The commit is pushed to "branch-rh7-3.10.0-514.16.1.vz7.32.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-514.16.1.vz7.32.6
------>
commit 180af1fedac815f9fb983ee1acc3cdd96ccaf0d8
Author: Eugene Shatokhin <eugene.shatok...@rosalab.ru>
Date: Mon Jun 5 16:53:35 2017 +0400
ms/kprobes/x86: Return correct length in __copy_instruction()
ms commit: c80e5c0c23ce2282476fdc64c4b5e3d3a40723fd
On x86-64, __copy_instruction() always returns 0 (error) if the
instruction uses %rip-relative addressing. This is because
kernel_insn_init() is called the second time for 'insn' instance
in such cases and sets all its fields to 0.
Because of this, trying to place a kprobe on such instruction
will fail, register_kprobe() will return -EINVAL.
This patch fixes the problem.
Signed-off-by: Eugene Shatokhin <eugene.shatok...@rosalab.ru>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Link:
http://lkml.kernel.org/r/20150317100918.28349.94654.stgit@localhost.localdomain
Signed-off-by: Ingo Molnar <mi...@kernel.org>
https://jira.sw.ru/browse/PSBM-66876
---
arch/x86/kernel/kprobes/core.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 37330ee..39f2d05 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -327,21 +327,24 @@ int __kprobes __copy_instruction(u8 *dest, u8 *src)
{
struct insn insn;
kprobe_opcode_t buf[MAX_INSN_SIZE];
+ int length;
unsigned long recovered_insn =
recover_probed_instruction(buf, (unsigned long)src);
kernel_insn_init(&insn, (void *)recovered_insn, MAX_INSN_SIZE);
insn_get_length(&insn);
+ length = insn.length;
+
/* Another subsystem puts a breakpoint, failed to recover */
if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION)
return 0;
- memcpy(dest, insn.kaddr, insn.length);
+ memcpy(dest, insn.kaddr, length);
#ifdef CONFIG_X86_64
if (insn_rip_relative(&insn)) {
s64 newdisp;
u8 *disp;
- kernel_insn_init(&insn, dest, insn.length);
+ kernel_insn_init(&insn, dest, length);
insn_get_displacement(&insn);
/*
* The copied instruction uses the %rip-relative addressing
@@ -365,7 +368,7 @@ int __kprobes __copy_instruction(u8 *dest, u8 *src)
*(s32 *) disp = (s32) newdisp;
}
#endif
- return insn.length;
+ return length;
}
static int __kprobes arch_copy_kprobe(struct kprobe *p)
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