diff mbox series

[v2,3/6] x86/mce: Fix use of uninitialized MCE message string

Message ID 20200103150722.20313-4-jschoenh@amazon.de (mailing list archive)
State New, archived
Headers show
Series x86/mce: Various fixes and cleanups for MCE handling | expand

Commit Message

Jan H. Schönherr Jan. 3, 2020, 3:07 p.m. UTC
The function mce_severity() is not required to update its msg argument.
In fact, mce_severity_amd() does not, which makes mce_no_way_out()
return uninitialized data, which may be used later for printing.

Assuming that implementations of mce_severity() either always or never
update the msg argument (which is currently the case), it is sufficient
to initialize the temporary variable in mce_no_way_out().

While at it, avoid printing a useless "Unknown".

Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
---
Changes v1->v2:
- simplify fix by assuming that mce_severity() either always or never
  updates the msg argument -- as opposed to mce_severity() having the
  freedom to decide on a case by case basis (requested by Boris);
- stop printing "Unknown" (requested by Boris).
---
 arch/x86/kernel/cpu/mce/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 0ccd6cf3402d..1d91ce956772 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -790,7 +790,7 @@  EXPORT_SYMBOL_GPL(machine_check_poll);
 static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp,
 			  struct pt_regs *regs)
 {
-	char *tmp;
+	char *tmp = *msg;
 	int i;
 
 	for (i = 0; i < this_cpu_read(mce_num_banks); i++) {
@@ -1209,8 +1209,8 @@  void do_machine_check(struct pt_regs *regs, long error_code)
 	DECLARE_BITMAP(toclear, MAX_NR_BANKS);
 	struct mca_config *cfg = &mca_cfg;
 	int cpu = smp_processor_id();
-	char *msg = "Unknown";
 	struct mce m, *final;
+	char *msg = NULL;
 	int worst = 0;
 
 	/*