x86/hpet: Prevent potential NULL pointer dereference

Aditya Pakki · KAGA-KOKO · commit 2e84f116afca · 2019-03-21T12:24:38.000+01:00
hpet_virt_address may be NULL when ioremap_nocache fail, but the code lacks a check. Add a check to prevent NULL pointer dereference. Signed-off-by: Aditya Pakki <pakki001@umn.edu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: kjlu@umn.edu Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Joe Perches <joe@perches.com> Cc: Nicolai Stange <nstange@suse.de> Cc: Roland Dreier <roland@purestorage.com> Link: https://lkml.kernel.org/r/20190319021958.17275-1-pakki001@umn.edu
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
@@ -905,6 +905,8 @@ int __init hpet_enable(void)
 		return 0;
 
 	hpet_set_mapping();
+	if (!hpet_virt_address)
+		return 0;
 
 	/*
 	 * Read the period and check for a sane value:
