* [PATCH] powerpc/kprobes: Use probe_address() to read instructions
@ 2020-02-24 18:02 Christophe Leroy
2020-06-09 5:28 ` Michael Ellerman
0 siblings, 1 reply; 4+ messages in thread
From: Christophe Leroy @ 2020-02-24 18:02 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
naveen.n.rao
Cc: linuxppc-dev, linux-kernel
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
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] powerpc/kprobes: Use probe_address() to read instructions
2020-02-24 18:02 [PATCH] powerpc/kprobes: Use probe_address() to read instructions Christophe Leroy
@ 2020-06-09 5:28 ` Michael Ellerman
2020-06-09 5:53 ` Christoph Hellwig
0 siblings, 1 reply; 4+ messages in thread
From: Michael Ellerman @ 2020-06-09 5:28 UTC (permalink / raw)
To: Christophe Leroy, Paul Mackerras, Benjamin Herrenschmidt,
Michael Ellerman, naveen.n.rao
Cc: linuxppc-dev, linux-kernel
On Mon, 24 Feb 2020 18:02:10 +0000 (UTC), Christophe Leroy wrote:
> In order to avoid Oopses, use probe_address() to read the
> instruction at the address where the trap happened.
Applied to powerpc/next.
[1/1] powerpc/kprobes: Use probe_address() to read instructions
https://git.kernel.org/powerpc/c/9ed5df69b79a22b40b20bc2132ba2495708b19c4
cheers
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] powerpc/kprobes: Use probe_address() to read instructions
2020-06-09 5:28 ` Michael Ellerman
@ 2020-06-09 5:53 ` Christoph Hellwig
2020-06-10 10:12 ` Michael Ellerman
0 siblings, 1 reply; 4+ messages in thread
From: Christoph Hellwig @ 2020-06-09 5:53 UTC (permalink / raw)
To: Michael Ellerman
Cc: Christophe Leroy, linux-kernel, Paul Mackerras, naveen.n.rao,
linuxppc-dev
On Tue, Jun 09, 2020 at 03:28:38PM +1000, Michael Ellerman wrote:
> On Mon, 24 Feb 2020 18:02:10 +0000 (UTC), Christophe Leroy wrote:
> > In order to avoid Oopses, use probe_address() to read the
> > instruction at the address where the trap happened.
>
> Applied to powerpc/next.
>
> [1/1] powerpc/kprobes: Use probe_address() to read instructions
> https://git.kernel.org/powerpc/c/9ed5df69b79a22b40b20bc2132ba2495708b19c4
probe_addresss has been renamed to get_kernel_nofault in the -mm
queue that Andrew sent off to Linus last night.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] powerpc/kprobes: Use probe_address() to read instructions
2020-06-09 5:53 ` Christoph Hellwig
@ 2020-06-10 10:12 ` Michael Ellerman
0 siblings, 0 replies; 4+ messages in thread
From: Michael Ellerman @ 2020-06-10 10:12 UTC (permalink / raw)
To: Christoph Hellwig, Michael Ellerman
Cc: Christophe Leroy, linux-kernel, Paul Mackerras, naveen.n.rao,
linuxppc-dev
Christoph Hellwig <hch@infradead.org> writes:
> On Tue, Jun 09, 2020 at 03:28:38PM +1000, Michael Ellerman wrote:
>> On Mon, 24 Feb 2020 18:02:10 +0000 (UTC), Christophe Leroy wrote:
>> > In order to avoid Oopses, use probe_address() to read the
>> > instruction at the address where the trap happened.
>>
>> Applied to powerpc/next.
>>
>> [1/1] powerpc/kprobes: Use probe_address() to read instructions
>> https://git.kernel.org/powerpc/c/9ed5df69b79a22b40b20bc2132ba2495708b19c4
>
> probe_addresss has been renamed to get_kernel_nofault in the -mm
> queue that Andrew sent off to Linus last night.
That commit above is actually already in mainline, I was just _really_
behind on sending the patch notifications.
cheers
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-02-24 18:02 [PATCH] powerpc/kprobes: Use probe_address() to read instructions Christophe Leroy
2020-06-09 5:28 ` Michael Ellerman
2020-06-09 5:53 ` Christoph Hellwig
2020-06-10 10:12 ` Michael Ellerman
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