	if (len == sizeof(struct cper_sec_mem_err_old) &&
Signature · 1 line
2.30.2