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From:   Kefeng Wang <wangkefeng.wang@huawei.com>
To:     Russell King <linux@armlinux.org.uk>
CC:     <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>,
        Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: [PATCH v3] ARM: mm: Provide better message when kernel fault
Date:   Tue, 27 Sep 2022 14:21:34 +0800
Message-ID: <20220927062134.99019-1-wangkefeng.wang@huawei.com>
In-Reply-To: <YzF7X2PBdps2MaG/@shell.armlinux.org.uk>
References: <YzF7X2PBdps2MaG/@shell.armlinux.org.uk>
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If there is a kernel fault, see do_kernel_fault(), we only print
the generic "paging request" or "NULL pointer dereference" message
which don't show read, write or excute information, let's provide
better fault message for them.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
v3: show the infos in die_kernel_fault()
 arch/arm/mm/fault.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 46cccd6bf705..f8fe0ec64c23 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -111,8 +111,9 @@ static void die_kernel_fault(const char *msg, struct mm_struct *mm,
 {
 	bust_spinlocks(1);
 	pr_alert("8<--- cut here ---\n");
-	pr_alert("Unable to handle kernel %s at virtual address %08lx\n",
-		 msg, addr);
+	pr_alert("Unable to handle kernel %s at virtual address %08lx when %s\n",
+		 msg, addr, fsr & FSR_LNX_PF ? "execute" :
+		 fsr & FSR_WRITE ? "write" : "read");
 
 	show_pte(KERN_ALERT, mm, addr);
 	die("Oops", regs, fsr);
-- 
2.35.3