This is a note to let you know that I've just added the patch titled x86/mce: Mark mce_end() noinstr to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-mce-mark-mce_end-noinstr.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 719c6a7e8f3ea39406c9eb8944f4d2bd36261c7e Author: Borislav Petkov <bp@xxxxxxx> Date: Mon Nov 1 16:43:33 2021 +0100 x86/mce: Mark mce_end() noinstr [ Upstream commit b4813539d37fa31fed62cdfab7bd2dd8929c5b2e ] It is called by the #MC handler which is noinstr. Fixes vmlinux.o: warning: objtool: do_machine_check()+0xbd6: call to memset() leaves .noinstr.text section Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lore.kernel.org/r/20211208111343.8130-9-bp@xxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index c5a1022463bcc..c37a0bcf2744b 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -1081,10 +1081,13 @@ static int mce_start(int *no_way_out) * Synchronize between CPUs after main scanning loop. * This invokes the bulk of the Monarch processing. */ -static int mce_end(int order) +static noinstr int mce_end(int order) { - int ret = -1; u64 timeout = (u64)mca_cfg.monarch_timeout * NSEC_PER_USEC; + int ret = -1; + + /* Allow instrumentation around external facilities. */ + instrumentation_begin(); if (!timeout) goto reset; @@ -1128,7 +1131,8 @@ static int mce_end(int order) /* * Don't reset anything. That's done by the Monarch. */ - return 0; + ret = 0; + goto out; } /* @@ -1144,6 +1148,10 @@ static int mce_end(int order) * Let others run again. */ atomic_set(&mce_executing, 0); + +out: + instrumentation_end(); + return ret; }