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authorGeert Uytterhoeven <geert@linux-m68k.org>2019-05-16 09:09:35 +0200
committerThomas Gleixner <tglx@linutronix.de>2019-06-26 16:56:21 +0200
commit1bf72720281770162c87990697eae1ba2f1d917a (patch)
treec2bca252b3baf7cde85cea480b19f77d79301671
parent4b972a01a7da614b4796475f933094751a295a2f (diff)
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cpu/speculation: Warn on unsupported mitigations= parameter
Currently, if the user specifies an unsupported mitigation strategy on the kernel command line, it will be ignored silently. The code will fall back to the default strategy, possibly leaving the system more vulnerable than expected. This may happen due to e.g. a simple typo, or, for a stable kernel release, because not all mitigation strategies have been backported. Inform the user by printing a message. Fixes: 98af8452945c5565 ("cpu/speculation: Add 'mitigations=' cmdline option") Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190516070935.22546-1-geert@linux-m68k.org
-rw-r--r--kernel/cpu.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 077fde6fb953..551db494f153 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2339,6 +2339,9 @@ static int __init mitigations_parse_cmdline(char *arg)
cpu_mitigations = CPU_MITIGATIONS_AUTO;
else if (!strcmp(arg, "auto,nosmt"))
cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT;
+ else
+ pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n",
+ arg);
return 0;
}