From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
naveen.n.rao@linux.vnet.ibm.com
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [PATCH] powerpc/kprobes: Use probe_address() to read instructions
Date: Mon, 24 Feb 2020 18:02:10 +0000 (UTC) [thread overview]
Message-ID: <7f24b5961a6839ff01df792816807f74ff236bf6.1582567319.git.christophe.leroy@c-s.fr> (raw)
In order to avoid Oopses, use probe_address() to read the
instruction at the address where the trap happened.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/kernel/kprobes.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 84567406b53d..a35320b79e16 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -276,14 +276,18 @@ int kprobe_handler(struct pt_regs *regs)
p = get_kprobe(addr);
if (!p) {
- if (*addr != BREAKPOINT_INSTRUCTION) {
+ unsigned int instr;
+
+ if (probe_kernel_address(addr, instr))
+ goto no_kprobe;
+
+ if (instr != BREAKPOINT_INSTRUCTION) {
/*
* PowerPC has multiple variants of the "trap"
* instruction. If the current instruction is a
* trap variant, it could belong to someone else
*/
- kprobe_opcode_t cur_insn = *addr;
- if (is_trap(cur_insn))
+ if (is_trap(instr))
goto no_kprobe;
/*
* The breakpoint instruction was removed right
--
2.25.0
next reply other threads:[~2020-02-24 18:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-24 18:02 Christophe Leroy [this message]
2020-06-09 5:28 ` [PATCH] powerpc/kprobes: Use probe_address() to read instructions Michael Ellerman
2020-06-09 5:53 ` Christoph Hellwig
2020-06-10 10:12 ` Michael Ellerman
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=7f24b5961a6839ff01df792816807f74ff236bf6.1582567319.git.christophe.leroy@c-s.fr \
--to=christophe.leroy@c-s.fr \
--cc=benh@kernel.crashing.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=naveen.n.rao@linux.vnet.ibm.com \
--cc=paulus@samba.org \
/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).