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Peter Anvin" , x86@kernel.org Subject: [PATCH v2 3/6] x86/mce: Fix use of uninitialized MCE message string Date: Fri, 3 Jan 2020 16:07:19 +0100 Message-Id: <20200103150722.20313-4-jschoenh@amazon.de> X-Mailer: git-send-email 2.22.0.3.gb49bb57c8208.dirty In-Reply-To: <20200103150722.20313-1-jschoenh@amazon.de> References: <20200103150722.20313-1-jschoenh@amazon.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 --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; /* -- 2.22.0.3.gb49bb57c8208.dirty