Thread (90 messages) 90 messages, 5 authors, 2020-09-24

Re: [PATCH v2 34/37] kasan, arm64: print report from tag fault handler

From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2020-09-17 18:38:01
Also in: linux-mm, lkml

On Tue, Sep 15, 2020 at 11:16:16PM +0200, Andrey Konovalov wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index cdc23662691c..ac79819317f2 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -14,6 +14,7 @@
 #include <linux/mm.h>
 #include <linux/hardirq.h>
 #include <linux/init.h>
+#include <linux/kasan.h>
 #include <linux/kprobes.h>
 #include <linux/uaccess.h>
 #include <linux/page-flags.h>
@@ -295,17 +296,23 @@ static void die_kernel_fault(const char *msg, unsigned long addr,
 	do_exit(SIGKILL);
 }
 
+#ifdef CONFIG_KASAN_HW_TAGS
 static void report_tag_fault(unsigned long addr, unsigned int esr,
 			     struct pt_regs *regs)
 {
-	bool is_write = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0;
+	bool is_write  = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0;
 
-	pr_alert("Memory Tagging Extension Fault in %pS\n", (void *)regs->pc);
-	pr_alert("  %s at address %lx\n", is_write ? "Write" : "Read", addr);
-	pr_alert("  Pointer tag: [%02x], memory tag: [%02x]\n",
-			mte_get_ptr_tag(addr),
-			mte_get_mem_tag((void *)addr));
+	/*
+	 * SAS bits aren't set for all faults reported in EL1, so we can't
+	 * find out access size.
+	 */
+	kasan_report(addr, 0, is_write, regs->pc);
 }
+#else
+/* Tag faults aren't enabled without CONFIG_KASAN_HW_TAGS. */
+static inline void report_tag_fault(unsigned long addr, unsigned int esr,
+				    struct pt_regs *regs) { }
+#endif
So is there a point in introducing this function in an earlier patch,
just to remove its content here?

-- 
Catalin

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