From: Thadeu Lima de Souza Cascardo cascardo@canonical.com
stable inclusion from stable-v5.10.144 commit 33015556a943d6cbb18c555925a54b8c0e46f521 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5WL0J CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=l...
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This reverts commit 00b136bb6254e0abf6aaafe62c4da5f6c4fea4cb.
This temporarily reverts the backport of upstream commit 1f001e9da6bbf482311e45e48f53c2bd2179e59c. It was not correct to copy the ftrace stub as it would contain a relative jump to the return thunk which would not apply to the context where it was being copied to, leading to ftrace support to be broken.
Signed-off-by: Thadeu Lima de Souza Cascardo cascardo@canonical.com Signed-off-by: Ovidiu Panait ovidiu.panait@windriver.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Lin Yujun linyujun809@huawei.com Reviewed-by: Zhang Jianhua chris.zjh@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/x86/kernel/ftrace.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index dca5cf82144c..fbcd144260ac 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -308,7 +308,7 @@ union ftrace_op_code_union { } __attribute__((packed)); };
-#define RET_SIZE (IS_ENABLED(CONFIG_RETPOLINE) ? 5 : 1 + IS_ENABLED(CONFIG_SLS)) +#define RET_SIZE 1 + IS_ENABLED(CONFIG_SLS)
static unsigned long create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) @@ -367,10 +367,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
/* The trampoline ends with ret(q) */ retq = (unsigned long)ftrace_stub; - if (cpu_feature_enabled(X86_FEATURE_RETHUNK)) - memcpy(ip, text_gen_insn(JMP32_INSN_OPCODE, ip, &__x86_return_thunk), JMP32_INSN_SIZE); - else - ret = copy_from_kernel_nofault(ip, (void *)retq, RET_SIZE); + ret = copy_from_kernel_nofault(ip, (void *)retq, RET_SIZE); if (WARN_ON(ret < 0)) goto fail;