Re: [PATCH 32/35] kasan, arm64: print report from tag fault handler
From: Vincenzo Frascino <vincenzo.frascino@arm.com>
Date: 2020-08-27 12:34:39
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linux-mm, lkml
On 8/27/20 11:48 AM, Catalin Marinas wrote:
On Fri, Aug 14, 2020 at 07:27:14PM +0200, Andrey Konovalov wrote:quoted
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index c62c8ba85c0e..cf00b3942564 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>@@ -314,11 +315,19 @@ static void report_tag_fault(unsigned long addr, unsigned int esr, { bool is_write = ((esr & ESR_ELx_WNR) >> ESR_ELx_WNR_SHIFT) != 0; +#ifdef CONFIG_KASAN_HW_TAGS + /* + * 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 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)); +#endif }More dead code. So what's the point of keeping the pr_alert() introduced earlier? CONFIG_KASAN_HW_TAGS is always on for in-kernel MTE. If MTE is disabled, this function isn't called anyway.
I agree we should remove them (togheter with '#ifdef CONFIG_KASAN_HW_TAGS') or integrate them with the kasan code if still meaningful. -- Regards, Vincenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel