Commit 7a8bc2b0 authored Jan 03, 2020 by Jan H. Schönherr Committed by Borislav Petkov Jan 13, 2020

x86/mce: Fix use of uninitialized MCE message string

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>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200103150722.20313-4-jschoenh@amazon.de

parent 90454e49

arch/x86/kernel/cpu/mce/core.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -795,7 +795,7 @@ 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++) {
		@@ -1220,8 +1220,8 @@ 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;

		/*

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