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SubjectRe: [PATCH] x86/spectre: fix an error message
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On Wed, 2018-02-14 at 10:14 +0300, Dan Carpenter wrote:
> If i == ARRAY_SIZE(mitigation_options) then we accidentally print
> garbage from one space beyond the end of the mitigation_options[] array.
>
> Fixes: 9005c6834c0f ("x86/spectre: Simplify spectre_v2 command line parsing")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
> index debcdda88560..acee4ebec04f 100644
> --- a/arch/x86/kernel/cpu/bugs.c
> +++ b/arch/x86/kernel/cpu/bugs.c
> @@ -174,7 +174,7 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
> }
>
> if (i >= ARRAY_SIZE(mitigation_options)) {
> - pr_err("unknown option (%s). Switching to AUTO select\n", mitigation_options[i].option);
> + pr_err("unknown option (%s). Switching to AUTO select\n", arg);
> return SPECTRE_V2_CMD_AUTO;
> }
> }

Should probably unindent this block too by
removing the else after the return

---
arch/x86/kernel/cpu/bugs.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 4acf16a76d1e..0af8245afb6c 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -161,22 +161,21 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)

if (cmdline_find_option_bool(boot_command_line, "nospectre_v2"))
return SPECTRE_V2_CMD_NONE;
- else {
- ret = cmdline_find_option(boot_command_line, "spectre_v2", arg, sizeof(arg));
- if (ret < 0)
- return SPECTRE_V2_CMD_AUTO;
-
- for (i = 0; i < ARRAY_SIZE(mitigation_options); i++) {
- if (!match_option(arg, ret, mitigation_options[i].option))
- continue;
- cmd = mitigation_options[i].cmd;
- break;
- }

- if (i >= ARRAY_SIZE(mitigation_options)) {
- pr_err("unknown option (%s). Switching to AUTO select\n", mitigation_options[i].option);
- return SPECTRE_V2_CMD_AUTO;
- }
+ ret = cmdline_find_option(boot_command_line, "spectre_v2", arg, sizeof(arg));
+ if (ret < 0)
+ return SPECTRE_V2_CMD_AUTO;
+
+ for (i = 0; i < ARRAY_SIZE(mitigation_options); i++) {
+ if (!match_option(arg, ret, mitigation_options[i].option))
+ continue;
+ cmd = mitigation_options[i].cmd;
+ break;
+ }
+
+ if (i >= ARRAY_SIZE(mitigation_options)) {
+ pr_err("unknown option (%s). Switching to AUTO select\n", arg);
+ return SPECTRE_V2_CMD_AUTO;
}

if ((cmd == SPECTRE_V2_CMD_RETPOLINE ||

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