From: Florian Fainelli <f.fainelli@gmail.com>
To: linux-arm-kernel@lists.infradead.org
Cc: andrew@lunn.ch, Florian Fainelli <f.fainelli@gmail.com>,
Russell King <linux@armlinux.org.uk>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Tony Lindgren <tony@atomide.com>,
Souptick Joarder <jrdr.linux@gmail.com>,
linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] ARM: mm: Facilitate debugging CONFIG_KUSER_HELPERS disabled
Date: Thu, 25 Oct 2018 11:09:55 -0700 [thread overview]
Message-ID: <20181025180957.7900-1-f.fainelli@gmail.com> (raw)
Some software such as perf makes unconditional use of the special
[vectors] page which is only provided when CONFIG_KUSER_HELPERS is
enabled in the kernel.
Facilitate the debugging of such situations by printing a debug message
to the kernel log showing the task name and the faulting address.
Suggested-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
arch/arm/mm/fault.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index f4ea4c62c613..f17471fbc1c4 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -173,6 +173,11 @@ __do_user_fault(struct task_struct *tsk, unsigned long addr,
show_regs(regs);
}
#endif
+#ifndef CONFIG_KUSER_HELPERS
+ if ((sig == SIGSEGV) && ((addr & PAGE_MASK) == 0xffff0000))
+ printk(KERN_DEBUG "%s: CONFIG_KUSER_HELPERS disabled at 0x%08lx\n",
+ tsk->comm, addr);
+#endif
tsk->thread.address = addr;
tsk->thread.error_code = fsr;
--
2.17.1
next reply other threads:[~2018-10-25 18:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-25 18:09 Florian Fainelli [this message]
2018-10-25 18:25 ` [PATCH] ARM: mm: Facilitate debugging CONFIG_KUSER_HELPERS disabled Eric W. Biederman
2018-10-25 18:50 ` Florian Fainelli
2018-10-25 18:30 ` Souptick Joarder
2018-10-25 18:48 ` Florian Fainelli
2018-10-25 19:06 ` Souptick Joarder
2018-10-25 21:20 ` Russell King - ARM Linux
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181025180957.7900-1-f.fainelli@gmail.com \
--to=f.fainelli@gmail.com \
--cc=andrew@lunn.ch \
--cc=ebiederm@xmission.com \
--cc=jrdr.linux@gmail.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=tony@atomide.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).